1. The authors propose searching lunar surface photos from the Lunar Reconnaissance Orbiter for signs of extraterrestrial artifacts or technology.
2. Possible artifacts could include probes left to monitor Earth, trash from alien expeditions, or signs of mining or construction activities.
3. The moon is a good target for this search because it is close, signs would be well-preserved over immense timescales, and high-resolution photos are already being taken for other scientific purposes. Systematically analyzing these photos could help widen the search for extraterrestrial intelligence.
This document presents the target selection process for the first year of the Breakthrough Listen search for intelligent life using the Green Bank Telescope, Parkes Telescope, and Automated Planet Finder. The targets include: 1) The 60 nearest stars within 5.1 parsecs to search for faint signals; 2) 1649 stars spanning stellar types from the Hipparcos catalog; 3) 123 nearby galaxies representing different morphological types to search billions of stars simultaneously; and 4) several classes of exotic objects like white dwarfs and neutron stars. The telescopes will observe 1,000,000 stars and galaxies at radio and optical wavelengths between 350 MHz to 100 GHz and 374-950nm, respectively, to search for technological signals.
Frank Drake organized the first scientific meeting to discuss the possibility of discovering life on other worlds in 1961. He created what became known as the Drake Equation to summarize the key factors needed to estimate the number of detectable civilizations in our galaxy. The equation multiplied terms for the rate of star formation, the fraction of stars with planets, the number of planets that could support life, the fraction where life emerges and develops intelligence, the fraction that develop technologies for communication, and the length of time such civilizations remain detectable. At the meeting, estimates for the factors produced a value close to 1 for the number of civilizations, depending largely on how long they remain detectable. The Drake Equation became widely known and helped focus discussion on the challenges of
The study examines a post-starburst galaxy outflow using ultraviolet spectroscopy of multiple ions including hydrogen. It finds the outflow extends at least 160,000 light-years from the galaxy and contains a hidden mass of at least 6x10^9 times the mass of our Sun. This challenges previous assumptions about the extent and mass of galaxy outflows, suggesting they may play a larger role in regulating galaxy evolution than thought.
This study examines a reservoir of ionized gas in the galactic halo that can sustain star formation in the Milky Way. The authors detect a substantial amount of warm-hot gas in the halo of a star-forming galaxy at z=0.2 through detection of Ne VIII absorption lines. This warm-hot gas reservoir contains as much mass as the galaxy's stars and can replenish its supply of cool gas to sustain star formation over billions of years.
1) The document discusses the Baryon Oscillation Spectroscopic Survey (BOSS) which uses aluminum plates with holes arranged to match galaxy positions to measure distances and speeds of galaxies.
2) BOSS aims to measure dark energy by tracking how the spacing of large scale cosmic structures has expanded over billions of years. Its initial findings from 470,000 galaxies will be presented soon.
3) Future surveys like BigBOSS plan to map millions more galaxies and quasars to further study dark energy and determine if it has truly remained constant over time or if gravity behaves differently on large scales.
Ecsite 2012 - Science Centers and Planetaria as Citizen Science Platformsunawe
The latest developments in technology are changing the way we handle and process scientific data. A vast number of people make use of online mediums like Wikipedia, facebook, twitter etc, which allow fast and easy access to all kinds of scientific information. As a lot of scientific databases are nowadays available online, the scientists are no longer the main information gatekeepers.
Making use of this data and media for education and dissemination of science is a key challenge for science centres in the near future.
The document discusses the discovery of the dwarf planet Eris. In 2003, astronomers Mike Brown, Chad Trujillo, and David Rabinowitz discovered an object they initially called 2003 UB313 that was later named Eris. Eris is over 25% more massive than Pluto and orbits further from the sun. Its discovery reignited the debate around what defines a planet. In 2006, the International Astronomical Union officially designated Eris as a dwarf planet along with Pluto, defining a planet as clearing its orbit. Eris' moon was named Dysnomia, the goddess of lawlessness in Greek mythology.
SN 2011fe was a type Ia supernova discovered in the Pinwheel galaxy just 11 hours after it exploded, making it the youngest type Ia ever observed. Theoretical astrophysicist Peter Nugent discovered it and quickly organized follow up observations by telescopes. Over the following weeks, Nugent, Joshua Bloom, and Weidong Li intensely studied SN 2011fe to learn more about the origins and evolution of type Ia supernovae. Their work provided new insights, but tragically not all three researchers would still be alive to see the results and papers that came from this unique observation of a young supernova.
This document presents the target selection process for the first year of the Breakthrough Listen search for intelligent life using the Green Bank Telescope, Parkes Telescope, and Automated Planet Finder. The targets include: 1) The 60 nearest stars within 5.1 parsecs to search for faint signals; 2) 1649 stars spanning stellar types from the Hipparcos catalog; 3) 123 nearby galaxies representing different morphological types to search billions of stars simultaneously; and 4) several classes of exotic objects like white dwarfs and neutron stars. The telescopes will observe 1,000,000 stars and galaxies at radio and optical wavelengths between 350 MHz to 100 GHz and 374-950nm, respectively, to search for technological signals.
Frank Drake organized the first scientific meeting to discuss the possibility of discovering life on other worlds in 1961. He created what became known as the Drake Equation to summarize the key factors needed to estimate the number of detectable civilizations in our galaxy. The equation multiplied terms for the rate of star formation, the fraction of stars with planets, the number of planets that could support life, the fraction where life emerges and develops intelligence, the fraction that develop technologies for communication, and the length of time such civilizations remain detectable. At the meeting, estimates for the factors produced a value close to 1 for the number of civilizations, depending largely on how long they remain detectable. The Drake Equation became widely known and helped focus discussion on the challenges of
The study examines a post-starburst galaxy outflow using ultraviolet spectroscopy of multiple ions including hydrogen. It finds the outflow extends at least 160,000 light-years from the galaxy and contains a hidden mass of at least 6x10^9 times the mass of our Sun. This challenges previous assumptions about the extent and mass of galaxy outflows, suggesting they may play a larger role in regulating galaxy evolution than thought.
This study examines a reservoir of ionized gas in the galactic halo that can sustain star formation in the Milky Way. The authors detect a substantial amount of warm-hot gas in the halo of a star-forming galaxy at z=0.2 through detection of Ne VIII absorption lines. This warm-hot gas reservoir contains as much mass as the galaxy's stars and can replenish its supply of cool gas to sustain star formation over billions of years.
1) The document discusses the Baryon Oscillation Spectroscopic Survey (BOSS) which uses aluminum plates with holes arranged to match galaxy positions to measure distances and speeds of galaxies.
2) BOSS aims to measure dark energy by tracking how the spacing of large scale cosmic structures has expanded over billions of years. Its initial findings from 470,000 galaxies will be presented soon.
3) Future surveys like BigBOSS plan to map millions more galaxies and quasars to further study dark energy and determine if it has truly remained constant over time or if gravity behaves differently on large scales.
Ecsite 2012 - Science Centers and Planetaria as Citizen Science Platformsunawe
The latest developments in technology are changing the way we handle and process scientific data. A vast number of people make use of online mediums like Wikipedia, facebook, twitter etc, which allow fast and easy access to all kinds of scientific information. As a lot of scientific databases are nowadays available online, the scientists are no longer the main information gatekeepers.
Making use of this data and media for education and dissemination of science is a key challenge for science centres in the near future.
The document discusses the discovery of the dwarf planet Eris. In 2003, astronomers Mike Brown, Chad Trujillo, and David Rabinowitz discovered an object they initially called 2003 UB313 that was later named Eris. Eris is over 25% more massive than Pluto and orbits further from the sun. Its discovery reignited the debate around what defines a planet. In 2006, the International Astronomical Union officially designated Eris as a dwarf planet along with Pluto, defining a planet as clearing its orbit. Eris' moon was named Dysnomia, the goddess of lawlessness in Greek mythology.
SN 2011fe was a type Ia supernova discovered in the Pinwheel galaxy just 11 hours after it exploded, making it the youngest type Ia ever observed. Theoretical astrophysicist Peter Nugent discovered it and quickly organized follow up observations by telescopes. Over the following weeks, Nugent, Joshua Bloom, and Weidong Li intensely studied SN 2011fe to learn more about the origins and evolution of type Ia supernovae. Their work provided new insights, but tragically not all three researchers would still be alive to see the results and papers that came from this unique observation of a young supernova.
Zprávy mimozemšťanům - přednáška a synopse k článku do Živlu č. 39Pavel Vachtl
The document discusses potential methods of communicating with extraterrestrial civilizations, including:
1) Using mathematics as a universal language through symbols like prime numbers and geometric shapes.
2) Proposed projects that have sent messages into space aimed at nearby stars, including the Arecibo message broadcast in 1974 targeting a globular cluster 25,000 light years away.
3) Physical messages attached to space probes like the Pioneer plaque sent in 1972 depicting scientific concepts like the hydrogen atom and human figures to provide context about humanity and our location in the solar system.
The document discusses astrobiology and the Search for Extraterrestrial Intelligence (SETI) Institute. It describes the three centers at SETI that focus on researching life in the universe, studying conditions for life on and off Earth, and education/outreach. SETI uses radio telescopes like the Allen Telescope Array to search for signals from intelligent civilizations, but detecting credible signals is challenging. The Drake Equation aims to estimate the number of detectable civilizations but has many unknown variables. While the search for life continues, no conclusive evidence of extraterrestrial intelligence has been found so far.
LOFAR is a radio telescope array operated by ASTRON in the Netherlands that uses thousands of antennas to observe low frequency radio waves. It is being used for several key science projects including studying the Epoch of Reionization in the early universe, conducting deep surveys of galaxies to learn about their formation, and observing transient sources like exploding stars. One potential future use is detecting auroral activity on exoplanets through their unique radio signatures, which could reveal new planets and help characterize exoplanet magnetospheres and atmospheres.
Delivery of dark_material_to_vesta_via_carbonaceous_chondritic_impactsSérgio Sacani
This document analyzes dark material (DM) observed on the surface of asteroid Vesta by NASA's Dawn spacecraft. Spectral analysis finds the DM has properties similar to carbonaceous chondrite meteorites mixed with Vestan surface materials. Laboratory experiments matching the albedo and absorption bands of DM used mixtures of carbonaceous chondrites and eucrite basalt. Impact modeling suggests the DM was delivered via impacts of carbonaceous chondrite asteroids during the formation of the large Veneneia impact basin on Vesta. This supports the idea that carbonaceous chondrites were an important early source of carbon and volatiles in the solar system.
This was a talk I gave at CU Boulder SEDs in Nov 2011 to showcase the variety and opportunities for student-run science and engineering experiments on suborbital platforms. The area of suborbital space is rapidly expanding and is set to change how we expand our use of technology for future science and exploration space missions.
The document summarizes the first results from an ambitious HARPS program to detect Earth-like planets around nearby solar-type stars using high-precision radial velocity measurements. It reports the discovery of five new low-mass planets around the stars HD 20794, HD 85512, and HD 192310, including a system of three super-Earths and a planet with a mass of 3.6 Earth masses located at the inner edge of the habitable zone. This confirms previous indications that low-mass planets seem to be very frequent around solar-type stars, with an occurrence rate that may be higher than 30%.
This document discusses two alternative strategies for communicating with extraterrestrial intelligence - sending electromagnetic signals or physical objects through space. It summarizes a recent paper arguing that sending physical packages of information across interstellar distances could be more efficient than beams of electromagnetic radiation for long messages. While radio telescopes have searched for electromagnetic signals, this article suggests SETI should also consider the possibility of finding physical artifacts containing information left by an advanced extraterrestrial civilization to enable one-way communication.
The document discusses two scales used to quantify the impact and importance of announcements regarding the discovery of extraterrestrial life or intelligence: the Rio Scale and the London Scale. It provides details on the parameters and scoring systems for each scale. The author examines how concepts like "technosignatures" and a "shadow biosphere" might affect the scales. The convergence of astrobiology and SETI research methods could require modifications to the scales. Experts should consider the scales' structures when investigating societal effects of discoveries.
The cosmic gorilla effect or the problem of undetected non terrestrial intell...Sérgio Sacani
This document discusses how human psychology and neurophysiology may be unintentionally biasing the search for non-terrestrial intelligence (NTI). It points out that focusing only on radio signals and known physics limits our perspective, and that more advanced civilizations could exploit dark matter or exist in other dimensions. It also suggests that focusing attention narrowly could cause us to miss obvious signs of NTI, similar to the "invisible gorilla" experiment on inattentional blindness. Broadening our concepts of what NTI may look and expanding our search across the electromagnetic spectrum and beyond known physics may improve our chances of detection.
Life, the Universe, andSETI in a NutshellSérgio Sacani
Todate,no
SETI
observing
program
hassucceededindetectinganyunambiguousevidenceofan
extraterrestrial
technology.Regrettably,
this
paper
willtherefore
not
dazzleyou
with
the
analysisof
the
contentsofanyinterstellarmessages.However,asis
appropriate
foraplenarypresentation,
this
paper
doesprovidean
update
on
the
state
of
SETI
programsworldwide.Itdiscusses
the
various flavors ofobservational
SETI
projectscurrentlyon
the
air,plansforfutureinstrumentation,recent
attempts
toproactively
plan
forsuccess,
andthe
prospectsforfuture
public/private
partnershipstofundtheseefforts.
Thepaper
concludes
with
some
tentative
responsesto
the What
ifeverybodyislistening,
and
nobodyis
transmitting?
query.
- The document discusses the search for extraterrestrial intelligence (SETI) through radio astronomy and the possibility of communicating with advanced civilizations on other planets.
- While estimates suggest there could be over a million advanced civilizations in the Milky Way galaxy, only a small fraction of stars have been examined so far in SETI efforts.
- Receiving a radio signal from an extraterrestrial civilization would provide insights into key questions about the origin and evolution of life and intelligence in the universe.
Searching for Intelligent Life on Other Planets is a Goal Worth PursuingNick White
Abstract
For centuries, humans have tilted back their heads and gazed upon the heavens in wonder. What’s out there and are we alone in this universe? This paper addresses the need for humans worldwide to continue our search for life on other planets, and argues that it is our natural instinct to discover new worlds, much like the early explorers of the 15th Century. The paper covers the leadership role of SETI, as well as the projected funds for such missions. Themes from fields like astrobiology, economics and motivation will be considered and analyzed from a neutral standpoint. This paper will entertain the notion that we may, in fact, be alone in this universe. Aside from the money, the interest and the people advocating for the extra-terrestrial search, this paper will also address the mathematical probability of life existing in our galaxy, using the famed Drake Equation, contemplating the “habitable zone,” and even looking at evidence of life already found. The paper concludes, explaining why the search for intelligent life on other planets and our universe is a worthwhile goal.
This document provides an overview of astronomy and the scientific method. It discusses:
1) Astronomy as the study of objects beyond Earth and how they interact, with the goal of organizing our understanding of the universe's history.
2) The scientific method as a process of making observations, developing hypotheses, and testing them through experiments or further observations. Hypotheses must be falsifiable to be scientific.
3) Scientific laws as consistent rules that describe natural phenomena, allowing our understanding to be applied universally throughout the universe. Laws are subject to revision with new evidence.
The document discusses detailed numerical modeling of multi-planet systems discovered by the Kepler spacecraft. The author aims to model the effect of tides on the formation and evolution of Kepler multi-planet systems with two close planets in tight orbits. They will extract data from NASA's exoplanet archive to build numerical models incorporating the latest understanding of tidal dissipation. Comparing models to observations may help explain trends in planetary properties and the long-term stability of these systems.
This document provides 10 examples of science fact or fiction questions related to space and sci-fi topics. It summarizes the evidence for whether each statement is factual or fictional. Key findings include that multiple planetary systems have been discovered, some microorganisms can survive in space without protection, and organisms have been found thriving in extremely hot water. However, there is no conclusive evidence of life beyond Earth and we do not currently have the technology for interstellar travel or teleporting people.
Working Paper (PDF) for 100YSS 2012 session on Vessel Archives Heath Rezabek
Existential Risk, Human Survival, and the Future of Life in the Universe:
Interstellar Civilization through Vessel Archives.
PDF of working paper for 100YSS Conference in Houston TX, Sep 13-16 2012. Session is a proposal for a type of very-long-term archive as habitat.
1. The document discusses the quest to detect extra-terrestrial life and the consequences this would have for science and society. It explores both the scientific and societal implications.
2. While only life on Earth is currently known, conditions suitable for harboring life are thought to exist on other worlds like Mars, Europa, and Enceladus. The discovery of life elsewhere would have fundamental impacts and challenge existing views of life's uniqueness.
3. There is much unknown about the origin and distribution of life in the universe. Key questions remain unanswered about whether life follows universal principles or if Earth's life arose from highly improbable chances. Detecting life elsewhere could help answer these questions.
Background
We can search for evidence of past, or even present, life forms within our own solar system, find
evidence of simple life on planets around other stars –- a planet where water could be present has
recently be found –- or even detect an intelligent signal from an alien civilization. The speaker was
a project scientist in the most sensitive search, Project Phoenix, ever undertaken. Sadly, no signals
were detected but a new 10 year search using two of the world’s largest radio telescopes is about
to begin and, during the next decade, a giant radio telescope, the Square Kilometer Array, will have
the sensitivity to detect alien signals from across the galaxy.
The document discusses science exploration and the NASA budget for fiscal year 2011. It supports building blocks for exploration through science missions like Hubble and Solar Dynamics Observatory to advance scientific discoveries. The budget also commits substantially to studying Earth and climate science. The document discusses exploring locations like low Earth orbit, the lunar surface, deep space, and Mars with robotic and human missions. It emphasizes that exploring places like near-Earth objects extends human experience and could help understand hazards. The James Webb Space Telescope is discussed as well as the potential for discovering life on other planets and enabling science through space servicing.
The document discusses the occupational characteristics of microbiologists. Microbiologists study microorganisms like bacteria, archaea, algae, fungi, protozoa and viruses. On a daily basis, microbiologists treat infections, identify and classify new organisms, and find new uses for existing organisms. They may also work in epidemiology and write research reports. Graduating with a biology degree from the University at Albany provides various career opportunities in fields like research, health, and education, including work as a microbiologist.
Zprávy mimozemšťanům - přednáška a synopse k článku do Živlu č. 39Pavel Vachtl
The document discusses potential methods of communicating with extraterrestrial civilizations, including:
1) Using mathematics as a universal language through symbols like prime numbers and geometric shapes.
2) Proposed projects that have sent messages into space aimed at nearby stars, including the Arecibo message broadcast in 1974 targeting a globular cluster 25,000 light years away.
3) Physical messages attached to space probes like the Pioneer plaque sent in 1972 depicting scientific concepts like the hydrogen atom and human figures to provide context about humanity and our location in the solar system.
The document discusses astrobiology and the Search for Extraterrestrial Intelligence (SETI) Institute. It describes the three centers at SETI that focus on researching life in the universe, studying conditions for life on and off Earth, and education/outreach. SETI uses radio telescopes like the Allen Telescope Array to search for signals from intelligent civilizations, but detecting credible signals is challenging. The Drake Equation aims to estimate the number of detectable civilizations but has many unknown variables. While the search for life continues, no conclusive evidence of extraterrestrial intelligence has been found so far.
LOFAR is a radio telescope array operated by ASTRON in the Netherlands that uses thousands of antennas to observe low frequency radio waves. It is being used for several key science projects including studying the Epoch of Reionization in the early universe, conducting deep surveys of galaxies to learn about their formation, and observing transient sources like exploding stars. One potential future use is detecting auroral activity on exoplanets through their unique radio signatures, which could reveal new planets and help characterize exoplanet magnetospheres and atmospheres.
Delivery of dark_material_to_vesta_via_carbonaceous_chondritic_impactsSérgio Sacani
This document analyzes dark material (DM) observed on the surface of asteroid Vesta by NASA's Dawn spacecraft. Spectral analysis finds the DM has properties similar to carbonaceous chondrite meteorites mixed with Vestan surface materials. Laboratory experiments matching the albedo and absorption bands of DM used mixtures of carbonaceous chondrites and eucrite basalt. Impact modeling suggests the DM was delivered via impacts of carbonaceous chondrite asteroids during the formation of the large Veneneia impact basin on Vesta. This supports the idea that carbonaceous chondrites were an important early source of carbon and volatiles in the solar system.
This was a talk I gave at CU Boulder SEDs in Nov 2011 to showcase the variety and opportunities for student-run science and engineering experiments on suborbital platforms. The area of suborbital space is rapidly expanding and is set to change how we expand our use of technology for future science and exploration space missions.
The document summarizes the first results from an ambitious HARPS program to detect Earth-like planets around nearby solar-type stars using high-precision radial velocity measurements. It reports the discovery of five new low-mass planets around the stars HD 20794, HD 85512, and HD 192310, including a system of three super-Earths and a planet with a mass of 3.6 Earth masses located at the inner edge of the habitable zone. This confirms previous indications that low-mass planets seem to be very frequent around solar-type stars, with an occurrence rate that may be higher than 30%.
This document discusses two alternative strategies for communicating with extraterrestrial intelligence - sending electromagnetic signals or physical objects through space. It summarizes a recent paper arguing that sending physical packages of information across interstellar distances could be more efficient than beams of electromagnetic radiation for long messages. While radio telescopes have searched for electromagnetic signals, this article suggests SETI should also consider the possibility of finding physical artifacts containing information left by an advanced extraterrestrial civilization to enable one-way communication.
The document discusses two scales used to quantify the impact and importance of announcements regarding the discovery of extraterrestrial life or intelligence: the Rio Scale and the London Scale. It provides details on the parameters and scoring systems for each scale. The author examines how concepts like "technosignatures" and a "shadow biosphere" might affect the scales. The convergence of astrobiology and SETI research methods could require modifications to the scales. Experts should consider the scales' structures when investigating societal effects of discoveries.
The cosmic gorilla effect or the problem of undetected non terrestrial intell...Sérgio Sacani
This document discusses how human psychology and neurophysiology may be unintentionally biasing the search for non-terrestrial intelligence (NTI). It points out that focusing only on radio signals and known physics limits our perspective, and that more advanced civilizations could exploit dark matter or exist in other dimensions. It also suggests that focusing attention narrowly could cause us to miss obvious signs of NTI, similar to the "invisible gorilla" experiment on inattentional blindness. Broadening our concepts of what NTI may look and expanding our search across the electromagnetic spectrum and beyond known physics may improve our chances of detection.
Life, the Universe, andSETI in a NutshellSérgio Sacani
Todate,no
SETI
observing
program
hassucceededindetectinganyunambiguousevidenceofan
extraterrestrial
technology.Regrettably,
this
paper
willtherefore
not
dazzleyou
with
the
analysisof
the
contentsofanyinterstellarmessages.However,asis
appropriate
foraplenarypresentation,
this
paper
doesprovidean
update
on
the
state
of
SETI
programsworldwide.Itdiscusses
the
various flavors ofobservational
SETI
projectscurrentlyon
the
air,plansforfutureinstrumentation,recent
attempts
toproactively
plan
forsuccess,
andthe
prospectsforfuture
public/private
partnershipstofundtheseefforts.
Thepaper
concludes
with
some
tentative
responsesto
the What
ifeverybodyislistening,
and
nobodyis
transmitting?
query.
- The document discusses the search for extraterrestrial intelligence (SETI) through radio astronomy and the possibility of communicating with advanced civilizations on other planets.
- While estimates suggest there could be over a million advanced civilizations in the Milky Way galaxy, only a small fraction of stars have been examined so far in SETI efforts.
- Receiving a radio signal from an extraterrestrial civilization would provide insights into key questions about the origin and evolution of life and intelligence in the universe.
Searching for Intelligent Life on Other Planets is a Goal Worth PursuingNick White
Abstract
For centuries, humans have tilted back their heads and gazed upon the heavens in wonder. What’s out there and are we alone in this universe? This paper addresses the need for humans worldwide to continue our search for life on other planets, and argues that it is our natural instinct to discover new worlds, much like the early explorers of the 15th Century. The paper covers the leadership role of SETI, as well as the projected funds for such missions. Themes from fields like astrobiology, economics and motivation will be considered and analyzed from a neutral standpoint. This paper will entertain the notion that we may, in fact, be alone in this universe. Aside from the money, the interest and the people advocating for the extra-terrestrial search, this paper will also address the mathematical probability of life existing in our galaxy, using the famed Drake Equation, contemplating the “habitable zone,” and even looking at evidence of life already found. The paper concludes, explaining why the search for intelligent life on other planets and our universe is a worthwhile goal.
This document provides an overview of astronomy and the scientific method. It discusses:
1) Astronomy as the study of objects beyond Earth and how they interact, with the goal of organizing our understanding of the universe's history.
2) The scientific method as a process of making observations, developing hypotheses, and testing them through experiments or further observations. Hypotheses must be falsifiable to be scientific.
3) Scientific laws as consistent rules that describe natural phenomena, allowing our understanding to be applied universally throughout the universe. Laws are subject to revision with new evidence.
The document discusses detailed numerical modeling of multi-planet systems discovered by the Kepler spacecraft. The author aims to model the effect of tides on the formation and evolution of Kepler multi-planet systems with two close planets in tight orbits. They will extract data from NASA's exoplanet archive to build numerical models incorporating the latest understanding of tidal dissipation. Comparing models to observations may help explain trends in planetary properties and the long-term stability of these systems.
This document provides 10 examples of science fact or fiction questions related to space and sci-fi topics. It summarizes the evidence for whether each statement is factual or fictional. Key findings include that multiple planetary systems have been discovered, some microorganisms can survive in space without protection, and organisms have been found thriving in extremely hot water. However, there is no conclusive evidence of life beyond Earth and we do not currently have the technology for interstellar travel or teleporting people.
Working Paper (PDF) for 100YSS 2012 session on Vessel Archives Heath Rezabek
Existential Risk, Human Survival, and the Future of Life in the Universe:
Interstellar Civilization through Vessel Archives.
PDF of working paper for 100YSS Conference in Houston TX, Sep 13-16 2012. Session is a proposal for a type of very-long-term archive as habitat.
1. The document discusses the quest to detect extra-terrestrial life and the consequences this would have for science and society. It explores both the scientific and societal implications.
2. While only life on Earth is currently known, conditions suitable for harboring life are thought to exist on other worlds like Mars, Europa, and Enceladus. The discovery of life elsewhere would have fundamental impacts and challenge existing views of life's uniqueness.
3. There is much unknown about the origin and distribution of life in the universe. Key questions remain unanswered about whether life follows universal principles or if Earth's life arose from highly improbable chances. Detecting life elsewhere could help answer these questions.
Background
We can search for evidence of past, or even present, life forms within our own solar system, find
evidence of simple life on planets around other stars –- a planet where water could be present has
recently be found –- or even detect an intelligent signal from an alien civilization. The speaker was
a project scientist in the most sensitive search, Project Phoenix, ever undertaken. Sadly, no signals
were detected but a new 10 year search using two of the world’s largest radio telescopes is about
to begin and, during the next decade, a giant radio telescope, the Square Kilometer Array, will have
the sensitivity to detect alien signals from across the galaxy.
The document discusses science exploration and the NASA budget for fiscal year 2011. It supports building blocks for exploration through science missions like Hubble and Solar Dynamics Observatory to advance scientific discoveries. The budget also commits substantially to studying Earth and climate science. The document discusses exploring locations like low Earth orbit, the lunar surface, deep space, and Mars with robotic and human missions. It emphasizes that exploring places like near-Earth objects extends human experience and could help understand hazards. The James Webb Space Telescope is discussed as well as the potential for discovering life on other planets and enabling science through space servicing.
The document discusses the occupational characteristics of microbiologists. Microbiologists study microorganisms like bacteria, archaea, algae, fungi, protozoa and viruses. On a daily basis, microbiologists treat infections, identify and classify new organisms, and find new uses for existing organisms. They may also work in epidemiology and write research reports. Graduating with a biology degree from the University at Albany provides various career opportunities in fields like research, health, and education, including work as a microbiologist.
This document proposes a new strategic paradigm called "Toroids" for optimally detecting Near Earth Objects (NEOs) that pose the greatest hazard to Earth. The current strategy of ground-based optical telescopes is suboptimal and will take too long to detect over 99% of threatening objects. The new strategy focuses on detecting NEOs with the lowest Minimum Orbit Intersection Distances (MOIDs) with Earth, as a low MOID is necessary for high hazard potential. It would involve intensely surveying a thin torus region surrounding Earth's orbit to most efficiently find the vast majority of threatening NEOs.
The Transcension Hypothesis: Sufficiently Advanced Civilizations Invariably L...Sérgio Sacani
The emerging science of evolutionary developmental (“evo devo”) biology can aid us in thinking about
our universe as both an evolutionary system, where most processes are unpredictable and creative, and a
developmental system, where a special few processes are predictable and constrained to produce farfuture-
specific emergent order, just as we see in the common developmental processes in two stars of an
identical population type, or in two genetically identical twins in biology. The transcension hypothesis
proposes that a universal process of evolutionary development guides all sufficiently advanced
civilizations into what may be called "inner space," a computationally optimal domain of increasingly
dense, productive, miniaturized, and efficient scales of space, time, energy, and matter, and eventually, to
a black-hole-like destination. Transcension as a developmental destiny might also contribute to the
solution to the Fermi paradox, the question of why we have not seen evidence of or received beacons
from intelligent civilizations. A few potential evolutionary, developmental, and information theoretic
reasons, mechanisms, and models for constrained transcension of advanced intelligence are briefly
considered. In particular, we introduce arguments that black holes may be a developmental destiny and
standard attractor for all higher intelligence, as they appear to some to be ideal computing, learning,
forward time travel, energy harvesting, civilization merger, natural selection, and universe replication
devices. In the transcension hypothesis, simpler civilizations that succeed in resisting transcension by
staying in outer (normal) space would be developmental failures, which are statistically very rare late in
the life cycle of any biological developing system. If transcension is a developmental process, we may
expect brief broadcasts or subtle forms of galactic engineering to occur in small portions of a few
galaxies, the handiwork of young and immature civilizations, but constrained transcension should be by
far the norm for all mature civilizations.
A Search for Technosignatures Around 11,680 Stars with the Green Bank Telesco...Sérgio Sacani
We conducted a search for narrowband radio signals over four observing sessions in 2020–2023 with
the L-band receiver (1.15–1.73 GHz) of the 100 m diameter Green Bank Telescope. We pointed the
telescope in the directions of 62 TESS Objects of Interest, capturing radio emissions from a total of
∼11,860 stars and planetary systems in the ∼9 arcminute beam of the telescope. All detections were
either automatically rejected or visually inspected and confirmed to be of anthropogenic nature. In
this work, we also quantified the end-to-end efficiency of radio SETI pipelines with a signal injection
and recovery analysis. The UCLA SETI pipeline recovers 94.0% of the injected signals over the usable
frequency range of the receiver and 98.7% of the injections when regions of dense RFI are excluded. In
another pipeline that uses incoherent sums of 51 consecutive spectra, the recovery rate is ∼15 times
smaller at ∼6%. The pipeline efficiency affects SETI search volume calculations as well as calculations
of upper bounds on the number of transmitting civilizations. We developed an improved Drake Figure
of Merit for SETI search volume calculations that includes the pipeline efficiency and frequency drift
rate coverage. Based on our observations, we found that there is a high probability (94.0–98.7%) that
fewer than ∼0.014% of stars earlier than M8 within 100 pc host a transmitter that is detectable in
our search (EIRP > 1012 W). Finally, we showed that the UCLA SETI pipeline natively detects the
signals detected with AI techniques by Ma et al. (2023).
UAP phenomena can be understood through a six-layer model that examines the physical, anti-physical, psychological, physiological, psychic, and cultural aspects of reported experiences. While UAP often appear to behave in physically impossible ways, everything observed is consistent with an advanced technology that integrates both physical and psychic phenomena. This technology seems aimed at manipulating witnesses on physiological and psychological levels in order to primarily influence cultural views in society. A unified scientific framework is needed to study these complex observations.
Transit timing observations from kepler i. statistical analysis of the first...Sérgio Sacani
This document analyzes transit timing observations from the first four months of Kepler mission data. It finds that at least 12% (~65) of planet candidates show evidence of transit timing variations (TTVs), suggesting non-Keplerian motion likely due to gravitational interactions with other planets. While longer observation time is needed, TTVs could confirm multiple planet systems identified by Kepler and provide insights into planetary system dynamics and planet formation. The analysis measures individual transit times, assesses the significance of any variations compared to linear and quadratic ephemeris models, and identifies planet candidates warranting further TTV study.
The document discusses the Drake Equation and strategies for searching for and communicating with extraterrestrial intelligence (SETI). It introduces the Drake Equation, which estimates the number of civilizations in our galaxy with whom communication might be possible. It discusses factors like the formation of planets, the development of life and intelligence. It also covers challenges like the distances involved, likely communication methods using radio wavelengths, how to target searches and potential signaling frequencies. Several ongoing and past SETI projects are summarized, like Ohio State University's detection of the "Wow! signal" in 1977 and the SERENDIP project at UC Berkeley that analyzes data from the Arecibo radio telescope.
Artificial intelligence is helping astronomers make new discoveries and analyze vast amounts of data more efficiently. A new technique using AI was able to automatically identify and count thousands of previously undetected craters on the moon. AI has also discovered new exoplanets, studied stellar sound waves to reveal properties of stars, found fast radio bursts that had evaded detection, and recognized patterns in galaxy images. Challenges remain, but AI is proving to be a valuable tool for astronomy by identifying patterns humans might miss and handling large datasets faster than human analysis alone.
Five thousand robots on a telescope in Arizona are mapping the universe by collecting data from galaxies to study dark energy. Dark energy is accelerating the expansion of the universe, but its properties are unknown. The robots use fiber optics to collect light from millions of galaxies over time, allowing scientists to map the expansion of the universe and how dark energy has affected it. By observing the redshift and baryon acoustic oscillations of distant galaxies, DESI aims to provide the most detailed 3D map of the universe to date and answer questions about the nature and future of the accelerating expansion caused by dark energy.
The curiosity to find earth-like planet can be dated to long time ago. But because of the incapability of the available technologies, it was a dream to detect planets beyond our solar system. After the time stated, the space research have taken a new leap and opened a new era of information. The concept of Exoplanet born. It can also be referred to as Extra Solar Planet. Any planet which is not within our solar system is Exoplanet. But an absolute definition is quite complex and problematic. So some of the important characteristics of an Exoplanet is it has to be earth-like environment, it can be giant or terrestrial type
Similar to Searching for alien_artifacts_on_the_moon (20)
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Gliese 12 b: A Temperate Earth-sized Planet at 12 pc Ideal for Atmospheric Tr...Sérgio Sacani
Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the
atmospheres of terrestrial planets via follow-up spectroscopic observations. However, the number of such planets
receiving low insolation is still small, limiting our ability to understand the diversity of the atmospheric
composition and climates of temperate terrestrial planets. We report the discovery of an Earth-sized planet
transiting the nearby (12 pc) inactive M3.0 dwarf Gliese 12 (TOI-6251) with an orbital period (Porb) of 12.76 days.
The planet, Gliese 12 b, was initially identified as a candidate with an ambiguous Porb from TESS data. We
confirmed the transit signal and Porb using ground-based photometry with MuSCAT2 and MuSCAT3, and
validated the planetary nature of the signal using high-resolution images from Gemini/NIRI and Keck/NIRC2 as
well as radial velocity (RV) measurements from the InfraRed Doppler instrument on the Subaru 8.2 m telescope
and from CARMENES on the CAHA 3.5 m telescope. X-ray observations with XMM-Newton showed the host
star is inactive, with an X-ray-to-bolometric luminosity ratio of log 5.7 L L X bol » - . Joint analysis of the light
curves and RV measurements revealed that Gliese 12 b has a radius of 0.96 ± 0.05 R⊕,a3σ mass upper limit of
3.9 M⊕, and an equilibrium temperature of 315 ± 6 K assuming zero albedo. The transmission spectroscopy metric
(TSM) value of Gliese 12 b is close to the TSM values of the TRAPPIST-1 planets, adding Gliese 12 b to the small
list of potentially terrestrial, temperate planets amenable to atmospheric characterization with JWST.
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...Sérgio Sacani
We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a
bright (V = 12.6 mag, K = 7.8 mag) metal-poor M4V star only 12.162 ± 0.005 pc away from the Solar system with one of the
lowest stellar activity levels known for M-dwarfs. A planet candidate was detected by TESS based on only 3 transits in sectors
42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations
with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory,
as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of
12.76144 ± 0.00006 d and a radius of 1.0 ± 0.1 R⊕, resulting in an equilibrium temperature of ∼315 K. Gliese 12 b has excellent
future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar
compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool
stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy.
The importance of continents, oceans and plate tectonics for the evolution of...Sérgio Sacani
Within the uncertainties of involved astronomical and biological parameters, the Drake Equation
typically predicts that there should be many exoplanets in our galaxy hosting active, communicative
civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is
often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing
the importance of planetary tectonic style for biological evolution. We summarize growing evidence
that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern
plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated
emergence and evolution of complex species. We further suggest that both continents and oceans
are required for ACCs because early evolution of simple life must happen in water but late evolution
of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox
(1) by adding two additional terms to the Drake Equation: foc
(the fraction of habitable exoplanets
with significant continents and oceans) and fpt
(the fraction of habitable exoplanets with significant
continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by
demonstrating that the product of foc
and fpt
is very small (< 0.00003–0.002). We propose that the lack
of evidence for ACCs reflects the scarcity of long-lived plate tectonics and/or continents and oceans on
exoplanets with primitive life.
A Giant Impact Origin for the First Subduction on EarthSérgio Sacani
Hadean zircons provide a potential record of Earth's earliest subduction 4.3 billion years ago. Itremains enigmatic how subduction could be initiated so soon after the presumably Moon‐forming giant impact(MGI). Earlier studies found an increase in Earth's core‐mantle boundary (CMB) temperature due to theaccumulation of the impactor's core, and our recent work shows Earth's lower mantle remains largely solid, withsome of the impactor's mantle potentially surviving as the large low‐shear velocity provinces (LLSVPs). Here,we show that a hot post‐impact CMB drives the initiation of strong mantle plumes that can induce subductioninitiation ∼200 Myr after the MGI. 2D and 3D thermomechanical computations show that a high CMBtemperature is the primary factor triggering early subduction, with enrichment of heat‐producing elements inLLSVPs as another potential factor. The models link the earliest subduction to the MGI with implications forunderstanding the diverse tectonic regimes of rocky planets.
Climate extremes likely to drive land mammal extinction during next supercont...Sérgio Sacani
Mammals have dominated Earth for approximately 55 Myr thanks to their
adaptations and resilience to warming and cooling during the Cenozoic. All
life will eventually perish in a runaway greenhouse once absorbed solar
radiation exceeds the emission of thermal radiation in several billions of
years. However, conditions rendering the Earth naturally inhospitable to
mammals may develop sooner because of long-term processes linked to
plate tectonics (short-term perturbations are not considered here). In
~250 Myr, all continents will converge to form Earth’s next supercontinent,
Pangea Ultima. A natural consequence of the creation and decay of Pangea
Ultima will be extremes in pCO2 due to changes in volcanic rifting and
outgassing. Here we show that increased pCO2, solar energy (F⨀;
approximately +2.5% W m−2 greater than today) and continentality (larger
range in temperatures away from the ocean) lead to increasing warming
hostile to mammalian life. We assess their impact on mammalian
physiological limits (dry bulb, wet bulb and Humidex heat stress indicators)
as well as a planetary habitability index. Given mammals’ continued survival,
predicted background pCO2 levels of 410–816 ppm combined with increased
F⨀ will probably lead to a climate tipping point and their mass extinction.
The results also highlight how global landmass configuration, pCO2 and F⨀
play a critical role in planetary habitability.
Constraints on Neutrino Natal Kicks from Black-Hole Binary VFTS 243Sérgio Sacani
The recently reported observation of VFTS 243 is the first example of a massive black-hole binary
system with negligible binary interaction following black-hole formation. The black-hole mass (≈10M⊙)
and near-circular orbit (e ≈ 0.02) of VFTS 243 suggest that the progenitor star experienced complete
collapse, with energy-momentum being lost predominantly through neutrinos. VFTS 243 enables us to
constrain the natal kick and neutrino-emission asymmetry during black-hole formation. At 68% confidence
level, the natal kick velocity (mass decrement) is ≲10 km=s (≲1.0M⊙), with a full probability distribution
that peaks when ≈0.3M⊙ were ejected, presumably in neutrinos, and the black hole experienced a natal
kick of 4 km=s. The neutrino-emission asymmetry is ≲4%, with best fit values of ∼0–0.2%. Such a small
neutrino natal kick accompanying black-hole formation is in agreement with theoretical predictions.
Detectability of Solar Panels as a TechnosignatureSérgio Sacani
In this work, we assess the potential detectability of solar panels made of silicon on an Earth-like
exoplanet as a potential technosignature. Silicon-based photovoltaic cells have high reflectance in the
UV-VIS and in the near-IR, within the wavelength range of a space-based flagship mission concept
like the Habitable Worlds Observatory (HWO). Assuming that only solar energy is used to provide
the 2022 human energy needs with a land cover of ∼ 2.4%, and projecting the future energy demand
assuming various growth-rate scenarios, we assess the detectability with an 8 m HWO-like telescope.
Assuming the most favorable viewing orientation, and focusing on the strong absorption edge in the
ultraviolet-to-visible (0.34 − 0.52 µm), we find that several 100s of hours of observation time is needed
to reach a SNR of 5 for an Earth-like planet around a Sun-like star at 10pc, even with a solar panel
coverage of ∼ 23% land coverage of a future Earth. We discuss the necessity of concepts like Kardeshev
Type I/II civilizations and Dyson spheres, which would aim to harness vast amounts of energy. Even
with much larger populations than today, the total energy use of human civilization would be orders of
magnitude below the threshold for causing direct thermal heating or reaching the scale of a Kardashev
Type I civilization. Any extraterrrestrial civilization that likewise achieves sustainable population
levels may also find a limit on its need to expand, which suggests that a galaxy-spanning civilization
as imagined in the Fermi paradox may not exist.
Jet reorientation in central galaxies of clusters and groups: insights from V...Sérgio Sacani
Recent observations of galaxy clusters and groups with misalignments between their central AGN jets
and X-ray cavities, or with multiple misaligned cavities, have raised concerns about the jet – bubble
connection in cooling cores, and the processes responsible for jet realignment. To investigate the
frequency and causes of such misalignments, we construct a sample of 16 cool core galaxy clusters and
groups. Using VLBA radio data we measure the parsec-scale position angle of the jets, and compare
it with the position angle of the X-ray cavities detected in Chandra data. Using the overall sample
and selected subsets, we consistently find that there is a 30% – 38% chance to find a misalignment
larger than ∆Ψ = 45◦ when observing a cluster/group with a detected jet and at least one cavity. We
determine that projection may account for an apparently large ∆Ψ only in a fraction of objects (∼35%),
and given that gas dynamical disturbances (as sloshing) are found in both aligned and misaligned
systems, we exclude environmental perturbation as the main driver of cavity – jet misalignment.
Moreover, we find that large misalignments (up to ∼ 90◦
) are favored over smaller ones (45◦ ≤ ∆Ψ ≤
70◦
), and that the change in jet direction can occur on timescales between one and a few tens of Myr.
We conclude that misalignments are more likely related to actual reorientation of the jet axis, and we
discuss several engine-based mechanisms that may cause these dramatic changes.
The solar dynamo begins near the surfaceSérgio Sacani
The magnetic dynamo cycle of the Sun features a distinct pattern: a propagating
region of sunspot emergence appears around 30° latitude and vanishes near the
equator every 11 years (ref. 1). Moreover, longitudinal flows called torsional oscillations
closely shadow sunspot migration, undoubtedly sharing a common cause2. Contrary
to theories suggesting deep origins of these phenomena, helioseismology pinpoints
low-latitude torsional oscillations to the outer 5–10% of the Sun, the near-surface
shear layer3,4. Within this zone, inwardly increasing differential rotation coupled with
a poloidal magnetic field strongly implicates the magneto-rotational instability5,6,
prominent in accretion-disk theory and observed in laboratory experiments7.
Together, these two facts prompt the general question: whether the solar dynamo is
possibly a near-surface instability. Here we report strong affirmative evidence in stark
contrast to traditional models8 focusing on the deeper tachocline. Simple analytic
estimates show that the near-surface magneto-rotational instability better explains
the spatiotemporal scales of the torsional oscillations and inferred subsurface
magnetic field amplitudes9. State-of-the-art numerical simulations corroborate these
estimates and reproduce hemispherical magnetic current helicity laws10. The dynamo
resulting from a well-understood near-surface phenomenon improves prospects
for accurate predictions of full magnetic cycles and space weather, affecting the
electromagnetic infrastructure of Earth.
Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...Sérgio Sacani
In the Nice model of solar system formation, Uranus and Neptune undergo an orbital upheaval,
sweeping through a planetesimal disk. The region of the disk from which material is accreted by
the ice giants during this phase of their evolution has not previously been identified. We perform
direct N-body orbital simulations of the four giant planets to determine the amount and origin of solid
accretion during this orbital upheaval. We find that the ice giants undergo an extreme bombardment
event, with collision rates as much as ∼3 per hour assuming km-sized planetesimals, increasing the
total planet mass by up to ∼0.35%. In all cases, the initially outermost ice giant experiences the
largest total enhancement. We determine that for some plausible planetesimal properties, the resulting
atmospheric enrichment could potentially produce sufficient latent heat to alter the planetary cooling
timescale according to existing models. Our findings suggest that substantial accretion during this
phase of planetary evolution may have been sufficient to impact the atmospheric composition and
thermal evolution of the ice giants, motivating future work on the fate of deposited solid material.
Exomoons & Exorings with the Habitable Worlds Observatory I: On the Detection...Sérgio Sacani
The highest priority recommendation of the Astro2020 Decadal Survey for space-based astronomy
was the construction of an observatory capable of characterizing habitable worlds. In this paper series
we explore the detectability of and interference from exomoons and exorings serendipitously observed
with the proposed Habitable Worlds Observatory (HWO) as it seeks to characterize exoplanets, starting
in this manuscript with Earth-Moon analog mutual events. Unlike transits, which only occur in systems
viewed near edge-on, shadow (i.e., solar eclipse) and lunar eclipse mutual events occur in almost every
star-planet-moon system. The cadence of these events can vary widely from ∼yearly to multiple events
per day, as was the case in our younger Earth-Moon system. Leveraging previous space-based (EPOXI)
lightcurves of a Moon transit and performance predictions from the LUVOIR-B concept, we derive
the detectability of Moon analogs with HWO. We determine that Earth-Moon analogs are detectable
with observation of ∼2-20 mutual events for systems within 10 pc, and larger moons should remain
detectable out to 20 pc. We explore the extent to which exomoon mutual events can mimic planet
features and weather. We find that HWO wavelength coverage in the near-IR, specifically in the 1.4 µm
water band where large moons can outshine their host planet, will aid in differentiating exomoon signals
from exoplanet variability. Finally, we predict that exomoons formed through collision processes akin
to our Moon are more likely to be detected in younger systems, where shorter orbital periods and
favorable geometry enhance the probability and frequency of mutual events.
Emergent ribozyme behaviors in oxychlorine brines indicate a unique niche for...Sérgio Sacani
Mars is a particularly attractive candidate among known astronomical objects
to potentially host life. Results from space exploration missions have provided
insights into Martian geochemistry that indicate oxychlorine species, particularly perchlorate, are ubiquitous features of the Martian geochemical landscape. Perchlorate presents potential obstacles for known forms of life due to
its toxicity. However, it can also provide potential benefits, such as producing
brines by deliquescence, like those thought to exist on present-day Mars. Here
we show perchlorate brines support folding and catalysis of functional RNAs,
while inactivating representative protein enzymes. Additionally, we show
perchlorate and other oxychlorine species enable ribozyme functions,
including homeostasis-like regulatory behavior and ribozyme-catalyzed
chlorination of organic molecules. We suggest nucleic acids are uniquely wellsuited to hypersaline Martian environments. Furthermore, Martian near- or
subsurface oxychlorine brines, and brines found in potential lifeforms, could
provide a unique niche for biomolecular evolution.
Continuum emission from within the plunging region of black hole discsSérgio Sacani
The thermal continuum emission observed from accreting black holes across X-ray bands has the potential to be leveraged as a
powerful probe of the mass and spin of the central black hole. The vast majority of existing ‘continuum fitting’ models neglect
emission sourced at and within the innermost stable circular orbit (ISCO) of the black hole. Numerical simulations, however,
find non-zero emission sourced from these regions. In this work, we extend existing techniques by including the emission
sourced from within the plunging region, utilizing new analytical models that reproduce the properties of numerical accretion
simulations. We show that in general the neglected intra-ISCO emission produces a hot-and-small quasi-blackbody component,
but can also produce a weak power-law tail for more extreme parameter regions. A similar hot-and-small blackbody component
has been added in by hand in an ad hoc manner to previous analyses of X-ray binary spectra. We show that the X-ray spectrum
of MAXI J1820+070 in a soft-state outburst is extremely well described by a full Kerr black hole disc, while conventional
models that neglect intra-ISCO emission are unable to reproduce the data. We believe this represents the first robust detection of
intra-ISCO emission in the literature, and allows additional constraints to be placed on the MAXI J1820 + 070 black hole spin
which must be low a• < 0.5 to allow a detectable intra-ISCO region. Emission from within the ISCO is the dominant emission
component in the MAXI J1820 + 070 spectrum between 6 and 10 keV, highlighting the necessity of including this region. Our
continuum fitting model is made publicly available.
Programming Foundation Models with DSPy - Meetup SlidesZilliz
Prompting language models is hard, while programming language models is easy. In this talk, I will discuss the state-of-the-art framework DSPy for programming foundation models with its powerful optimizers and runtime constraint system.
Threats to mobile devices are more prevalent and increasing in scope and complexity. Users of mobile devices desire to take full advantage of the features
available on those devices, but many of the features provide convenience and capability but sacrifice security. This best practices guide outlines steps the users can take to better protect personal devices and information.
GraphRAG for Life Science to increase LLM accuracyTomaz Bratanic
GraphRAG for life science domain, where you retriever information from biomedical knowledge graphs using LLMs to increase the accuracy and performance of generated answers
Webinar: Designing a schema for a Data WarehouseFederico Razzoli
Are you new to data warehouses (DWH)? Do you need to check whether your data warehouse follows the best practices for a good design? In both cases, this webinar is for you.
A data warehouse is a central relational database that contains all measurements about a business or an organisation. This data comes from a variety of heterogeneous data sources, which includes databases of any type that back the applications used by the company, data files exported by some applications, or APIs provided by internal or external services.
But designing a data warehouse correctly is a hard task, which requires gathering information about the business processes that need to be analysed in the first place. These processes must be translated into so-called star schemas, which means, denormalised databases where each table represents a dimension or facts.
We will discuss these topics:
- How to gather information about a business;
- Understanding dictionaries and how to identify business entities;
- Dimensions and facts;
- Setting a table granularity;
- Types of facts;
- Types of dimensions;
- Snowflakes and how to avoid them;
- Expanding existing dimensions and facts.
OpenID AuthZEN Interop Read Out - AuthorizationDavid Brossard
During Identiverse 2024 and EIC 2024, members of the OpenID AuthZEN WG got together and demoed their authorization endpoints conforming to the AuthZEN API
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1. Acta Astronautica ] (]]]]) ]]]–]]]
Contents lists available at SciVerse ScienceDirect
Acta Astronautica
journal homepage: www.elsevier.com/locate/actaastro
Searching for alien artifacts on the moon
P.C.W. Davies a,n, R.V. Wagner b
a
Beyond Center for Fundamental Concepts in Science at Arizona State University, PO Box 871504 Tempe, AZ 85287, USA
b
School of Earth and Space Exploration Lunar Recon Oribiter Sci Ops Cn, Arizona State University, Tempe, AZ, 85287, USA
a r t i c l e i n f o abstract
Article history: The Search for Extraterrestrial Intelligence (SETI) has a low probability of success, but it
Received 5 March 2011 would have a high impact if successful. Therefore it makes sense to widen the search as
Received in revised form much as possible within the confines of the modest budget and limited resources
7 October 2011
currently available. To date, SETI has been dominated by the paradigm of seeking
Accepted 29 October 2011
deliberately beamed radio messages.
However, indirect evidence for extraterrestrial intelligence could come from any
Keywords: incontrovertible signatures of non-human technology. Existing searchable databases
SETI from astronomy, biology, earth and planetary sciences all offer low-cost opportunities
Lunar reconnaissance orbiter
to seek a footprint of extraterrestrial technology. In this paper we take as a case study
Extraterrestrial technology
one particular new and rapidly-expanding database: the photographic mapping of the
Nuclear waste
Lava tubes Moon’s surface by the Lunar Reconnaissance Orbiter (LRO) to 0.5 m resolution.
Regolith Although there is only a tiny probability that alien technology would have left traces
on the moon in the form of an artifact or surface modification of lunar features, this
location has the virtue of being close, and of preserving traces for an immense duration.
Systematic scrutiny of the LRO photographic images is being routinely conducted
anyway for planetary science purposes, and this program could readily be expanded
and outsourced at little extra cost to accommodate SETI goals, after the fashion of the
SETI@home and Galaxy Zoo projects.
Published by Elsevier Ltd.
1. Background human capacity to meaningfully extrapolate regarding
its specific characteristics. If we therefore have no fixed
In 2010 the Search for Extraterrestrial Intelligence idea what to look for, it makes sense to search all
(SETI) was 50 years old, and the anniversary provided available and emerging databases for ‘‘artificiality,’’
an appropriate opportunity to take stock. In particular, whether deliberate (as in a message) or inadvertent (as
there have been calls to widen the search by considering in environmental impact). We argue that the criteria for
not just purposefully-directed radio messages, but the searching a database should be primarily tied to cost
most general signatures of intelligence [1]. Alien intelli- rather than plausibility. If it costs little to scan data for
gence, if it exists, or has existed, might have endured for a signs of intelligent manipulation [3], little is lost in doing
very long duration, measured in millions, tens or hun- so, even though the probability of detecting alien tech-
dreds of millions or even (in principle) billions of years, nology at work may be exceedingly low. A good example,
and will almost certainly be dominated by post-biological already discussed in the literature [4,5], is genomic
intelligent systems [1,2]. Thus it may lie far beyond SETI—the ‘‘message-in-a-bottle’’ scenario in which an
extraterrestrial civilization long ago uploaded a message
into the DNA of some terrestrial organisms, either roboti-
n
Corresponding author. cally or using viral vectors. Genome sequencing is taking
E-mail address: deepthought@asu.edu (P.C.W. Davies). place on a grand scale anyway, the results freely available
0094-5765/$ - see front matter Published by Elsevier Ltd.
doi:10.1016/j.actaastro.2011.10.022
Please cite this article as: P.C.W. Davies, R.V. Wagner, Searching for alien artifacts on the moon, Acta Astronaut. (2011),
doi:10.1016/j.actaastro.2011.10.022
2. 2 P.C.W. Davies, R.V. Wagner / Acta Astronautica ] (]]]]) ]]]–]]]
on the internet, and it would cost almost nothing to behind by an alien expedition or colonization wave, to
search the genomic database using a simple algorithm record data, perhaps about the development of life on
to seek out signs of intelligent manipulation. Earth, over a long period of time, and may or may not
In this paper we discuss a new database resource: the still be active.
photographic mapping of the lunar surface to a resolution of 3) Trash. Objects left behind by an alien expedition or
0.5 m, currently being conducted by the Lunar Reconnais- colonization wave, without any regard to whether or
sance Orbiter (LRO). (For a review of the mission in general, not they survived intact. These could range from
see Chin et al. [6], and of the camera system in particular, landing stages of spacecraft to spent radiogenic or
see Robinson et al. [7]). A persistent science fiction theme is other power sources.
that of an alien artifact left on the moon’s surface long ago 4) Geo-engineering structures. Not artifacts per se, but
(for example, Clarke [8]). Such an artifact might originate in changes to the moon’s surface caused by mining,
several ways, for example, discarded material from an alien quarrying or construction activities.
expedition or mining operation, instrumentation deliber-
ately installed to monitor Earth, or a dormant probe await- A key issue is when such a probe might have been sent,
ing contact (a variant on the message-in-a-bottle theme). or a visitation may have taken place, because that will
Alien technology might also manifest itself in mining or affect the detectability of any traces. Studies of extra-solar
quarrying activity, or even construction work, traces of planets suggest that earthlike planets may be common in
which might persist even after millions of years. Whatever the galaxy [12]. The galaxy is about 13 billion years old,
may be the reason for alien artifacts or engineering pro- but the solar system formed only about 4.5 billion years
cesses on the moon, the question that we address here is ago. If we restrict attention to carbon-based life, then the
whether we could in principle detect such a thing using LRO probability for life to emerge will slowly rise as a function
data or similar foreseeable surveys. of the availability of carbon and related elements. An
The moon has several factors in its favor as a place to estimate of the age distribution of terrestrial planets has
search for alien artifacts. First, it is close. Instruments based been given by Lineweaver [13]. Of course, we have no idea
on Earth can observe the surface in reasonably high detail, what the absolute probability is for life to arise on a
and instruments on the moon can communicate with Earth terrestrial-type planet once it exists. It could be very rare
at high bandwidths. Second, it is largely unchanging. The only [14,15], but for the purposes of this paper we shall adopt
major source of erosion and deposition comes from meteorite the optimistic position of Davis and Lineweaver [16] that
impacts, which occur at a very slow rate (the seismometer on the probability for abiogenesis it is not exceptionally low,
Apollo 12 detected only one grapefruit-sized impactor a and that there are consequently many planets with life in
month within a 350 km radius). The process of ‘gardening,’ our galaxy (and others). In spite of the steady increase
whereby continual disruption of the lunar surface by impacts over time of the relative probability for life to emerge,
leads to eventual burial, has been studied in the context of there is no reason to rule out the possibility that planets
locating terrestrial meteorites on the moon [9]. Calculations with life existed long before Earth formed, and that
indicate that it could take hundreds of millions of years for an planets with intelligent life and technological commu-
object a few tens of meters across to vanish by this process nities existed, and have existed, over astronomical time
beneath the dust and regolith [10,11]. However, gardening scales [17,1]. Thus there is no reason to suppose that an
also serves to re-expose buried objects over a long period of alien probe would have been sent to the solar system, or
time. Third, the moon is tectonically inactive, so any activity an alien visitation taken place, in the relatively recent past
caused by an artifact (heat, strong magnetic field, radio- (e.g. within the epoch of human habitation on Earth), as
opposed to the very far past. If the solar system were
activity, etc.) will show up clearly, rather than being hidden
visited, say, two billion years ago, it may be exceedingly
by other processes such as might occur on Earth. Thus any
difficult to identify any traces of alien technology even on
messages or traces of technological activity left on the moon
a fairly large scale. If the time scale was, say, one hundred
will likely still be around today, and should be possible to
million years, there is more likelihood of us finding traces,
locate without the vast expense that would go into searching
but our best hope is if we are dealing with a time scale of
more distant bodies, such as Mars. The question, then, is
a few million years or less.
what forms these artifacts might take, and why they might
have been left.
There are many conceivable reasons that aliens would 2. Messages
leave artifacts on the moon, including some that humans
may not even be able to guess at. If for the sake of argument This is the most attractive possible artifact type to find,
we assume an alien species with roughly human-like reason- as it shows that not only does alien intelligence exist, but
ing and motivation, there are four main classes of artifacts or that it cares (or cared) about communicating with other
technological modifications that we should consider intelligent beings, and may even be willing to impart
knowledge and wisdom to us. A message would likely be
1) Messages. These are artifacts specifically designed to be placed where it could be easily located, and might also
found and interpreted by an intelligent species that have some sort of beacon attached, so that orbital instru-
developed on Earth. ments would be able to find it even if the message capsule
2) Scientific instruments. These are observational devices was buried. However, the details of these features can
sent across interstellar space as robotic probes, or left vary widely depending on when the putative aliens
Please cite this article as: P.C.W. Davies, R.V. Wagner, Searching for alien artifacts on the moon, Acta Astronaut. (2011),
doi:10.1016/j.actaastro.2011.10.022
3. P.C.W. Davies, R.V. Wagner / Acta Astronautica ] (]]]]) ]]]–]]] 3
visited, and how long they expected the message to need might be just a few tens of meters across. Furthermore, an
to last. instrument would likely be coated in lunar dust after a
If aliens (or their probes or robotic surrogates) visited few hundred years, making it had to distinguish from a
in the last few thousand years, they would know that mundane geological feature. The best way to identify an
there was a developing technological society on Earth, active instrument would probably be to look for signs of
and they might leave a simple capsule in or near an its power source. Solar panels, if kept clean enough to
existing landmark, such as a large fresh crater like Tycho, keep the instrument powered, would probably appear as
perhaps with a radio beacon or a splash of paint to further large black geometric shapes. Radiogenic sources would
mark its location. In this case, the message could probably likely produce detectable gamma radiation, as there is
be spotted by orbital photography such as LRO. Messages little incentive for the aliens to go to the effort of shielding
designed to last only a few million years would probably the reactor. More exotic power sources might also pro-
be similar, although any beacon would need to be detect- duce detectable radiation, although we cannot currently
able through a few centimeters of regolith. However, predict what these might be, so there is no good way to
messages designed for such a timescale might be unlikely actively search for them.
unless the aliens could have predicted the eventual rise of Of the above, solar is the easiest to find with current
technological civilization based merely on the discovery data, such as from the LRO, and there is an obvious place
that Earth hosted one or more species of big-brained tool- to look for solar arrays. At the north and south poles, there
making animals. are regions that are in near-perpetual sunlight, usually
In the case of a message designed to last hundreds of very close to permanently-shadowed craters that could be
millions of years all bets are off. Over such a time scale, used to hold instruments that require very low tempera-
any given point is likely to be hit by a meteorite large tures, such as infrared telescopes. Thus, looking at high-
enough to destroy artifacts on the surface made out of any resolution images of these areas should reveal whether or
known material, so to survive for 4108 years the mes- not there are alien solar arrays installed. However, there is
sage would need to be securely buried at depth. There- very good high-resolution coverage of the lunar poles
fore, it would also need a beacon that is detectable thanks to the LRO NAC camera, and no obvious solar
through at least several meters of regolith. This could be arrays have been found so far.
long-wavelength radio, a strong magnetic field, or (in
principle) something more exotic such as a neutrino
generator. It could also, of course, involve some form of 4. Trash
more advanced technology as yet unknown to us. In any
case, there would probably be no visual evidence left on Any alien expedition that set down on the moon is
the moon’s surface to attract our attention that anything likely to have left some trash behind, as it is expensive to
of interest was in the area. However, there might still be a haul material out of any gravity well, even one as shallow
way to narrow the search. The north and south poles are as the moon’s. Aliens might not have been as wasteful as
obvious choices for placing messages, but thanks to the the Apollo missions, that left most of the equipment
moon’s tidally-locked orbit, there are other points that behind, along with half of the landing spacecraft, but they
can be uniquely pin-pointed over a long period of time, might still have left something. Finding small artifacts
such as the sub-Terran point (the point directly below the such as dropped tools is probably hopeless, but larger
Earth) and its antipode, and the centers of the leading and structures such as habitat domes or solar arrays might
trailing hemispheres in the moon’s orbit. One of these still be visible millions of years later.
might be deliberately chosen as the site of a message in One particular form of trash – spent radioactive fuel –
the knowledge that these points would have significance is an attractive target. Nuclear waste may contain radio-
to a scientifically literate terrestrial community. But with- nuclides with very long half lives, leaving traces that are
out any surface features to indicate the presence of a detectable for millions of years or even longer. (The Oklo
subsurface artifact, detection would have to depend on natural nuclear reactor discovered in Gabon, West Africa,
ground-penetrating radar or deliberate excavations by went critical about 2 billion years ago, and has been
future manned expeditions. intensively studied; see, for example, Petrov et al. [18])
Any deposits of plutonium, a good nuclear fuel, would
3. Scientific instruments stand out as a product of alien technology because the
half life of this element is much less than the age of the
These would be nearly as good as an actual message if solar system, so any primordial plutonium on the moon
we found them, as they would not only prove the would have decayed long ago. If a nuclear waste dump
existence of alien intelligence, they would tell us some- were found, it should be possible to date both the age of
thing about what the beings were interested in, and the fuel and the time that it was discarded. Nuclear
possibly allow us to communicate with them if they are material left on the surface of the moon would eventually
somehow monitoring the instruments. However, finding become buried, but for a long time it would still produce a
instruments would be much harder than finding a mes- distinctive signature as a radiation source (assuming it
sage, as the aliens would have no incentive to make an was unshielded) that could readily be detected from orbit
instrument easy to spot. Even a large radio telescope on on a future mission suitably equipped to search for
the far side of the moon (to shield it from potential radio gamma rays. However, it is unlikely that the LRO could
traffic from any future terrestrial technological society) assist in searching for nuclear waste, even if it is not
Please cite this article as: P.C.W. Davies, R.V. Wagner, Searching for alien artifacts on the moon, Acta Astronaut. (2011),
doi:10.1016/j.actaastro.2011.10.022
4. 4 P.C.W. Davies, R.V. Wagner / Acta Astronautica ] (]]]]) ]]]–]]]
buried, given that it would probably be small and searching for. For alien artifacts, we don’t have the luxury
inconspicuous. of knowing what latitude and longitude to target, so we
A good place to look for alien trash is inside one of the need to study the entire surface. Focusing on some
lava tubes located in the lunar maria. So far, three large regions of special geological interest would help, but
skylights have been discovered by the LRO, each about there would still be hundreds of images to look through.
100 m across, which might lead down into a subsurface The huge amount of data from the NAC is both its best
network, and several lunar pits point to a subsurface feature and the greatest obstacle to using it as a resource
labyrinth [19]. Lava tubes have been proposed as an ideal for seeking alien artifacts. Each NAC frame is 500 mega-
location to establish a human base, as they would provide pixels, and takes between 30 min and an hour to analyze
protection from radiation and meteorites; perhaps aliens in sufficient detail to be able to locate artifacts such as the
would come to the same conclusion. Furthermore, the Surveyor landers. So far more than 340,000 NAC images
same factors that make lava tubes attractive as a habitat have been released to the public, and that number will
imply that any artifacts left behind would endure almost likely approach 1,000,000 by the time it has achieved 100
indefinitely, undamaged and unburied. The downside is percent coverage. From these numbers, it is obvious that a
that there is no way to really investigate this possibility
manual search by a small team is hopeless. It might be
from orbit, so any confirmation or refutation will require a
possible to scan the entire dataset by ‘‘crowdsourcing’’ the
new robotic or human mission to the surface.
work to a few tens of thousands of people over the
Internet, and in fact this approach is being taken by the
5. Geo-engineering structures
website MoonZoo.org, which is trying to classify as many
features on the moon as possible by having people look at
If aliens used lunar material as a resource, they may
have carried out mining or quarrying activities, or even a few NAC frames each, and record what they find. The
have built large structures that could still be detected downside to this approach is that with so many people
from photographic surveys. The main difficulty in identi- involved, there will be differences in opinion on what is
fying the scars of major geo-engineering work would be and isn’t important. Without a lot of organization and
to distinguish them from naturally occurring features. A dedication, many images will get skipped and many
round open-cast mine, for example, may after some potentially interesting features overlooked. Nevertheless,
millions of years come to resemble an impact crater or this project will doubtless result in some claims of alien
collapsed lava tube at first sight, and only a careful artifacts, and one or more of them might conceivably be
analysis of the topography might reveal signs of artifici- correct.
ality. Excavations with more distinctive topography (spir- An alternative method of searching a large number of
als, rectangles, etc.) would be more conspicuous. Because images is computer automation. One of us (RW) has
we have no idea of the motives, capabilities or agenda of a written software able to identify simple pits as part of
very advanced alien technological community, we cannot the in-house LRO data analysis program currently being
guess what form of surface modification might ensue conducted at Arizona State University. This system is able
from an alien presence, even a fleeting one, on the moon. to run through about 200 images per hour. It merely
It therefore pays to be as broad as possible when seeking filters the images, identifying the features most likely to
signs of past geo-engineering activity. be pits, and presents them for a human analyst to decide
whether the features are interesting or not. However, it
6. Seeking artifacts using current data does allow a human to search thousands of images each
day for a specific feature.
The best available visible-light imagery of the moon Although automated searching offers great promise, a
comes from the Narrow Angle Camera (NAC) on the Lunar major obstacle is that computer software can only search
Reconnaissance Orbiter, which has been orbiting the for specific features that have been programmed in
moon since mid-2009 [7]. It has imaged over 25 percent advance. Thus, for example, crater detection algorithms
of the lunar surface at resolutions down to 50 cm/pixel, in are now fairly sophisticated [20,21]. However, when it
a variety of lighting angles. This dataset is so good that comes to ‘‘artificiality’’ there is inevitably an element of
several artifacts have in fact already been found, in both judgment involved at the outset as to what would con-
the Instrument and Trash categories. However, all of them stitute evidence. Certain features, such as regular geome-
were created by humans. These artifacts include not only trical shapes or sharp angles, are relatively easy to deal
the Apollo landing sites, which are easily identified by the with, but more subtle traces, for example, partially buried
thin dark trails of dust kicked up by the astronauts, but smooth surfaces or quarry boundaries, offer a greater
also all of the NASA and Soviet unmanned probes, which, challenge. As any forensic scientist can attest, physical
with the exception of the two soviet rovers that left evidence for intervention by an intelligent agent may be
kilometers-long tracks, have nothing to mark their loca- very subtle and require multiple lines of evidence and a
tion but their slightly odd-looking shadows, and some- lifetime of experience for it to become apparent. Because
times a small halo of disturbed dust from the landing we have no clear idea of what to look for, the task is
rockets. However, in all of these cases, the people who doubly difficult. Nevertheless, the NAC data is being
found the artifacts already knew approximately where to gathered anyway, and the cost of searching this
look, so they only needed to comb through a few NAC amazing resource, either by eye or by software, is rela-
images before they found the lander or rover they were tively modest.
Please cite this article as: P.C.W. Davies, R.V. Wagner, Searching for alien artifacts on the moon, Acta Astronaut. (2011),
doi:10.1016/j.actaastro.2011.10.022
5. P.C.W. Davies, R.V. Wagner / Acta Astronautica ] (]]]]) ]]]–]]] 5
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Paul Davies is Director of the Beyond Center
greatest scientific discoveries of all time. for Fundamental Concepts in Science at Ari-
zona State University. His research spans
cosmology, astrobiology and theoretical phy-
Acknowledgments sics. He has made important contributions to
quantum field theory in curved spacetime,
with applications to inflationary cosmology
We should like to thank Chris McKay and Mark and black holes. He was among the first to
Robinson for helpful discussions. champion the possibility that microbial life
could be transferred between Mars and Earth
in impact ejecta. He also runs a major cancer
References research program funded by the National
Cancer Institute. He is the author of 28
books, including most recently The Eerie Silence: Renewing Our Search
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Inter. Soc. 36 (1983) 501–506. and Space Exploration. He works as a
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Please cite this article as: P.C.W. Davies, R.V. Wagner, Searching for alien artifacts on the moon, Acta Astronaut. (2011),
doi:10.1016/j.actaastro.2011.10.022