The document provides information about the solar system and beyond. It summarizes that the solar system consists of the Sun and objects that orbit it, including 8 planets. It is located within the Milky Way galaxy, which contains many stars, dust and gas. The document then provides details about the properties of objects in the solar system like planets, moons, asteroids and comets.
1) Our solar system is located in the Milky Way Galaxy, which contains 200 billion stars.
2) Spiral galaxies have a central dense area and spiraling arms where stars often form. There are two types of spiral galaxies.
3) Our solar system consists of the sun and objects that orbit it like planets, moons, asteroids, comets, and meteors. The inner planets are small and rocky while the outer planets are large and gaseous.
The Solar System formed approximately 4.6 billion years ago from the collapse of a giant molecular cloud. It consists mainly of the Sun and eight planets that orbit it. The four inner terrestrial planets are composed of rock and metal, while the four outer gas giants are substantially larger and composed of hydrogen, helium, and ices. Other objects in the Solar System include dwarf planets, moons, asteroids, and comets. The Sun contains over 99% of the mass in the entire system.
The document provides details about the composition and formation of the solar system. It can be summarized as follows:
1) The solar system formed from the gravitational collapse of part of a large cloud of gas and dust known as the solar nebula. This led to the formation of the Sun and a protoplanetary disk surrounding it.
2) As the Sun formed and began generating heat, the protoplanetary disk flattened into a plane and began to condense, resulting in the formation of the planets, asteroids, comets and other bodies that make up the solar system.
3) Over time, scientific understanding of solar system formation has progressed from early hypotheses to the current nebular model, which views
1. The Sun is located at the center of our Solar System and is made up of hydrogen and helium.
2. It has a four-part structure including the core, photosphere, chromosphere, and corona, with temperatures ranging from 15 million degrees Celsius at its core to over 1 million degrees in its corona.
3. The Sun generates energy through nuclear fusion reactions at its core and exhibits phenomena like solar flares, prominences, and sunspots on its surface controlled by its magnetic field.
Comets are small cosmic bodies composed of rock, dust, ice and frozen gases that orbit the sun in elongated orbits. They develop tails and comas as solar radiation causes particles to dissipate from the comet as they approach the sun. Asteroids are small rocky bodies that orbit the sun and are remnants of larger planetesimals. Meteoroids are smaller particles that orbit the sun and create visible meteors when entering Earth's atmosphere due to pressure.
Comets are small cosmic bodies composed of rock, dust, ice and frozen gases that orbit the sun in elongated orbits. They develop tails and comas as solar radiation causes particles to dissipate from the comet as they approach the sun. Asteroids are small rocky bodies that orbit the sun and are remnants of larger planetesimals. Meteoroids are smaller particles that orbit the sun and create visible meteors when entering Earth's atmosphere due to pressure.
The Sun dominates the solar system, accounting for 99.86% of its total mass. There are eight planets that orbit the Sun - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The inner planets are rocky, while the outer planets are gaseous. The planets vary in their distances from the Sun, sizes, temperatures, and orbital periods. Earth is the only known planet capable of supporting life.
The document provides information about the solar system and beyond. It summarizes that the solar system consists of the Sun and objects that orbit it, including 8 planets. It is located within the Milky Way galaxy, which contains many stars, dust and gas. The document then provides details about the properties of objects in the solar system like planets, moons, asteroids and comets.
1) Our solar system is located in the Milky Way Galaxy, which contains 200 billion stars.
2) Spiral galaxies have a central dense area and spiraling arms where stars often form. There are two types of spiral galaxies.
3) Our solar system consists of the sun and objects that orbit it like planets, moons, asteroids, comets, and meteors. The inner planets are small and rocky while the outer planets are large and gaseous.
The Solar System formed approximately 4.6 billion years ago from the collapse of a giant molecular cloud. It consists mainly of the Sun and eight planets that orbit it. The four inner terrestrial planets are composed of rock and metal, while the four outer gas giants are substantially larger and composed of hydrogen, helium, and ices. Other objects in the Solar System include dwarf planets, moons, asteroids, and comets. The Sun contains over 99% of the mass in the entire system.
The document provides details about the composition and formation of the solar system. It can be summarized as follows:
1) The solar system formed from the gravitational collapse of part of a large cloud of gas and dust known as the solar nebula. This led to the formation of the Sun and a protoplanetary disk surrounding it.
2) As the Sun formed and began generating heat, the protoplanetary disk flattened into a plane and began to condense, resulting in the formation of the planets, asteroids, comets and other bodies that make up the solar system.
3) Over time, scientific understanding of solar system formation has progressed from early hypotheses to the current nebular model, which views
1. The Sun is located at the center of our Solar System and is made up of hydrogen and helium.
2. It has a four-part structure including the core, photosphere, chromosphere, and corona, with temperatures ranging from 15 million degrees Celsius at its core to over 1 million degrees in its corona.
3. The Sun generates energy through nuclear fusion reactions at its core and exhibits phenomena like solar flares, prominences, and sunspots on its surface controlled by its magnetic field.
Comets are small cosmic bodies composed of rock, dust, ice and frozen gases that orbit the sun in elongated orbits. They develop tails and comas as solar radiation causes particles to dissipate from the comet as they approach the sun. Asteroids are small rocky bodies that orbit the sun and are remnants of larger planetesimals. Meteoroids are smaller particles that orbit the sun and create visible meteors when entering Earth's atmosphere due to pressure.
Comets are small cosmic bodies composed of rock, dust, ice and frozen gases that orbit the sun in elongated orbits. They develop tails and comas as solar radiation causes particles to dissipate from the comet as they approach the sun. Asteroids are small rocky bodies that orbit the sun and are remnants of larger planetesimals. Meteoroids are smaller particles that orbit the sun and create visible meteors when entering Earth's atmosphere due to pressure.
The Sun dominates the solar system, accounting for 99.86% of its total mass. There are eight planets that orbit the Sun - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The inner planets are rocky, while the outer planets are gaseous. The planets vary in their distances from the Sun, sizes, temperatures, and orbital periods. Earth is the only known planet capable of supporting life.
The Sun dominates the solar system, accounting for 99.86% of its total mass. There are 8 planets that orbit the Sun - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The inner planets are rocky, while the outer planets are gaseous. Planets differ in their distances from the Sun, sizes, temperatures, and orbital periods. Earth is the only known planet capable of supporting life.
The Sun is a middle-aged, average sized yellow star that is made up mostly of hydrogen and helium. It is about 4.6 billion years old and located 93 million miles from Earth. The Sun generates heat and light through nuclear fusion reactions in its core that convert hydrogen into helium. It is the center of our Solar System and contains over 99% of the mass in the entire system. The Solar System also includes eight official planets that orbit the Sun, along with dwarf planets, moons, asteroids, comets, and other small bodies.
The document discusses comets, asteroids, and meteors. It describes comets as icy dirtballs that originate in the outer solar system and develop tails as they warm near the sun. Their tails can stretch for millions of kilometers and are made of dust or ionized gas. Asteroids are rocky fragments left over from the formation of the solar system and most orbit between Mars and Jupiter. Meteors are small rocky particles from asteroids and comets that burn up in Earth's atmosphere, and meteorites are meteors that survive atmospheric entry.
1) The universe is made up of hundreds of billions of galaxies separated by enormous distances. Our galaxy, the Milky Way, belongs to a local group of about 30 galaxies including our nearest neighbor Andromeda.
2) Galaxies contain between 100,000 and 500 million stars. They are made up of gas and dust and can contain open star clusters and nebulae. Many stars have planetary systems like our solar system, with planets that orbit stars and may have moons.
3) The solar system formed 4.5 billion years ago from a nebula containing gas and dust. It is centered around the sun and contains 8 planets divided into inner terrestrial planets like Earth and outer gas giants like Jupiter, as well as
The document discusses the major components of the universe including galaxies, stars, planets, comets and asteroids. It describes the formation of the universe through the Big Bang theory and provides details on key astronomical objects like nebulae, supernovae and constellations. Furthermore, it outlines our solar system and important facts about bodies like the sun, Earth and dwarf planets. The document also covers China's plans to develop an artificial moon and sun through nuclear fusion experiments.
The document provides an overview of the solar system, including its name and composition. It describes the inner and outer planets, with details on each planet's characteristics such as size, composition, and moons. Additional celestial bodies like asteroids, meteoroids, comets, and dwarf planets are also summarized, including their properties and current known counts. The document contains a table comparing key attributes of the eight major planets.
This document provides a summary of key concepts in astronomy, including the universe, galaxies, stars, planets in our solar system, and important historical astronomers like Ptolemy, Copernicus, and Galileo. It describes how stars are born from nebulae and die, as well as concepts like nuclear fusion, main sequence, and how our sun will eventually die. Important terms are defined like nebulae, constellations, blue giants, and red dwarfs. Historical figures that advanced our understanding of astronomy are also summarized.
This chapter discusses the origin and evolution of the Earth and the solar system. It begins with an overview of the Big Bang theory for the origin of the universe and then describes the nebular hypothesis for the formation of the solar system from a primordial cloud of gas and dust. Key points include the differentiation of the Earth into a core, mantle and crust due to melting after accretion and the abundance of iron in the Earth's core versus the crust. The chapter also provides details about the different types of planets, asteroids, comets and meteorites that make up the solar system.
The document discusses the universe and the solar system. It begins by explaining that the Big Bang occurred approximately 13.7 billion years ago and provides evidence for this theory. It then describes different models of the universe throughout history, from the geocentric to heliocentric models. The document also discusses the size of the universe, noting that galaxies are vast collections of stars, dust and gases that appear in clusters. Our galaxy is the Milky Way. It then provides details about the components of the solar system, including the sun, inner and outer planets, dwarf planets, asteroids, comets and moons.
This document provides information about astronomy and our solar system. It describes the different types of galaxies including spiral, elliptical, and irregular galaxies. It also discusses the inner and outer planets, with Mercury, Venus, Earth, and Mars as the terrestrial inner planets and Jupiter, Saturn, Uranus, and Neptune as the gaseous outer planets. Additionally, it covers stars, constellations, comets, and our place within the universe from the Milky Way galaxy to the Virgo Supercluster.
The document discusses the structure of the universe including galaxies, the Milky Way galaxy, and our solar system. It describes how galaxies are vast collections of stars, dust, and gases that appear in clusters. It also provides details about the shape of the Milky Way galaxy and explains that we cannot see it from Earth as shown in images. Additionally, it summarizes the major components of our solar system, including the sun, inner and outer planets, dwarf planets, and small bodies like asteroids and comets that orbit the sun.
A comprehensive study of Geography for PCS examination
This module is very helpful for the Students who are preparing for the Competitive Examination Like UPSC, BPSC & other State Public Service Commission.
This document contains information about meteors, meteorites, asteroids, and comets. It defines these terms and describes their differences. Meteoroids become meteors when entering Earth's atmosphere, and meteorites are meteors that survive impact with Earth's surface. Asteroids orbit the sun mainly between Mars and Jupiter. Comets have highly elliptical orbits and develop tails as they approach the sun due to sublimating ice. The document provides examples of meteor showers and observed fireballs.
1) The document discusses various celestial objects that orbit the sun including meteors, meteorites, asteroids, and comets. It provides definitions and descriptions of each object.
2) Key differences are outlined, such as meteoroids become meteors when entering the earth's atmosphere, and meteorites are meteors that survive impact and land on earth. Asteroids orbit mainly between Mars and Jupiter, while comets have more elliptical orbits and tails when near the sun.
3) Examples of significant meteors, asteroids, and comets are mentioned, including Comet Hale-Bopp which was exceptionally large and the longest observed comet.
The Milky Way galaxy is spiral in shape. We cannot see its spiral arms from Earth because we are located within the galaxy. The document discusses the history of models of the universe from the geocentric model of Ptolemy to the heliocentric model of Copernicus. It provides information about galaxies, our Milky Way galaxy, and describes the components that make up our solar system such as planets, dwarf planets, asteroids, comets and moons.
What is Solar system? FORMATION OF SOLAR SYSTEM. SOLAR SYSTEM: StructureUday Kumar Shil
The document summarizes the structure and components of the solar system. It describes:
1. The solar system formed from a large rotating cloud of gas and dust called the solar nebula approximately 4.6 billion years ago. As it contracted, the nebula flattened into a disk and kilometer-sized protoplanets began to form.
2. The solar system consists of the Sun and celestial objects bound to it by gravity, including eight planets composed of rock/metal or gas/hydrogen that orbit in nearly circular paths within the ecliptic plane.
3. Most planets have their own moons, and the gas giants have rings composed of tiny particles orbiting them. The solar system can be divided into
The document provides an overview of the universe and the solar system. It defines the universe as the space and time containing all matter and energy, governed by physical laws. The universe originated from the Big Bang around 13.7 billion years ago. It then describes the possible endings for the universe as the Big Crunch, Big Rip, Big Bounce, or Big Freeze. The rest of the document details the components that make up the solar system, including the planets, dwarf planets, asteroids, and other celestial bodies.
The document provides information about the sun and solar system. It describes the key layers of the sun's atmosphere, including the photosphere, chromosphere, and corona. It also classifies and compares the eight planets based on their size, composition, distance from the sun, rotation, and other characteristics. Additionally, it discusses asteroids, comets, and meteors, noting that asteroids reside in the belt between Mars and Jupiter, while comets have elliptical orbits and meteors appear as streaks of light in the night sky.
The document provides information about various objects in our solar system including asteroids, meteoroids, meteors, meteorites, comets, and the sun. It describes their composition, size, orbits, and how they interact with Earth's atmosphere in some cases. Key points are:
- Asteroids orbit between Mars and Jupiter and range in size from small rocks to objects 750km in diameter.
- Meteoroids are smaller than asteroids and become meteors when entering Earth's atmosphere, creating streaks of light. If they survive entry they are called meteorites.
- Comets have icy nuclei and tails made of vaporized gases. They orbit the sun in elliptical paths and are most visible when close to
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
The Sun dominates the solar system, accounting for 99.86% of its total mass. There are 8 planets that orbit the Sun - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The inner planets are rocky, while the outer planets are gaseous. Planets differ in their distances from the Sun, sizes, temperatures, and orbital periods. Earth is the only known planet capable of supporting life.
The Sun is a middle-aged, average sized yellow star that is made up mostly of hydrogen and helium. It is about 4.6 billion years old and located 93 million miles from Earth. The Sun generates heat and light through nuclear fusion reactions in its core that convert hydrogen into helium. It is the center of our Solar System and contains over 99% of the mass in the entire system. The Solar System also includes eight official planets that orbit the Sun, along with dwarf planets, moons, asteroids, comets, and other small bodies.
The document discusses comets, asteroids, and meteors. It describes comets as icy dirtballs that originate in the outer solar system and develop tails as they warm near the sun. Their tails can stretch for millions of kilometers and are made of dust or ionized gas. Asteroids are rocky fragments left over from the formation of the solar system and most orbit between Mars and Jupiter. Meteors are small rocky particles from asteroids and comets that burn up in Earth's atmosphere, and meteorites are meteors that survive atmospheric entry.
1) The universe is made up of hundreds of billions of galaxies separated by enormous distances. Our galaxy, the Milky Way, belongs to a local group of about 30 galaxies including our nearest neighbor Andromeda.
2) Galaxies contain between 100,000 and 500 million stars. They are made up of gas and dust and can contain open star clusters and nebulae. Many stars have planetary systems like our solar system, with planets that orbit stars and may have moons.
3) The solar system formed 4.5 billion years ago from a nebula containing gas and dust. It is centered around the sun and contains 8 planets divided into inner terrestrial planets like Earth and outer gas giants like Jupiter, as well as
The document discusses the major components of the universe including galaxies, stars, planets, comets and asteroids. It describes the formation of the universe through the Big Bang theory and provides details on key astronomical objects like nebulae, supernovae and constellations. Furthermore, it outlines our solar system and important facts about bodies like the sun, Earth and dwarf planets. The document also covers China's plans to develop an artificial moon and sun through nuclear fusion experiments.
The document provides an overview of the solar system, including its name and composition. It describes the inner and outer planets, with details on each planet's characteristics such as size, composition, and moons. Additional celestial bodies like asteroids, meteoroids, comets, and dwarf planets are also summarized, including their properties and current known counts. The document contains a table comparing key attributes of the eight major planets.
This document provides a summary of key concepts in astronomy, including the universe, galaxies, stars, planets in our solar system, and important historical astronomers like Ptolemy, Copernicus, and Galileo. It describes how stars are born from nebulae and die, as well as concepts like nuclear fusion, main sequence, and how our sun will eventually die. Important terms are defined like nebulae, constellations, blue giants, and red dwarfs. Historical figures that advanced our understanding of astronomy are also summarized.
This chapter discusses the origin and evolution of the Earth and the solar system. It begins with an overview of the Big Bang theory for the origin of the universe and then describes the nebular hypothesis for the formation of the solar system from a primordial cloud of gas and dust. Key points include the differentiation of the Earth into a core, mantle and crust due to melting after accretion and the abundance of iron in the Earth's core versus the crust. The chapter also provides details about the different types of planets, asteroids, comets and meteorites that make up the solar system.
The document discusses the universe and the solar system. It begins by explaining that the Big Bang occurred approximately 13.7 billion years ago and provides evidence for this theory. It then describes different models of the universe throughout history, from the geocentric to heliocentric models. The document also discusses the size of the universe, noting that galaxies are vast collections of stars, dust and gases that appear in clusters. Our galaxy is the Milky Way. It then provides details about the components of the solar system, including the sun, inner and outer planets, dwarf planets, asteroids, comets and moons.
This document provides information about astronomy and our solar system. It describes the different types of galaxies including spiral, elliptical, and irregular galaxies. It also discusses the inner and outer planets, with Mercury, Venus, Earth, and Mars as the terrestrial inner planets and Jupiter, Saturn, Uranus, and Neptune as the gaseous outer planets. Additionally, it covers stars, constellations, comets, and our place within the universe from the Milky Way galaxy to the Virgo Supercluster.
The document discusses the structure of the universe including galaxies, the Milky Way galaxy, and our solar system. It describes how galaxies are vast collections of stars, dust, and gases that appear in clusters. It also provides details about the shape of the Milky Way galaxy and explains that we cannot see it from Earth as shown in images. Additionally, it summarizes the major components of our solar system, including the sun, inner and outer planets, dwarf planets, and small bodies like asteroids and comets that orbit the sun.
A comprehensive study of Geography for PCS examination
This module is very helpful for the Students who are preparing for the Competitive Examination Like UPSC, BPSC & other State Public Service Commission.
This document contains information about meteors, meteorites, asteroids, and comets. It defines these terms and describes their differences. Meteoroids become meteors when entering Earth's atmosphere, and meteorites are meteors that survive impact with Earth's surface. Asteroids orbit the sun mainly between Mars and Jupiter. Comets have highly elliptical orbits and develop tails as they approach the sun due to sublimating ice. The document provides examples of meteor showers and observed fireballs.
1) The document discusses various celestial objects that orbit the sun including meteors, meteorites, asteroids, and comets. It provides definitions and descriptions of each object.
2) Key differences are outlined, such as meteoroids become meteors when entering the earth's atmosphere, and meteorites are meteors that survive impact and land on earth. Asteroids orbit mainly between Mars and Jupiter, while comets have more elliptical orbits and tails when near the sun.
3) Examples of significant meteors, asteroids, and comets are mentioned, including Comet Hale-Bopp which was exceptionally large and the longest observed comet.
The Milky Way galaxy is spiral in shape. We cannot see its spiral arms from Earth because we are located within the galaxy. The document discusses the history of models of the universe from the geocentric model of Ptolemy to the heliocentric model of Copernicus. It provides information about galaxies, our Milky Way galaxy, and describes the components that make up our solar system such as planets, dwarf planets, asteroids, comets and moons.
What is Solar system? FORMATION OF SOLAR SYSTEM. SOLAR SYSTEM: StructureUday Kumar Shil
The document summarizes the structure and components of the solar system. It describes:
1. The solar system formed from a large rotating cloud of gas and dust called the solar nebula approximately 4.6 billion years ago. As it contracted, the nebula flattened into a disk and kilometer-sized protoplanets began to form.
2. The solar system consists of the Sun and celestial objects bound to it by gravity, including eight planets composed of rock/metal or gas/hydrogen that orbit in nearly circular paths within the ecliptic plane.
3. Most planets have their own moons, and the gas giants have rings composed of tiny particles orbiting them. The solar system can be divided into
The document provides an overview of the universe and the solar system. It defines the universe as the space and time containing all matter and energy, governed by physical laws. The universe originated from the Big Bang around 13.7 billion years ago. It then describes the possible endings for the universe as the Big Crunch, Big Rip, Big Bounce, or Big Freeze. The rest of the document details the components that make up the solar system, including the planets, dwarf planets, asteroids, and other celestial bodies.
The document provides information about the sun and solar system. It describes the key layers of the sun's atmosphere, including the photosphere, chromosphere, and corona. It also classifies and compares the eight planets based on their size, composition, distance from the sun, rotation, and other characteristics. Additionally, it discusses asteroids, comets, and meteors, noting that asteroids reside in the belt between Mars and Jupiter, while comets have elliptical orbits and meteors appear as streaks of light in the night sky.
The document provides information about various objects in our solar system including asteroids, meteoroids, meteors, meteorites, comets, and the sun. It describes their composition, size, orbits, and how they interact with Earth's atmosphere in some cases. Key points are:
- Asteroids orbit between Mars and Jupiter and range in size from small rocks to objects 750km in diameter.
- Meteoroids are smaller than asteroids and become meteors when entering Earth's atmosphere, creating streaks of light. If they survive entry they are called meteorites.
- Comets have icy nuclei and tails made of vaporized gases. They orbit the sun in elliptical paths and are most visible when close to
Similar to Qwertyuiooasdfghjklzxcvbnm.1234566843345 (20)
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
SDSS1335+0728: The awakening of a ∼ 106M⊙ black hole⋆Sérgio Sacani
Context. The early-type galaxy SDSS J133519.91+072807.4 (hereafter SDSS1335+0728), which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Facility (ZTF) alert stream from December 2019 (as ZTF19acnskyy). This variability behaviour, coupled with the host-galaxy properties, suggests that SDSS1335+0728 hosts a ∼ 106M⊙ black hole (BH) that is currently in the process of ‘turning on’. Aims. We present a multi-wavelength photometric analysis and spectroscopic follow-up performed with the aim of better understanding the origin of the nuclear variations detected in SDSS1335+0728. Methods. We used archival photometry (from WISE, 2MASS, SDSS, GALEX, eROSITA) and spectroscopic data (from SDSS and LAMOST) to study the state of SDSS1335+0728 prior to December 2019, and new observations from Swift, SOAR/Goodman, VLT/X-shooter, and Keck/LRIS taken after its turn-on to characterise its current state. We analysed the variability of SDSS1335+0728 in the X-ray/UV/optical/mid-infrared range, modelled its spectral energy distribution prior to and after December 2019, and studied the evolution of its UV/optical spectra. Results. From our multi-wavelength photometric analysis, we find that: (a) since 2021, the UV flux (from Swift/UVOT observations) is four times brighter than the flux reported by GALEX in 2004; (b) since June 2022, the mid-infrared flux has risen more than two times, and the W1−W2 WISE colour has become redder; and (c) since February 2024, the source has begun showing X-ray emission. From our spectroscopic follow-up, we see that (i) the narrow emission line ratios are now consistent with a more energetic ionising continuum; (ii) broad emission lines are not detected; and (iii) the [OIII] line increased its flux ∼ 3.6 years after the first ZTF alert, which implies a relatively compact narrow-line-emitting region. Conclusions. We conclude that the variations observed in SDSS1335+0728 could be either explained by a ∼ 106M⊙ AGN that is just turning on or by an exotic tidal disruption event (TDE). If the former is true, SDSS1335+0728 is one of the strongest cases of an AGNobserved in the process of activating. If the latter were found to be the case, it would correspond to the longest and faintest TDE ever observed (or another class of still unknown nuclear transient). Future observations of SDSS1335+0728 are crucial to further understand its behaviour. Key words. galaxies: active– accretion, accretion discs– galaxies: individual: SDSS J133519.91+072807.4
PPT on Direct Seeded Rice presented at the three-day 'Training and Validation Workshop on Modules of Climate Smart Agriculture (CSA) Technologies in South Asia' workshop on April 22, 2024.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
The cost of acquiring information by natural selectionCarl Bergstrom
This is a short talk that I gave at the Banff International Research Station workshop on Modeling and Theory in Population Biology. The idea is to try to understand how the burden of natural selection relates to the amount of information that selection puts into the genome.
It's based on the first part of this research paper:
The cost of information acquisition by natural selection
Ryan Seamus McGee, Olivia Kosterlitz, Artem Kaznatcheev, Benjamin Kerr, Carl T. Bergstrom
bioRxiv 2022.07.02.498577; doi: https://doi.org/10.1101/2022.07.02.498577
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Sérgio Sacani
Context. The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty objects requires an explanation for the detection of compact Doppler-shifted Brγ emission. The ionized hydrogen in combination with the observation of mid-infrared L-band continuum emission suggests that most of these sources are embedded in a dusty envelope. These embedded sources are part of the S-cluster, and their relationship to the S-stars is still under debate. To date, the question of the origin of these two populations has been vague, although all explanations favor migration processes for the individual cluster members. Aims. This work revisits the S-cluster and its dusty members orbiting the supermassive black hole SgrA* on bound Keplerian orbits from a kinematic perspective. The aim is to explore the Keplerian parameters for patterns that might imply a nonrandom distribution of the sample. Additionally, various analytical aspects are considered to address the nature of the dusty sources. Methods. Based on the photometric analysis, we estimated the individual H−K and K−L colors for the source sample and compared the results to known cluster members. The classification revealed a noticeable contrast between the S-stars and the dusty sources. To fit the flux-density distribution, we utilized the radiative transfer code HYPERION and implemented a young stellar object Class I model. We obtained the position angle from the Keplerian fit results; additionally, we analyzed the distribution of the inclinations and the longitudes of the ascending node. Results. The colors of the dusty sources suggest a stellar nature consistent with the spectral energy distribution in the near and midinfrared domains. Furthermore, the evaporation timescales of dusty and gaseous clumps in the vicinity of SgrA* are much shorter ( 2yr) than the epochs covered by the observations (≈15yr). In addition to the strong evidence for the stellar classification of the D-sources, we also find a clear disk-like pattern following the arrangements of S-stars proposed in the literature. Furthermore, we find a global intrinsic inclination for all dusty sources of 60 ± 20◦, implying a common formation process. Conclusions. The pattern of the dusty sources manifested in the distribution of the position angles, inclinations, and longitudes of the ascending node strongly suggests two different scenarios: the main-sequence stars and the dusty stellar S-cluster sources share a common formation history or migrated with a similar formation channel in the vicinity of SgrA*. Alternatively, the gravitational influence of SgrA* in combination with a massive perturber, such as a putative intermediate mass black hole in the IRS 13 cluster, forces the dusty objects and S-stars to follow a particular orbital arrangement. Key words. stars: black holes– stars: formation– Galaxy: center– galaxies: star formation
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...Sérgio Sacani
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
−
27.82088
with a host spectroscopic redshift of
2.903
±
0.007
. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (
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(
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−
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∼
0.9
) despite a host galaxy with low-extinction and has a high Ca II velocity (
19
,
000
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2
,
000
km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-
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Ca-rich population. Although such an object is too red for any low-
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cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement (
≲
1
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) with
Λ
CDM. Therefore unlike low-
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Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
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truly diverge from their low-
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counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
Microbiology of Central Nervous System INFECTIONS.pdf
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1.
2. Qatar University
College of Arts and Sciences
Chemistry and Earth Sciences Department
Principles of General Geology - GEOL_101
Spring 2024
The Earth and Universe
3.
4. What is the universe?
How did the universe originate?
What is the fastest thing in the universe?
What is the solar system?
The Planet Earth
5. The Universe (Latin: universus) is all of space and time and their contents,
including all forms of matter and energy
Energy appears in the form of: light, heat, motion, or cosmic rays
Matter (solid, liquid, and gas) includes: galaxies that consist of
billions of stars in addition to planets, moons, comets, meteors, gas
clouds and dust clouds called nebulae
The Universe is everything we can touch, feel, sense, measure or detect. It
includes living things, planets, stars, galaxies, dust clouds, light, and even
time
What is The Universe?
So
6. Origin of the Universe
The Great Cloud
or
The Big Bang Theory
In the Big Bang theory, the universe began approximately 13.7 billion years
ago
An extremely dense, hot body of matter (All mass and energy in a single point)
expanded
The universe cooled
Atoms began to bond
Hydrogen formed H2 molecules - The fuel of stars
The simplest elements formed
Gravity caused formation of gaseous nebulae
Gravity gradually drew matter together to form the first stars and the first
galaxies
7.
8. Evidences for the Big Bang Theory
The universe is expanding from a central point
Hubble’s discovery in the 1920s of a relationship between a galaxy’s distance
from Earth and its speed
The entire universe has a pervasive and constant background radiation,
thought to be the faint afterglow of the Big Bang
The amount of hydrogen and helium gases in the universe
Photographing the remnants of the cosmic smoke resulting from the Big Bang
on the outskirts of the universe in 1989. There is an impression among
scientists that the amount of movement resulting from this explosion will run
out someday and that will inevitably lead to a reflection and turn the universe
into a fold according to what the theory of the great convergence assumes
9. Allah / God
Allah created the universe and the various processes driving physical and
biological evolution. These processes then resulted in the creation of galaxies,
our solar system, ……
Allah created life on Earth
Allah created everything
Who is the creator of Universe?
10. A galaxy is a huge collection of gas, dust, and billions of stars and their solar
systems
A galaxy is held together by gravity
The Universe contains billions of galaxies, each containing millions or billions
of stars, planets and asteroids, comets, meteors, gases, and solid and very
fine particles that are organized with each other in the universe
At the largest scale, galaxies are distributed uniformly and the same in all
directions, meaning that the universe has neither an edge nor a center
Galaxies differ and vary in size: some of them are small, consisting of only a
few million stars, some of them are of medium size, and some of them are
large, which contain more than 400 billion stars
Galaxies also differ in their shapes, some of which are spherical, semi-
spherical, disc, spiral, fusiform, elliptical or semi-elliptical. The disk shape is
the most widespread
Galaxies
11. What galaxy do we live in?
We live in one of the arms of a large Spiral galaxy called the Milky Way. The
Sun and its planets (including Earth) lie in this quiet part of the galaxy, about
half way out from the center
The Milky Way is the galaxy that contains our Solar System, with the name
describing the galaxy's appearance from Earth: a hazy band of light seen in
the night sky formed from stars that cannot be individually distinguished by
the naked eye
Radius: 52,850 light years
Age: 13.51 billion years
Escape velocity: 550 km/s
Number of stars: 100-400 billion
Distance: 25.6–27.1 kly (7.86–8.32 kpc)
Constellations: Orion, Sagittarius, Scorpius, Carina, Ara
Our galaxy, the Milky Way, also has a supermassive black hole in the middle
The Milky Way Galaxy
13. Light Year
The light-year is a unit of length used to express astronomical distances and
is equivalent to about 9.46 trillion kilometers or 5.88 trillion miles
As defined by the International Astronomical Union, a light-year is the
distance that light travels in vacuum in one Julian year
The speed of light in vacuum, commonly denoted c, is a universal physical
constant important in many areas of physics. Its exact value is defined as
299792458 meters per second (~ 300000 km per second)
14. Stars are immense balls of incandescent gas held together by gravity
The central core of a star is extremely hot and produces energy. Some
of this energy is released as visible light, which makes the star glow
Stars come in different sizes, colors, and temperatures. Our Sun, the
center of our solar system, is a yellow star of average temperature and
size
The surface temperatures of stars are very high, reaching 30,000 ° C in
some species, and their internal temperatures reach millions of
degrees
The stars appear in the sky in the form of bright points, and the reason
for this is that they are far away from the surface of the earth
Gravity binds stars together into vast galaxies
Stars
15. Nebula
A nebula is a giant cloud of dust and gas (hydrogen gas, helium gas and other
ionized gases) in space
Some nebulae (more than one nebula) come from the gas and dust thrown out
by the explosion of a dying star, such as a supernova. Other nebulae are
regions where new stars are beginning to form
The main difference between galaxies and nebulae are an extreme difference in
size, as well as their basic structure. A nebula is a cloud of dust and gas,
usually tens to hundreds of light years across. A galaxy is much larger —
usually thousands to hundreds of thousands of light years across
16. Planets
Planets are large, opaque celestial bodies orbiting a star (the Sun)
are smaller than a star but larger than an asteroid
Do not produce their own light but are illuminated by light from the stars
around which they revolves
Have sufficient mass to give them a spherical shape
Are alone in their orbits (have cleared their neighborhood of other objects)
Moons
Are solid dark bodies locked in orbit around a planet
Moons follow the planets and revolve in their orbits
Do not emit light, but can reflect light from the nearest star
17. Asteroids
Asteroids, sometimes called minor planets, are rocky, airless remnants left
over from the early formation of our solar system about 4.6 billion years ago
Most of this ancient space rubble can be found orbiting the Sun between Mars
and Jupiter within the main asteroid belt
Asteroids range in size from Vesta — the largest at about 329 miles (530
kilometers) in diameter — to bodies that are less than 33 feet (10 meters)
across
The total mass of all the asteroids combined is less than that of Earth's Moon
18. Comets
Comets are cosmic snowballs of frozen gases (Methane and Ammonia), rock
and dust that orbit the Sun. When frozen, they are the size of a small town
Comets are frozen leftovers from the formation of the solar system
When a comet's orbit brings it close to the Sun, it heats up and spews dust
and gases into a giant glowing head larger than most planets. The dust and
gases form a tail that stretches away from the Sun for millions of miles
There are likely billions of comets orbiting our Sunin the Kuiper Belt and even
more distant Oort Cloud
19. Meteoroids, Meteors & Meteorites
They’re all related to the flashes of light called “shooting stars” sometimes
seen streaking across the sky. But we call the same object by different names,
depending on where it is
Meteoroids are objects in space that range in size from dust grains to small
asteroids. Think of them as “space rocks.“ This term only applies when they’re
in space
Most are pieces of other, larger bodies that have been broken or blasted off.
Some come from comets, others from asteroids, and some even come from
the Moon and other planets
Some meteoroids are rocky, while others are metallic, or combinations of rock
and metal
20. Type of Meteorites
When meteoroids enter Earth’s atmosphere (or that of another planet, like
Mars) at high speed and burn up, the fireballs or “shooting stars” are called
meteors
When a meteoroid survives a trip through the atmosphere and hits the ground,
it’s called a meteorite
Meteorites may resemble Earth rocks, but they usually have a burned exterior
that can appear shiny. This “fusion crust” forms as the meteorite’s outer
surface melts while passing through the atmosphere.
There are three major types of meteorites: the "irons," the "stonys," and the
stony-irons. Although the majority of meteorites that fall to Earth are stony,
most of the meteorites discovered long after they fall are irons. Irons are
heavier and easier to distinguish from Earth rocks than stony meteorites
21. IRON METEORITES: Iron meteorites are made up of pure nickel and iron metal
with some impurities such as graphite and the mineral troilite
STONY METEORITES: Stony meteorites are meteorites made of rock, but can
also contain small amounts of iron. There are two types of stony meteorites;
chondrites and a chondrites
STONY-IRON METEORITES: Stony-Iron meteorites are almost even mixes of
both metallic and rocky material
23. The Solar System
The Solar System is the gravitationally bound system of the Sun and the
objects that orbit it, either directly or indirectly
Of the objects that orbit the Sun directly, the largest are the eight/nine planets,
with the remainder being smaller objects, the dwarf planets and small Solar
System bodies
Solar system: A sun, planets, moons and other objects
The solar system also includes asteroids and comets
The shape of the solar system is elliptical and consists of stars (the most
famous of which is the sun), planets, moons, asteroids, meteors, comets,
nebulae, gases and suspended fine materials
It is part of the Milky Way galaxy. The sun is thirty thousand light years away
from the center of the galaxy
This group formed about 4.6 billion years ago
25. The Sun
The Sun is the largest object within our solar system, comprising 99.8% of the
system's mass. The Sun is located at the center of our solar system, and
Earth orbits 93 million miles away from it. Though massive, the Sun still isn't
as large as other types of stars. It's classified as a yellow dwarf star
A yellow star of medium size, which is very close to the Earth, so it can be
studied accurately and the results of this study can be used to explain many
astronomical observations on other stars
The sun is a luminous body rotating around itself at a speed of 220 km / s,
and completing one revolution around its center in a period of time of 200
million years and can contain inside it 1,300,000 objects the size of the Earth
The surface temperature of the sun reaches about 5700 degrees Celsius, the
interior temperature reaches 14 million degrees Celsius, and the pressure
reaches one billion air pressure. Most of the earth's heat is from the sun
Our sun is one of 300 billion stars in the Milky Way
26.
27. Planets of the Solar System
There are eight planets in the Solar System according to the IAU definition. In
order of increasing distance from the Sun, they are the four terrestrials,
Mercury, Venus, Earth, and Mars, then the four giant planets, Jupiter, Saturn,
Uranus, and Neptune
The order of the planets in the solar system, starting nearest the sun and
working outward is the following: Mercury, Venus, Earth, Mars, Jupiter,
Saturn, Uranus, Neptune and then the possible Planet Nine. If you insist on
including Pluto, it would come after Neptune on the list
28. Planets of the Solar System
They are the planets close to the sun and include Mercury, Venus, Earth and
Mars
They are relatively small and made up mainly of rocks and minerals
1. Terrestrials or Inner planets or rocky dwarves
2. Outer planets or Gas Giants
They are the planets far away from the sun and include Jupiter, Saturn,
Uranus, Neptune and Pluto
They are large planets except for Pluto
They are often composed of light gases with a small rocky core
All the planets revolve around the sun in a
counterclockwise direction
29. Moons or natural satellites of the Solar System
Up first are Mercury and Venus. Neither of them has a moon
A lot of moons or no moons at all?
Mercury and Venus
We on Earth have just one moon, but some planets have dozens of them. Others
don’t have any
Which planets have moons, and which don’t?
Let’s go in order from the Sun
Up next is Earth, and of course we have one confirmed moon
Earth (That's us!)
Mars has two moons
Mars
30. Uranus has 27 moons that we know of. Some of them are half made of ice
Uranus
Lastly, Neptune has 14 named moons. One of Neptune's moons, Triton, is as
big as dwarf planet Pluto
Neptune
Next are the giant outer planets. They have lots of moons. Jupiter, for instance,
has 79 moons! (53 confirmed and 26 provisional)
These moons are so big you can see them with just a pair of binoculars
Jupiter
Saturn has 53 moons that have been named
Saturn also has 29 moons awaiting confirmation. They’re unconfirmed
because we’re waiting to get more information about them. If all of these
moons get confirmed, Saturn will have 82 moons. And that’s not counting
Saturn’s beautiful rings
Saturn
31.
32.
33. Moon of the Earth
The Moon is Earth’s only natural satellite and the fifth largest moon in the solar
system
The Moon’s presence helps stabilize our planet’s wobble, which helps stabilize
our climate
The Moon’s distance from Earth is about 240,000 miles (385,000km)
Earth's Moon is the only place beyond Earth where humans have set foot
The brightest and largest object in our night sky
The Moon was likely formed after a Mars-sized body collided with Earth
The Moon causes tides
The Moon has a very thin atmosphere called an exosphere
The Moon’s entire surface is cratered and pitted from impacts
35. Motion of the Moon around the Earth
The motion of the moon around the Earth is called Revolution
A sidereal month is the time it takes the Moon to complete one orbit around
Earth. This takes, on average, 27.3 days
A lunar month is the time it takes the Moon to pass through all of the Moon
phases, measured from one New Moon to the next New Moon. This takes, on
average, 29.53 days
36. Phases or Cycles of the Moon
The phases of the Moon are the different ways the Moon looks from Earth over
about a month
As the Moon orbits around the Earth, the half of the Moon that faces the Sun
will be lit up
The different shapes of the lit portion of the Moon that can be seen from Earth
are known as phases of the Moon
The difference in the shape of the moon (crescent, hump, or full moon) is due
to the light falling on its half facing the sun and the angle of its position with
respect to us inhabitants of the earth (the angle at which we see the part on
which the light falls
The half facing the sun is always luminous, so if the moon moves in its orbit
around the earth, then a small part of its luminous part begins to appear in the
form of a crescent and then increases day after day until the entire bright part
is facing us and we see it as a full moon, and this is after 14 days of The
movement of the moon began and then gradually diminishes until it
disappears after another 14 days of being full and thus has completed its cycle
37. What causes the phases of the moon to
change each night?
The phases of the moon are the changes in the amount of the surface of the
moon that are lit up over the course of a month, as viewed from earth
Because the positions of the Earth, Moon, and Sun vary throughout the course
of the month, the amount of the moon's surface that we can see changes a
little bit every night
38. Eclipse
An eclipse is an astronomical event. It is when one object in the sky moves
into the shadow of another such object
The term eclipse is most often used to describe a solar eclipse, when the
Moon's shadow crosses the Earth's surface, or a lunar eclipse, when the Moon
moves into the shadow of Earth
Solar Eclipse Lunar Eclipse
39. Earth is a terrestrial planet. It is small and rocky
Earth shares the solar system with 7 or 8 planets
Earth, our home, is the third planet from the sun. It's the only planet known to
have an atmosphere containing free oxygen, oceans of water on its surface
and, of course, life
Earth is the fifth largest of the planets in the solar system. It's smaller than the
four gas giants — Jupiter, Saturn, Uranus and Neptune — but larger than the
three other rocky planets, Mercury, Mars and Venus
The Earth is the densest planet in the Solar System
Earth has a diameter of roughly 8,000 miles (13,000 kilometers) and is round
because gravity pulls matter into a ball. But, it's not perfectly round. Earth is
really an "oblate spheroid," because its spin causes it to be squashed at its
poles and swollen at the equator
The Planet Earth
40. Earth has a powerful Gravitational Force
Earth has a powerful Centrifugal Force
Earth has a powerful Magnetic Force
The Earth's Molten Iron Core Creates a Magnetic Field
The Earth's surface is actually a combination of gravitational and centrifugal
forces
Water covers roughly 71 percent of Earth's surface, and most of that is in the
oceans. About a fifth of Earth's atmosphere consists of oxygen, produced by
plants
41. While Earth orbits the sun, the planet is simultaneously spinning on an
imaginary line called an axis that runs from the North Pole to the South Pole. It
takes Earth 23.934 hours to complete a rotation on its axis (resulting in day
and night) and 365.26 days to complete an orbit around the sun (resulting in
the seasons)
Earth rotates around its own axis Counterclockwise in the North Pole and
Clockwise in the South Pole
Earth's axis of rotation is tilted in relation to the ecliptic plane, an imaginary
surface through the planet's orbit around the sun. This means the Northern
and Southern hemispheres will sometimes point toward or away from the sun
depending on the time of year, and this changes the amount of light the
hemispheres receive, resulting in the seasons
Earth's orbit
42. Average distance from the sun: 92,956,050 miles (149,598,262 km)
Perihelion (closest approach to the sun): 91,402,640 miles (147,098,291 km)
Aphelion (farthest distance from the sun): 94,509,460 miles (152,098,233 km)
Length of solar day (single rotation on its axis): 23.934 hours
Length of year (single revolution around the sun): 365.26 days
Equatorial inclination to orbit: 23.4393 degrees
Statistics about Earth's orbit,
according to NASA:
43. GEO-SPHERES
The area near the surface of the earth can be divided into Five inter-connected
"geo-spheres:" the atmosphere, hydrosphere, lithosphere, magnetosphere,
and the biosphere
44.
45. Centrifugal force is an outward force
The Earth acquired this property as a result of the Earth's rapid rotation
around its axis
Since Earth rotates around a fixed axis, the direction of centrifugal force is
always outward away from the axis. Thus it is opposite to the direction of
gravity at the equator; at Earth's poles it is zero
This property expels the components of the planet from the center to the
outside, which is why it is called the centrifugal force. It works against the
force of gravity that attracts objects towards the center
The centrifugal force is small at the poles of the globe and large at the equator
The Earth's surface is actually a combination of gravitational and centrifugal
forces
Centrifugal Force
46. Gravity is the force of attracting objects towards the earth so that the masses
of objects tend to fall on the surface of the earth with the same force that
gravity produces
Gravity is not a property of the earth alone. In fact, every object in the
universe exerts force on every other object (So, there is gravity on jupiter and
other planets). This force is known as the gravitational force
Gravity controls all components of the universe, including the Earth. All the
planets of the solar system remain in their orbits by the force of attraction
between them and the sun
The earth is unique in its ability to attract objects located within the
gravitational field towards its center and therefore this property is attributed
to the earth exclusively and the spherical shape of the earth results from the
earth's attraction to all its constituent parts to the inside
Gravitational Force
47. The Earth acts like a huge magnet. Other planets do not have this property
Like a bar magnet, Earth has a dipolar magnetic field
Magnetic field lines flow from N to S and
Extend into space and weaken with distance from Earth
Create a shield around Earth (the magnetosphere)
The magnetosphere is the region above the ionosphere that is defined by the
extent of the Earth's magnetic field in space. It extends several tens of
thousands of kilometers into space, protecting the Earth from the charged
particles of the solar wind and cosmic rays that would otherwise strip away
the upper atmosphere, including the ozone layer that protects the Earth from
the harmful ultraviolet radiation
Magnetic Force
48. If we put a free-moving magnetic needle, it takes a position parallel to the
Earth's magnetic field, meaning it indicates the magnetic north and south. The
magnetic north and south do not coincide with the geographic north and
south. There is an angle between them called: the angle of magnetic
declination and is equal to 11.5 degrees
Magnetic Declination
49. The magnetic field is generated by electric currents due to the motion of
convection currents of a mixture of molten iron and nickel in the Earth's outer
core: these convection currents are caused by heat escaping from the core, a
natural process called a geodynamo
Therefore, the earth works as if it is a large electric generator, where electrical
currents are generated as a result of the mechanical energy resulting from the
rapid rotation of the earth around its axis and the convection currents in its
outer core and concomitant magnetic energy generation
This will be discussed in detail later when we study the interior of the Earth
Generation of the Magnetic Field
