This document discusses debris in our solar system and its importance in understanding the origin and evolution of the early solar system. It provides an overview of asteroids, meteorites, comets, and impact craters on Earth. Evidence suggests an asteroid or comet impact was responsible for the extinction of dinosaurs 65 million years ago. The study of solar system debris holds keys to deciphering the history of our solar system.
Meteoroids are solid objects that orbit the sun. When they enter the Earth's atmosphere, they heat up and produce bright streaks called meteors. Meteors originate from within our solar system, such as from the asteroid belt between Mars and Jupiter. Meteor showers occur when streams of meteoroids enter the atmosphere parallel to each other, radiating from a single point in the night sky. Common meteor showers include the Quadrantids in January, Lyrids in April, and Geminids in December.
Asteroids orbit the sun and are smaller than planets but larger than meteoroids. They formed in the asteroid belt between Mars and Jupiter but gravitational forces prevented them from forming a planet. Meteorites originate from asteroids and comets and survive atmospheric entry and impact, appearing as meteors and shooting stars. Ceres was the first asteroid discovered and is located in the asteroid belt, while asteroids can be classified based on their composition such as chondrites, achondrites, iron, and stony-iron meteorites.
The document discusses comets and provides key information about their composition, structure, and orbits. It notes that comets are mostly made up of ice and dust, forming tails when close to the sun. Comets can have either long or short orbital periods, with long-period comets originating from the distant Oort Cloud and short-period comets from the Kuiper Belt beyond Neptune. The nucleus and coma are identified as the main parts of a comet. Famous comets mentioned include Halley's Comet and Comets Hale-Bopp and Hyakutake.
Constellations are groups of stars that form imaginary patterns in the night sky. Different cultures have identified different shapes among the same stars. Historically, constellations were useful for navigation and keeping track of seasons. The North Star is particularly important for navigation in the Northern Hemisphere, while the Southern Cross serves a similar purpose in the Southern Hemisphere. Popular constellations represent myths and stories from different traditions around the world.
The document discusses the universe, galaxies, and the solar system. It begins by explaining that the universe contains everything that exists, but its size and boundaries are unknown. Galaxies are gravitationally bound systems of stars, gas and dust, such as the Milky Way galaxy. The solar system is located in the Milky Way and contains the Sun and objects that orbit it directly or indirectly, including planets, dwarf planets, asteroids and comets. Black holes are regions of spacetime where gravity is so strong that nothing can escape. The document then provides brief descriptions of asteroids, comets, meteorites and other astronomical objects that make up the observable universe.
Asteroids are small rocky or metallic bodies that orbit the sun and range in size from meters to over 500 km wide. They are found predominantly in the main asteroid belt between Mars and Jupiter. Ceres is the largest asteroid at 940 km in diameter. Asteroids are classified according to their composition, with C-type asteroids being the most common at 75% and consisting of carbon and dust. It is believed that an asteroid impact was responsible for the extinction of dinosaurs 65 million years ago.
A presentation on the planet Venus. Designed for 5th grade students. Contains basic facts, including the space probes that helped us learn about Venus. Includes quiz questions at the end.
The document provides an introduction to constellations visible in the night sky, including how to find them and their histories. It begins by explaining how people have observed patterns in the stars for millennia and then describes how to start identifying constellations such as the Big Dipper and Polaris. The rest of the document discusses specific constellations like Orion's Belt, Ursa Major, and zodiac signs including Taurus and Pisces. Brief summaries are given about the mythology and stories associated with each constellation.
Meteoroids are solid objects that orbit the sun. When they enter the Earth's atmosphere, they heat up and produce bright streaks called meteors. Meteors originate from within our solar system, such as from the asteroid belt between Mars and Jupiter. Meteor showers occur when streams of meteoroids enter the atmosphere parallel to each other, radiating from a single point in the night sky. Common meteor showers include the Quadrantids in January, Lyrids in April, and Geminids in December.
Asteroids orbit the sun and are smaller than planets but larger than meteoroids. They formed in the asteroid belt between Mars and Jupiter but gravitational forces prevented them from forming a planet. Meteorites originate from asteroids and comets and survive atmospheric entry and impact, appearing as meteors and shooting stars. Ceres was the first asteroid discovered and is located in the asteroid belt, while asteroids can be classified based on their composition such as chondrites, achondrites, iron, and stony-iron meteorites.
The document discusses comets and provides key information about their composition, structure, and orbits. It notes that comets are mostly made up of ice and dust, forming tails when close to the sun. Comets can have either long or short orbital periods, with long-period comets originating from the distant Oort Cloud and short-period comets from the Kuiper Belt beyond Neptune. The nucleus and coma are identified as the main parts of a comet. Famous comets mentioned include Halley's Comet and Comets Hale-Bopp and Hyakutake.
Constellations are groups of stars that form imaginary patterns in the night sky. Different cultures have identified different shapes among the same stars. Historically, constellations were useful for navigation and keeping track of seasons. The North Star is particularly important for navigation in the Northern Hemisphere, while the Southern Cross serves a similar purpose in the Southern Hemisphere. Popular constellations represent myths and stories from different traditions around the world.
The document discusses the universe, galaxies, and the solar system. It begins by explaining that the universe contains everything that exists, but its size and boundaries are unknown. Galaxies are gravitationally bound systems of stars, gas and dust, such as the Milky Way galaxy. The solar system is located in the Milky Way and contains the Sun and objects that orbit it directly or indirectly, including planets, dwarf planets, asteroids and comets. Black holes are regions of spacetime where gravity is so strong that nothing can escape. The document then provides brief descriptions of asteroids, comets, meteorites and other astronomical objects that make up the observable universe.
Asteroids are small rocky or metallic bodies that orbit the sun and range in size from meters to over 500 km wide. They are found predominantly in the main asteroid belt between Mars and Jupiter. Ceres is the largest asteroid at 940 km in diameter. Asteroids are classified according to their composition, with C-type asteroids being the most common at 75% and consisting of carbon and dust. It is believed that an asteroid impact was responsible for the extinction of dinosaurs 65 million years ago.
A presentation on the planet Venus. Designed for 5th grade students. Contains basic facts, including the space probes that helped us learn about Venus. Includes quiz questions at the end.
The document provides an introduction to constellations visible in the night sky, including how to find them and their histories. It begins by explaining how people have observed patterns in the stars for millennia and then describes how to start identifying constellations such as the Big Dipper and Polaris. The rest of the document discusses specific constellations like Orion's Belt, Ursa Major, and zodiac signs including Taurus and Pisces. Brief summaries are given about the mythology and stories associated with each constellation.
This document discusses dwarf planets in the solar system. It defines dwarf planets as celestial bodies that orbit the sun, are massive enough to be rounded by their own gravity, but have not cleared their orbit of other objects. It provides details on the five officially recognized dwarf planets: Ceres, Pluto, Eris, Haumea, and Makemake. It describes their sizes, compositions, orbits, and discoveries.
Asteroids are minor planets, especially those located in the inner Solar System. They are made up of rock and metals and are found predominantly in the asteroid belt between Mars and Jupiter. While small compared to Earth's moon, asteroids can be dangerous if they collide with Earth. The document provides details on the composition and types of asteroids, as well as some of the largest asteroids like Ceres and Pallas. It also discusses how studying asteroids can help us understand the origins of our solar system and life.
The document provides an overview of the structure and composition of the observed and non-observed universe. It discusses models that have been proposed to explain the universe, such as the Brahmanda, Aristotelian, Copernican, and Big Bang models. The observed universe consists of visible components like stars, galaxies, and clusters, as well as non-visible parts like microwaves, radio waves, and infrared radiation. It also describes the solar system and laws of physics relevant to cosmology like Hubble's law and Einstein's field equations. Finally, it notes that while normal matter makes up only 4% of the universe, non-observed dark matter and dark energy comprise 96% of the total composition.
The unaided human eye can see about 6,000 stars on a clear night, with about 3,000 stars visible at any given time. However, light pollution limits the number of visible stars to a few hundred for most locations. The apparent brightness of celestial objects is measured on the magnitude scale, with 1st magnitude stars being the brightest and 6th magnitude stars being the faintest visible to the unaided eye. Constellations help organize the sky into defined regions, though the stars within a constellation may be located at different distances.
This document discusses constellations from both a mythological and scientific perspective. It begins by defining constellations as groups of stars that appear to form patterns from Earth's point of view, though the stars are not physically close. Many constellations derive from figures in Greek mythology. The document then discusses how the night sky appears different depending on one's location and viewpoint. It concludes by noting that while constellations were meaningful for ancient cultures, modern astrophysics has revealed stars to be just a small part of a much larger universe.
The document summarizes key facts about the four inner planets of our solar system: Mercury, Venus, Earth, and Mars. It provides details on each planet's diameter, mass, density, atmosphere, distance from the sun, orbital path, moons, surface features, and core composition. Notably, it describes Mercury as the closest planet to the sun with no moons and a heavily cratered surface. Venus is similar in size to Earth but has a dense carbon dioxide atmosphere and retrograde rotation. Earth is unique in its liquid water and life. Mars has the largest volcano in the solar system called Olympus Mons and two small moons.
Comets are chunks of ice and dust that orbit the sun in elongated elliptical orbits, with a nucleus and coma forming the head and a tail always pointing away from the sun. Asteroids are smaller rocky objects found predominantly in the asteroid belt between Mars and Jupiter. Meteors are space rocks or dust that burn up as streaks of light upon entering Earth's atmosphere, with meteorites being those that survive impact with the surface.
The document summarizes key facts about our solar system. It begins by listing the order of the planets - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. It notes that an asteroid belt separates the inner planets of Mercury, Venus, Earth and Mars from the outer planets of Jupiter, Saturn, Uranus and Neptune. It also identifies three dwarf planets: Ceres, Pluto and Eris. Key details provided include that Earth is the only known habitable planet, Venus has dense clouds of sulfuric acid, and Jupiter is the largest planet with over 60 moons.
Astronomy is the scientific study of objects and matter beyond Earth's atmosphere. There are four main types of astronomy: astrophysics, astrometry, astrogeology, and astrobiology. Astronomers study the origin and workings of the universe and its objects. Some core subjects in astronomy include physics, mathematics, quantum mechanics, and electromagnetic waves. To become an astronomer requires at least a bachelor's degree in astronomy, physics, or a related field, which provides the necessary scientific skills and knowledge. Astronomy involves scientific observation and study, whereas astrology involves the belief that the positions of the stars and planets can affect human lives.
Asteroids are rocky and metallic objects that orbit the sun but are too small to be considered planets. They have diverse compositions and shapes, ranging from nearly spherical to very irregular. They are classified based on their composition as determined from spectral analysis and similarities to known meteorites. Asteroids can be found in the asteroid belt between Mars and Jupiter, as well as in near-Earth orbits such as the Amor, Apollo, Aten, and Trojan groups.
- The Galileo probe explored Jupiter and its moons from 1995-2003, discovering evidence of subsurface oceans on Europa and volcanic activity on Io. It was the first spacecraft to fly by an asteroid and discover a moon orbiting an asteroid.
- Col. Eileen Collins was the first female shuttle commander, commanding missions STS-93 in 1999 and STS-114 in 2005. She has logged over 872 hours in space.
- The Mars Pathfinder mission in 1997 proved that a rover could be placed on Mars cheaply, sending back over 17,000 photos and 15 chemical analyses before ending in 1997.
This document discusses how the spectral classification of stars can reveal information about their composition and temperature. It explains that stars are classified into seven main categories (O, B, A, F, G, K, M) based on their absorption spectra, with O being the hottest and M being the coolest. Each class is associated with a range of surface temperatures and colors. By analyzing a star's spectrum, astronomers can determine what chemical elements are present in its atmosphere and measure its temperature, allowing insights into its composition and properties.
A meteor is a streak of light seen in the sky when a meteoroid (a small rocky fragment from an asteroid or comet) burns up upon entering Earth's atmosphere. Meteoroids are broken up rocks and dust that originate from comets, asteroids, the Moon, or Mars. When a meteoroid enters the atmosphere, the air in front of it heats up and causes the meteoroid to burn up. If a fragment survives the fiery entry and reaches the ground, it is then called a meteorite.
The document discusses constellations, which are patterns of stars recognized by various ancient cultures and formally defined by the IAU. Constellations were used for navigation, tracking seasons, and preserving myths. The IAU recognizes 88 constellations that fall within designated boundaries and include a variety of figures from mythology and science. Smaller unofficial patterns within constellations are called asterisms. Six constellations in the northern sky are always visible from a latitude of 28 degrees north.
This document provides an overview of the characteristics, classifications, motions, and significance of stars. It discusses their sizes, colors, temperatures, compositions, and magnitudes. Stars are classified based on their spectral types, which relate to their surface temperatures. The Hertzsprung-Russell diagram plots stars' luminosities and temperatures. Stars exhibit both apparent and actual motions, including proper motion across the sky. Studying stars helps us understand how elements are formed, how our solar system evolved, and the dynamics influencing galaxies.
Claudius Ptolemy was a 2nd century Greek astronomer whose contributions included compiling astronomical and geographical knowledge of the Roman Empire in his treatises Almagest, Geographia, and Tetrabiblos. In Almagest, he proposed the geocentric Ptolemaic system to explain planetary motions, using epicycles and eccentric circles to account for retrograde motion. This system placed the Earth at the center of the universe and remained the dominant model of astronomy for over 1,000 years until Copernicus proposed a heliocentric model. Ptolemy's Geographia also compiled geographical coordinates of the known world.
Asteroids, comets, and meteoroids are small rocky or icy bodies that orbit the sun. Thousands of asteroids orbit in the asteroid belt between Mars and Jupiter. Asteroids are remnants of early planet formation. Comets are composed of ice and dust and have highly elliptical orbits, forming tails as they near the sun due to heating. When meteoroids enter Earth's atmosphere, they burn up and are seen as meteors or shooting stars. Those that survive are called meteorites and sometimes leave impact craters. Analysis of meteorites provides clues about early solar system formation and even the origin of life.
A meteoroid is a small rocky or metallic object traveling through space. Most meteoroids range in size from small grains to 1 meter and are fragments from comets or asteroids. When meteoroids enter the Earth's atmosphere, friction and compression cause them to heat up and glow - appearing as "shooting stars" or meteors. If they survive atmospheric entry and reach the ground, they are called meteorites.
There are several types of galaxies including spiral, elliptical, irregular, and barred galaxies. Spiral galaxies are the most common type and have tightly or loosely wound spiral arms. The Milky Way is a typical spiral galaxy located in the outer range of the galaxy. Other galaxy types include whirlpool galaxies like M51a, barred galaxies like NGC 1365, and elliptical galaxies which can be very large or small dwarf galaxies. Irregular galaxies have no distinct shape.
The document discusses asteroids and meteorites. Asteroids are remnants of planetary formation in the solar system. They are classified based on composition and location in relation to gravitational resonances with Jupiter. Ceres is the largest asteroid and is now classified as a dwarf planet. Meteorites provide information about early solar system conditions. They are classified based on composition as iron, stony, or stony-iron meteorites. Carbonaceous chondrites contain organic compounds and water, indicating the early solar system environment allowed these to form. Meteorites can also originate from the Moon or Mars.
This document provides an overview of asteroids, including their sizes, where they are located, and where they come from. It discusses how asteroids are studied and examples of asteroid missions. The document addresses why asteroids are of interest and the different levels of impact threats they pose to Earth, from small localized impacts to large civilization-ending impacts. It provides statistics on impact frequencies and examples of impact effects. Finally, it discusses strategies that can be used to detect, deflect, or destroy asteroids to mitigate impact risks.
This document discusses dwarf planets in the solar system. It defines dwarf planets as celestial bodies that orbit the sun, are massive enough to be rounded by their own gravity, but have not cleared their orbit of other objects. It provides details on the five officially recognized dwarf planets: Ceres, Pluto, Eris, Haumea, and Makemake. It describes their sizes, compositions, orbits, and discoveries.
Asteroids are minor planets, especially those located in the inner Solar System. They are made up of rock and metals and are found predominantly in the asteroid belt between Mars and Jupiter. While small compared to Earth's moon, asteroids can be dangerous if they collide with Earth. The document provides details on the composition and types of asteroids, as well as some of the largest asteroids like Ceres and Pallas. It also discusses how studying asteroids can help us understand the origins of our solar system and life.
The document provides an overview of the structure and composition of the observed and non-observed universe. It discusses models that have been proposed to explain the universe, such as the Brahmanda, Aristotelian, Copernican, and Big Bang models. The observed universe consists of visible components like stars, galaxies, and clusters, as well as non-visible parts like microwaves, radio waves, and infrared radiation. It also describes the solar system and laws of physics relevant to cosmology like Hubble's law and Einstein's field equations. Finally, it notes that while normal matter makes up only 4% of the universe, non-observed dark matter and dark energy comprise 96% of the total composition.
The unaided human eye can see about 6,000 stars on a clear night, with about 3,000 stars visible at any given time. However, light pollution limits the number of visible stars to a few hundred for most locations. The apparent brightness of celestial objects is measured on the magnitude scale, with 1st magnitude stars being the brightest and 6th magnitude stars being the faintest visible to the unaided eye. Constellations help organize the sky into defined regions, though the stars within a constellation may be located at different distances.
This document discusses constellations from both a mythological and scientific perspective. It begins by defining constellations as groups of stars that appear to form patterns from Earth's point of view, though the stars are not physically close. Many constellations derive from figures in Greek mythology. The document then discusses how the night sky appears different depending on one's location and viewpoint. It concludes by noting that while constellations were meaningful for ancient cultures, modern astrophysics has revealed stars to be just a small part of a much larger universe.
The document summarizes key facts about the four inner planets of our solar system: Mercury, Venus, Earth, and Mars. It provides details on each planet's diameter, mass, density, atmosphere, distance from the sun, orbital path, moons, surface features, and core composition. Notably, it describes Mercury as the closest planet to the sun with no moons and a heavily cratered surface. Venus is similar in size to Earth but has a dense carbon dioxide atmosphere and retrograde rotation. Earth is unique in its liquid water and life. Mars has the largest volcano in the solar system called Olympus Mons and two small moons.
Comets are chunks of ice and dust that orbit the sun in elongated elliptical orbits, with a nucleus and coma forming the head and a tail always pointing away from the sun. Asteroids are smaller rocky objects found predominantly in the asteroid belt between Mars and Jupiter. Meteors are space rocks or dust that burn up as streaks of light upon entering Earth's atmosphere, with meteorites being those that survive impact with the surface.
The document summarizes key facts about our solar system. It begins by listing the order of the planets - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. It notes that an asteroid belt separates the inner planets of Mercury, Venus, Earth and Mars from the outer planets of Jupiter, Saturn, Uranus and Neptune. It also identifies three dwarf planets: Ceres, Pluto and Eris. Key details provided include that Earth is the only known habitable planet, Venus has dense clouds of sulfuric acid, and Jupiter is the largest planet with over 60 moons.
Astronomy is the scientific study of objects and matter beyond Earth's atmosphere. There are four main types of astronomy: astrophysics, astrometry, astrogeology, and astrobiology. Astronomers study the origin and workings of the universe and its objects. Some core subjects in astronomy include physics, mathematics, quantum mechanics, and electromagnetic waves. To become an astronomer requires at least a bachelor's degree in astronomy, physics, or a related field, which provides the necessary scientific skills and knowledge. Astronomy involves scientific observation and study, whereas astrology involves the belief that the positions of the stars and planets can affect human lives.
Asteroids are rocky and metallic objects that orbit the sun but are too small to be considered planets. They have diverse compositions and shapes, ranging from nearly spherical to very irregular. They are classified based on their composition as determined from spectral analysis and similarities to known meteorites. Asteroids can be found in the asteroid belt between Mars and Jupiter, as well as in near-Earth orbits such as the Amor, Apollo, Aten, and Trojan groups.
- The Galileo probe explored Jupiter and its moons from 1995-2003, discovering evidence of subsurface oceans on Europa and volcanic activity on Io. It was the first spacecraft to fly by an asteroid and discover a moon orbiting an asteroid.
- Col. Eileen Collins was the first female shuttle commander, commanding missions STS-93 in 1999 and STS-114 in 2005. She has logged over 872 hours in space.
- The Mars Pathfinder mission in 1997 proved that a rover could be placed on Mars cheaply, sending back over 17,000 photos and 15 chemical analyses before ending in 1997.
This document discusses how the spectral classification of stars can reveal information about their composition and temperature. It explains that stars are classified into seven main categories (O, B, A, F, G, K, M) based on their absorption spectra, with O being the hottest and M being the coolest. Each class is associated with a range of surface temperatures and colors. By analyzing a star's spectrum, astronomers can determine what chemical elements are present in its atmosphere and measure its temperature, allowing insights into its composition and properties.
A meteor is a streak of light seen in the sky when a meteoroid (a small rocky fragment from an asteroid or comet) burns up upon entering Earth's atmosphere. Meteoroids are broken up rocks and dust that originate from comets, asteroids, the Moon, or Mars. When a meteoroid enters the atmosphere, the air in front of it heats up and causes the meteoroid to burn up. If a fragment survives the fiery entry and reaches the ground, it is then called a meteorite.
The document discusses constellations, which are patterns of stars recognized by various ancient cultures and formally defined by the IAU. Constellations were used for navigation, tracking seasons, and preserving myths. The IAU recognizes 88 constellations that fall within designated boundaries and include a variety of figures from mythology and science. Smaller unofficial patterns within constellations are called asterisms. Six constellations in the northern sky are always visible from a latitude of 28 degrees north.
This document provides an overview of the characteristics, classifications, motions, and significance of stars. It discusses their sizes, colors, temperatures, compositions, and magnitudes. Stars are classified based on their spectral types, which relate to their surface temperatures. The Hertzsprung-Russell diagram plots stars' luminosities and temperatures. Stars exhibit both apparent and actual motions, including proper motion across the sky. Studying stars helps us understand how elements are formed, how our solar system evolved, and the dynamics influencing galaxies.
Claudius Ptolemy was a 2nd century Greek astronomer whose contributions included compiling astronomical and geographical knowledge of the Roman Empire in his treatises Almagest, Geographia, and Tetrabiblos. In Almagest, he proposed the geocentric Ptolemaic system to explain planetary motions, using epicycles and eccentric circles to account for retrograde motion. This system placed the Earth at the center of the universe and remained the dominant model of astronomy for over 1,000 years until Copernicus proposed a heliocentric model. Ptolemy's Geographia also compiled geographical coordinates of the known world.
Asteroids, comets, and meteoroids are small rocky or icy bodies that orbit the sun. Thousands of asteroids orbit in the asteroid belt between Mars and Jupiter. Asteroids are remnants of early planet formation. Comets are composed of ice and dust and have highly elliptical orbits, forming tails as they near the sun due to heating. When meteoroids enter Earth's atmosphere, they burn up and are seen as meteors or shooting stars. Those that survive are called meteorites and sometimes leave impact craters. Analysis of meteorites provides clues about early solar system formation and even the origin of life.
A meteoroid is a small rocky or metallic object traveling through space. Most meteoroids range in size from small grains to 1 meter and are fragments from comets or asteroids. When meteoroids enter the Earth's atmosphere, friction and compression cause them to heat up and glow - appearing as "shooting stars" or meteors. If they survive atmospheric entry and reach the ground, they are called meteorites.
There are several types of galaxies including spiral, elliptical, irregular, and barred galaxies. Spiral galaxies are the most common type and have tightly or loosely wound spiral arms. The Milky Way is a typical spiral galaxy located in the outer range of the galaxy. Other galaxy types include whirlpool galaxies like M51a, barred galaxies like NGC 1365, and elliptical galaxies which can be very large or small dwarf galaxies. Irregular galaxies have no distinct shape.
The document discusses asteroids and meteorites. Asteroids are remnants of planetary formation in the solar system. They are classified based on composition and location in relation to gravitational resonances with Jupiter. Ceres is the largest asteroid and is now classified as a dwarf planet. Meteorites provide information about early solar system conditions. They are classified based on composition as iron, stony, or stony-iron meteorites. Carbonaceous chondrites contain organic compounds and water, indicating the early solar system environment allowed these to form. Meteorites can also originate from the Moon or Mars.
This document provides an overview of asteroids, including their sizes, where they are located, and where they come from. It discusses how asteroids are studied and examples of asteroid missions. The document addresses why asteroids are of interest and the different levels of impact threats they pose to Earth, from small localized impacts to large civilization-ending impacts. It provides statistics on impact frequencies and examples of impact effects. Finally, it discusses strategies that can be used to detect, deflect, or destroy asteroids to mitigate impact risks.
This document provides information about comets and asteroids. It defines a comet as a small solar system body that displays a coma and sometimes tail when close to the sun due to solar radiation. Comet nuclei range from hundreds of meters to tens of kilometers and are made of ice, dust, and small rocks. The document discusses how Edmond Halley correctly hypothesized that the comets of 1456, 1532, 1607 and 1682 were the same object, now known as Halley's Comet, and how it returns every 75-76 years. It also mentions that the impact of a 10km asteroid may have caused the extinction of dinosaurs 65 million years ago based on geological evidence.
The document discusses comets, asteroids, meteors, and the differences between them. It provides information on their composition, orbits, and how they are formed. Comets are made of ice and dust that formed in the early solar system. Their tails always point away from the sun due to solar winds. Asteroids are large chunks of rock and metal left over from the formation of the planets. Meteors are small pieces of debris from asteroids and comets that burn up as they fall through the Earth's atmosphere, appearing as shooting stars.
Asteroids are minor planets located mainly in the inner Solar System between Mars and Jupiter. They range greatly in size, from almost 1000 km for the largest down to rocks just tens of meters across. Asteroids are composed of various materials like rock, metal, and ice, with some like Ceres having a rocky core and icy mantle. They become darker and redder over time due to space weathering. Exploration of asteroids began with early probes imaging Phobos and Deimos in 1971, but their shapes and terrain were unknown until the age of space travel.
This document summarizes the history of comet exploration. It describes how comets were initially seen as omens of disaster by ancient cultures but were later determined to follow predictable orbits by Halley. The 20th century saw significant advances in comet observation including spacecraft missions like Giotto, Stardust, Deep Impact and Rosetta that provided insights into comet composition and origins. Current theories suggest comets may have delivered water and organic molecules to early Earth. The most observed comet ever was ISON, intensely studied by spacecraft and ground telescopes in 2013 before disintegrating near the Sun.
Comets are balls of ice and dust that develop tails when approaching the sun. They are leftovers from the formation of the universe. Asteroids are small rocky objects leftover from the formation of the solar system between Mars and Jupiter. Meteoroids become meteors as they burn up in Earth's atmosphere, and meteorites if they reach the ground. The difference is meteoroids travel in space until entering the atmosphere, meteors are what we see as "shooting stars", and meteorites reach the ground.
Comets are icy counterparts to asteroids that formed beyond the frost line in the early solar system. They have a frozen nucleus and can grow comas and tails as they enter the inner solar system and warm. Comet showers occur when Earth crosses a comet's orbit and encounters dust ejected along its path. The Kuiper belt contains orderly comet orbits beyond Neptune, while the distant Oort cloud has randomly distributed comet orbits initially placed there by interactions with giant planets. Spacecraft images have revealed diverse geology on comet nuclei including cliffs, mesas, and circular depressions.
Comets are small icy objects with two tails made of gas and dust that formed over 4.6 billion years ago in the early solar system and have highly elliptical orbits. Asteroids are small rocky or metallic objects that orbit the sun, ranging in size from meters to hundreds of kilometers wide with irregular shapes and cratered surfaces. Meteors are streaks of light seen when meteoroids - space rocks or fragments that can be from comets, asteroids, moons or Mars - enter the Earth's atmosphere. Some meteoroids survive entry and land on Earth's surface as meteorites.
Comets and asteroids are remnants from the formation of the solar system. Comets originate from the Kuiper Belt and Oort Cloud and are icy bodies, while asteroids originate from the Main Asteroid Belt and are rocky fragments. Both have irregular shapes and sizes ranging from 1-100 km. Comets have highly elliptical orbits with periods of 75 years to millions of years, while asteroids have more rounded orbits with periods of 1-100 years. When a meteoroid from space enters the atmosphere, it becomes a meteor or "shooting star"; any fragments that reach the ground are called meteorites.
Asteroids are leftover pieces from the formation of the solar system and have been around for many years. Most asteroids are found in the asteroid belt, but some are scattered across space like Da14, a small asteroid that has lost its orbit and is set to amaze.
Recent advances in space technology have allowed scientists from different backgrounds to collaborate on studying Near-Earth Objects like comets and asteroids. Studies of these objects provide clues about the origins of the solar system. Several asteroids have been discovered to come close to Earth in recent years, including Asteroid 2012 DA14 in February 2012. Impacts from asteroids and comets have significantly affected Earth in the past, including possibly causing the extinction of dinosaurs 65 million years ago. On average, objects large enough for an impact are estimated to hit Earth once every 100,000 years or so, with smaller objects hitting more frequently.
Recent advances in space technology have allowed scientists from different fields to collaborate on studying Near-Earth Objects like comets and asteroids. Both comets and asteroids provide clues about the origins of our solar system. Several asteroids have been discovered to come close to Earth in recent years, including Asteroid 2012 DA14 which had a very close approach in February 2012. Impacts from asteroids and comets have affected Earth in the past and could cause catastrophic effects if a large one collided with Earth, though such collisions are rare.
Asteroids, comets, and meteors are celestial bodies that orbit the sun. Asteroids are rocky or metallic objects that orbit in the asteroid belt between Mars and Jupiter. Comets are icy bodies with long tails made of ice and dust that evaporate when near the sun. Meteors are solid objects that enter a planet's atmosphere and appear as "shooting stars."
Science 8 2nd Qtr Lesson 5 Asteroid and Comet.pptxMaricelYamat1
A solar system is composed of the Sun and objects that orbit around it, including planets, moons, asteroids, comets, and meteoroids. The eight major planets in order from the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Minor members of the solar system include asteroids, most of which orbit in the asteroid belt between Mars and Jupiter. Comets have highly elliptical orbits and are composed of dust and frozen gases. Meteoroids are small pieces of asteroids and comets that become meteors as they burn up entering Earth's atmosphere.
Asteroids are rocky objects that orbit the sun between Mars and Jupiter. They range in size from Ceres, which is about 1000 km in diameter, to pebbles. Most asteroids inhabit the asteroid belt between Mars and Jupiter, where they are thought to have formed from the leftover debris from planet formation. Some asteroids cross into Earth's orbit and are called Near-Earth Asteroids. Asteroids can be categorized by size, composition, and orbital location. They pose a threat to Earth if a large one were to impact, which could happen every 1000-10000 years on average. Asteroids differ from comets in that comets contain ice while asteroids are made of rock and metal. Meteoroids are smaller pieces of asteroids or
Eclipse and its types with asteroid comets and meteorites and black hole GCUF
This document presents information about eclipses, asteroids, comets, meteorites, and black holes. It discusses the history of eclipses dating back over 4000 years in China. It describes the two types of eclipses - lunar and solar eclipses. Asteroids are described as small planetary bodies that orbit the sun, ranging in size from 933km to only 6m in diameter. Comets contain an icy core with dust and release gas and particles as they orbit the sun. Meteorites are small pieces of debris from asteroids or comets that survive entering Earth's atmosphere. Black holes are regions with extremely strong gravitational fields that can absorb anything, even light.
1. The document is a presentation by Bharat Aggarwal on asteroids and comets.
2. It discusses how asteroids and comets formed in the early solar system and their orbits, with minor planets mostly located between Mars and Jupiter.
3. Comets formed farther out in the solar system and were flung outward by planetary encounters, while some became trapped in the inner solar system.
The document summarizes the terrestrial and Jovian planets of our solar system, as well as interplanetary debris. It describes the four terrestrial planets - Mercury, Venus, Earth, and Mars - as being made of rock and metal with solid surfaces. It then outlines the gas giants Jupiter and Saturn and ice giants Uranus and Neptune. The document concludes by defining asteroids, comets, and meteoroids as the three main types of interplanetary debris leftover from planetary formation.
Asteroids are small airless rocky bodies that orbit the sun but are too small to be considered planets. Most asteroids lie within the vast asteroid belt between the orbits of Mars and Jupiter. There are different types of asteroids classified based on their orbits, including those in the main asteroid belt and near-Earth asteroids whose orbits bring them closer to Earth.
About the different dwarf planets their location moons etc. What meteoroids , meteors, comet , asteroids etc. ? what and where oort cloud and Kuiper's belt?
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.
The Solar System formed from a large rotating cloud of gas and dust called a solar nebula. As the nebula condensed due to gravity, a central mass became the Sun and the remaining material formed rings that eventually became the planets. The Sun consists of an inner core where nuclear fusion occurs and surrounding layers including the photosphere, chromosphere, and corona. The eight major planets can be divided into terrestrial and Jovian planets. Smaller bodies like asteroids and comets also orbit the Sun.
Meteors are rocks that fly through the sky and sometimes produce meteor showers. Comets have a nucleus made of ice and dust surrounded by a coma and tail. Asteroids orbit the sun in a belt between Mars and Jupiter, and are believed to be remnants of larger planetary bodies.
Planetesimal ejection describes how leftover debris from the formation of the planets was captured as moons or ended up in the asteroid belt, Kuiper belt, or Oort cloud. Asteroids and meteoroids are small rocky or metallic objects found primarily in the inner solar system, with asteroids larger than 100 meters and meteoroids smaller. They orbit near the plane of the solar system in regions like the asteroid belt. When these objects enter the Earth's atmosphere, they appear as meteors and some survive impact as meteorites. Larger impacts are rarer but can cause global effects like the extinction of dinosaurs.
Comets, asteroids, meteoroids, and meteorites are different types of small solar system bodies. Comets are icy bodies that develop tails as they heat up when passing near the sun. Asteroids orbit the sun and most reside in the asteroid belt between Mars and Jupiter. Meteoroids are smaller objects that enter the earth's atmosphere and are called meteors when burning up in the sky. Those that survive entry and hit the ground are meteorites.
A lesson for grade 8 science. This tackles the the member of the solar system and some information about them. This is just a review from the other topics they have learned from grade 7. Hope this presentation helps someone.
The document discusses asteroids, comets, and meteorites. It states that asteroids and comets contain clues about the early solar system as they have changed little since formation 4.6 billion years ago. Asteroids are likely the fragmented remains of planetesimals that failed to form a planet due to Jupiter's gravity. Meteorites also likely formed from planetesimals and contain materials that predate the solar system. The document examines the different types of meteorites and asteroids based on their compositions.
The bright streak of light we see when a meteoroid enters our atmosphere is caused by frictional heating as the meteoroid speeds through the gases of our atmosphere. The correct answer is c.
The Solar System an volume of Space defined by the influence of the Sun gravity. It is extra-ordinary complex considered the type and the number of objects that circulate around the Sun. Our knowledge about the Solar System exploded as we started sending spacecrafts at the second half of the twentieth century. This is just a slideshow describing the major objects within the Solar System. 25 Sept 2021
Energy exists in various forms and can be transferred from one form to another but not created or destroyed. Work is the transfer of energy due to a force acting on an object over a distance. Kinetic energy is the energy of motion while potential energy is stored energy due to an object's position or composition. Chemical energy powers living things through photosynthesis and can be stored for later use. Nuclear energy is released through fusion in stars and fission in bombs and reactors. According to Einstein's equation, matter and energy are directly related and matter can be converted to energy.
Mass is a measure of the amount of matter in an object and does not change in different environments, while weight is the force of gravitational attraction on an object which does change depending on location. Weight is calculated as mass times the acceleration of gravity (w=mg), where mass is measured in kilograms and weight in newtons. On the moon, an object's mass would remain the same but its weight would be about 1/6 of what it is on Earth due to the moon's lower gravity.
1. Newton's laws of motion describe the relationship between an object and the forces acting upon it. Newton's three laws are: (1) an object at rest stays at rest and an object in motion stays in motion unless acted upon by an unbalanced force, (2) the acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, and (3) for every action, there is an equal and opposite reaction.
2. Free-body diagrams are used to represent the forces acting on an object using vectors. They help visualize and solve problems related to Newton's laws of motion.
3. Newton's laws of motion and concepts like inertia, acceleration, and friction
Light can be described as both a wave and a particle. As a wave, it travels at 300 million meters per second and is characterized by its wavelength and frequency. The different wavelengths of light make up the electromagnetic spectrum, from radio waves to gamma rays. As the frequency increases, so does the energy of the electromagnetic waves. Light also behaves as particles called photons, which are emitted or absorbed in specific wavelengths by electrons in atoms. This allows spectroscopy to be used to determine the composition of different objects by their emission or absorption spectra.
- Newton united physics and astronomy through his laws of motion and law of gravitation.
- Henrietta Swann Leavitt discovered the relationship between the variable period of stars and their absolute brightness, enabling the determination of distances in the universe.
- Edwin Hubble observed Cepheid variables in the Andromeda Nebula, proving that it was actually another galaxy, demonstrating that the universe is larger than previously believed.
Tycho Brahe made extensive and accurate astronomical observations over many years, amassing a large collection of data on planetary positions and movements. Johannes Kepler used Brahe's data to formulate his Three Laws of Planetary Motion, providing the first mathematically-based model of the solar system. Galileo used the newly invented telescope to make observations of the moon, planets, and stars that supported Copernicus' heliocentric theory and contradicted Aristotle's geocentric model, leading to conflict with the Church. Isaac Newton subsequently developed his laws of motion and universal law of gravitation, providing a unified framework for understanding motion and gravity in the heavens and on Earth.
Nicolaus Copernicus (1473-1543) published his heliocentric theory in 1543, just before his death. He realized that placing the Sun at the center of the universe with planets revolving around it made calculations and predictions much easier. This contradicted the geocentric Ptolemaic system that had been accepted for over 1400 years. Though his system was only slightly less complicated, it marked the beginning of replacing the Earth-centered view of the universe with one centered on the Sun. The Catholic Church initially ignored Copernicus' theory but eventually banned his book in 1616 as his ideas threatened established authority.
A phase diagram shows the conditions needed for different phases of matter to exist in equilibrium. It indicates that applying enough pressure to ice will cause it to melt into liquid water, as seen by the red line. The triple point of a substance is the unique temperature and pressure where its solid, liquid, and gas phases coexist. For water, this is 0.01°C and 0.006 atm.
1. The document discusses different forms of energy including mechanical, heat, chemical, radiant, electrical, sound, and nuclear energy.
2. It explains that energy from the sun is transferred through a food chain from plants to animals and is measured in calories. Stored energy from the sun can be found in fossil fuels.
3. Potential energy is stored energy due to position, while kinetic energy is the energy of motion. The law of conservation of energy states that energy cannot be created or destroyed, just converted from one form to another.
The document discusses the gas laws of Boyle's law, Charles' law, and Gay-Lussac's law. Boyle's law states that the pressure and volume of a gas are inversely proportional at constant temperature. Charles' law describes the direct proportionality of volume and temperature at constant pressure. Gay-Lussac's law found the direct relationship between pressure and temperature when volume is kept constant. The document also defines ideal gases as having no particle volume or intermolecular forces, while real gases do have particle volume and intermolecular attractive forces.
Kinetic Molecular Theory describes the behavior of gases in terms of particles in motion. It makes several assumptions about the size, motion, and energy of gas particles. Specifically, it assumes that gas particles are small, move randomly in straight lines until colliding elastically, and have a distribution of kinetic energies determined by their masses and velocities. This theory explains the low density, compressibility, and diffusion of gases as well as how temperature and pressure arise from the motion and collisions of gas particles.
The document summarizes key information about stars and stellar evolution:
- Proxima Centauri is the nearest star to our sun at about 270 km away, while the next closest stars are much farther.
- A star's apparent brightness depends on both its luminosity and distance from Earth. Luminosity is measured by absolute brightness or total power radiated.
- The Hertzsprung-Russell diagram plots stars' temperatures and luminosities and helped show stages of stellar evolution.
- Stars evolve through stages as giants, dwarfs, white and brown dwarfs, neutron stars, pulsars, planetary and diffuse nebulae as their cores fuse hydrogen and heavier elements.
This document provides an introduction to acids, bases and salts. It discusses key concepts including:
1) Acids have a sour taste and feel, bases have a bitter taste and slippery feel. Acids react vigorously with metals while bases don't.
2) When acids and bases are mixed, a neutralization reaction occurs producing water and a salt.
3) Arrhenius defined acids as substances that release H+ ions in water and bases as those that release OH- ions. Bronsted-Lowry expanded this to include acids as proton donors and bases as proton acceptors.
4) The pH scale is used to measure acidity/basicity, with acids having a pH <7 and bases
The document summarizes key information about the Sun, including its interior structure, energy production through nuclear fusion, and atmospheric layers. The Sun's core produces energy through proton-proton fusion, with a small amount of mass being converted to energy. Sunspots occur in 11-year cycles and are associated with magnetic fields, while solar flares and coronal mass ejections can emit large amounts of energy and eject plasma into space.
A solution is a homogeneous mixture composed of a solute dissolved in a solvent. A solution is formed through solvation, where solvent particles surround solute particles and pull them away from each other. The solubility of a substance depends on factors like temperature, pressure, and the properties of the solute and solvent. Increasing temperature, pressure, surface area, or agitation can increase solubility and the rate of solvation. Concentration refers to the ratio of solute to solvent and affects properties like reaction rates.
Saturn has a mass of 5.7 x 10^26 kg and is less dense than water. It has a prominent ring system composed of icy particles ranging in size from dust grains to boulders. The rings have gaps and fine structure caused by orbital resonances with Saturn's many moons. Titan is Saturn's largest moon, with a thick nitrogen-rich atmosphere that obscures its surface from view.
Uranus and Neptune are cold, gaseous planets discovered in the last 350 years using telescopes and mathematics. They have similar physical properties but Neptune shows more surface features. Uranus's unique tilted axis causes extreme seasons, while Neptune has unexplained internal heat. Both planets have moon systems, with Triton in a rare retrograde orbit around Neptune. Faint rings have also been detected circling Uranus and Neptune.
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
-------------------------------------------------------------------------------
Find out more about ISO training and certification services
Training: ISO/IEC 27001 Information Security Management System - EN | PECB
ISO/IEC 42001 Artificial Intelligence Management System - EN | PECB
General Data Protection Regulation (GDPR) - Training Courses - EN | PECB
Webinars: https://pecb.com/webinars
Article: https://pecb.com/article
-------------------------------------------------------------------------------
For more information about PECB:
Website: https://pecb.com/
LinkedIn: https://www.linkedin.com/company/pecb/
Facebook: https://www.facebook.com/PECBInternational/
Slideshare: http://www.slideshare.net/PECBCERTIFICATION
Communicating effectively and consistently with students can help them feel at ease during their learning experience and provide the instructor with a communication trail to track the course's progress. This workshop will take you through constructing an engaging course container to facilitate effective communication.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
8. C-type asteroid Mathilde The NEAR spacecraft visited the C-type asteroid Mathilde , on its way to its main target, Eros. Mathilde, like many other asteroids, has a very low density , and is probably not solid.
9. S-type Asteroids Gaspra and Ida Two small S-type asteroids, Gaspra and Ida , were visited by the Galileo probe. Gaspra (left) is in false color; it is really gray. Note that Ida (right) has a small moon, Dactyl :
13. Apollo Asteroids Some asteroids have orbits so eccentric that they cross Earth’s orbit. They are called Apollo asteroids, and raise the concern of a possible collision. 2600 such asteroids have been discovered so far, of which about 600 have been designated as potentially hazardous, due to their size.
15. Trojan Asteroids Some asteroids, called Trojan asteroids , orbit at the L 4 and L 5 Lagrangian points of Jupiter’s orbit: Lagrangian points – places where the gravity of the Sun and a planet balance
25. Meteor Showers 2011 Just past full night of December 13 Geminids Rises around midnight night of November 17 Leonids Rises after midnight night of October 21 Orionids Sets around midnight night of October 8 Draconids Full night of August 13 Perseids Sets in early evening night of May 5 Eta Aquarids Rises after midnight night of April 21 Lyrids New night of January 3 Quadrantids Moon Date of Peak Name
26. Impact Craters on Earth bosumtwi crater, ghana gosses bluff, australia vredefort crater, johannesburg, south africa
27. Impact Craters on Earth Nordlingen, Germany Odessa, Texas Middlesboro, KY
31. Comet Structure Comets have a very small nucleus , a coma of gas and dust that is the most visible part and can be very large, a hydrogen envelope , a dust tail , and an ion tail .
32. Comets The comet’s tail always points away from the sun, due to the solar wind . The ion tail is straighter than the dust tail.
34. Comets Comets have very eccentric orbits. Long-period comets have periods of hundreds of thousands, or even millions, of years. Short-period comets are less common, and have periods of less than 200 years.
35. Comets Halley’s comet is one of the most famous; it has a period of 76 years and has been observed since antiquity. Its most recent visit, in 1986, was not spectacular. Left: The comet in 1910, as seen with the naked eye. Right: the comet in 1986, seen through a telescope.
36. Comets Halley’s comet has a shorter period than most comets, but its orbit is not in the plane of the solar system, probably due to an encounter with a larger object.
38. Comets Typical cometary mass: 10 12 to 10 16 kg Each trip close to the Sun removes some material; Halley’s comet, for example, is expected to last about another 40,000 years. Sometimes a comet’s nucleus can disintegrate violently, as comet LINEAR did:
40. Comets No objects have been observed in the Oort cloud – it is simply too far away. However, some Kuiper belt objects (KBOs) have been observed – over 1000 so far.
Only within the past couple of decades have scientists taken seriously the idea that life on Earth has been disrupted over the course of billions of years by asteroid and comet impacts. We now have a much better appreciation for Earth's presence in an occasionally hostile environment, and for Earth's fragility in the face of external cosmic dangers. Here, the 5-km-diameter nucleus of comet Wild2 was imaged in the year 2004 as part of the Stardust mission designed to fly though a comet's tail--and ultimately to return samples of the tail to Earth. (JPL)
The asteroid belt, along with the orbits of Earth, Mars, and Jupiter (not drawn to scale). The main belt, the Trojan asteroids, and some Apollo (Earth-crossing) and Amor (Mars-crossing) orbits are shown. (We will learn more about these classes of asteroids later in the chapter.)
NEAR was launched on 17 February 1996 The aim of the NEAR mission was to: 1. Determine the physical and geological properties of a near-Earth asteroid. Eros was the target asteroid. 2. To further our knowledge on the nature and origin of the many asteroids, meteorites and comets close to Earth's orbit. 3. Further our understanding of how and under what conditions the planets formed and evolved. Near Shoemaker achieved all of its science goals during the year in orbit and conducted the first long-term close-up study of an asteroid. An additional bonus was despite being designed as an orbiter, it achieved the unbelievable by landing on asteroid Eros.
The C-type asteroid Mathilde, imaged by the NEAR spacecraft en route to the near-Earth asteroid Eros. Mathilde measures some 60 x 50 km and rotates every 17.5 days. The largest craters visible in this image are about 20 km across--much larger than the craters seen on either Gaspra or Ida. The cause may be the asteroid's low density (approximately ) and rather soft composition. (NASA)
The S-type asteroid Gaspra, as seen from a distance of 1600 km by the space probe Galileo on its way to Jupiter. (b) The S-type asteroid Ida, photographed by Galileo from a distance of 3400 km. (Ida's moon, Dactyl, is visible at the right of the photo.) The resolution in these photographs is about 100 m. True-color images showed the surfaces of both bodies to be a fairly uniform shade of gray. Sensors on board the spacecraft indicated that the amount of infrared radiation absorbed by these surfaces varies from place to place, probably because of variations in the thickness of the dust layer blanketing them. (NASA)
The NEAR-Shoemaker spacecraft entered orbit around asteroid Eros in February 2000, making a series of orbital corrections (engine burns) during April to bring it closer and closer to the surface before landing on the asteroid in February 2001. (b) A mosaic of detailed images showing the entire asteroid, which has a very odd shape, 34 x 11 x 11 km. Craters of all sizes, ranging from 50 m (the resolution of the image) to 5 km, pit Eros's surface. The inset shows a close-up image of a &quot;young&quot; section of the surface, where loose material from recent impacts has apparently filled in and erased all trace of older craters. (JHU/NASA)
The asteroid Icarus has an orbit that passes within 0.2 A.U. of the Sun, well within Earth's orbit. Icarus occasionally comes close to Earth, making it one of the best-studied asteroids in the solar system. Its motion relative to the stars makes it appear as a streak (marked) in this long-exposure photograph. (Palomar/Caltech)
The Tunguska event of 1908 leveled trees over a vast area. Although the impact of the blast was tremendous and its sound audible for hundreds of kilometers, the Siberian site is so remote that little was known about the event until scientific expeditions arrived to study it many years later. (Sovfoto/Eastfoto)
A bright streak called a meteor is produced when a fragment of interplanetary debris plunges into the atmosphere, heating the air to incandescence. Distant stars and the northern lights provide a stunning background for a bright meteor trail. (b) These meteors (and a red smoke trail) streak across the sky during the height of the Leonid meteor storm of November 2001. (P. Parviainen; J. Lodriguss)
A meteoroid swarm associated with a given comet intersects Earth's orbit at specific locations, giving rise to meteor showers at certain fixed times of the year. A portion of the comet breaks up near perihelion, at the point marked 1. The fragments continue along the comet's orbit, gradually spreading (points 2 and 3). The rate at which the debris disperses around the orbit is actually much slower than depicted here--it takes many orbits for the material to spread out as shown, but eventually the fragments extend all around the orbit, more or less uniformly. If the orbit happens to intersect Earth's, a meteor shower is seen each time Earth passes through the intersection (point 4).
This photograph, taken from orbit by the U.S. Skylab space station, clearly shows the ancient impact basin that forms Quebec's Manicouagan Reservoir. A large meteorite landed there about 200 million years ago. The central floor of the crater rebounded after the impact, forming an elevated central peak. The lake, 70 km in diameter, now fills the resulting ring-shaped depression. (NASA)
The world's second largest meteorite, the Ahnighito, on display at the American Museum of Natural History in New York, serves as a jungle gym for curious children. This 34-ton rock is so heavy that the Museum floor had to be specially reinforced to support its weight. The Willamette Meteorite on display at the American Museum of Natural History in New York City .
A stony (silicate) meteorite often has a dark fusion crust, created when the surface of the incoming meteoroid is melted by the tremendous heat generated during its passage through the atmosphere. (b) Iron meteorites, much rarer than stony ones, usually contain some nickel as well. Most show characteristic crystalline patterns when their surfaces are cut, polished, and etched with weak acid. (Science Graphics)
Diagram of a typical comet, showing the nucleus, coma, hydrogen envelope, and tail. The tail is not a sudden short-lived streak across the sky, as in the case of meteors or fireworks. Instead, it travels through space along with the rest of the comet (as long as the comet is sufficiently close to the Sun for the tail to exist). (b) Halley's comet in 1986, about one month before it rounded the Sun at perihelion. (NOAO)
A comet with a primarily ion tail. Called comet Giacobini-Zinner and seen here in 1959, its coma measured 70,000 km across; its tail was well over 500,000 km long. (b) Photograph of a comet having both an ion tail (dark blue) and a dust tail (white blue), showing the gentle curvature and inherent fuzziness of the dust. (See also Discovery 14-3.) This is comet Hale-Bopp in 1997. At the comet's closest approach to the Sun, its tail stretched nearly 40° across the sky. (US Naval Observatory; Aaron Horowitz/Corbis)
As it approaches the Sun, a comet develops an ion tail, which is always directed away from the Sun. Closer in, a curved dust tail, also directed generally away from the Sun, may appear. Notice that although the ion tail always points directly away from the Sun on both the inbound and the outgoing portions of the orbit, the dust tail has a marked curvature, always tending to &quot;lag behind&quot; the ion tail. (Cf. with photo of a real comet, Figure 4.10.)
Halley's comet has a smaller orbital path and a shorter period than most comets, but its orbital orientation is not typical of a short-period comet. Sometime in the past, the comet must have encountered a jovian planet (probably Jupiter itself), which threw it into a tighter orbit that extends not to the Oort cloud, but merely a little beyond Neptune. Edmund Halley applied Newton's law of gravity to predict this comet's return.
The Giotto spacecraft resolved the nucleus of Halley's comet, showing it to be very dark, although heavy dust in the area obscured any surface features. The resolution here is about 50 m--half the length of a football field. At the time this image was made, in March 1986, the comet was within days of perihelion, and the Sun was toward the right. The brightest areas are jets of evaporated gas and dust spewing from the comet's nucleus. (b) A diagram of Halley's nucleus, showing its size, shape, jets, and other physical and chemical properties. (ESA/Max Planck Institute)
Diagram of the Oort cloud, showing a few cometary orbits. Most Oort-cloud comets never come close to the Sun. Of the orbits shown, only the most elongated ellipse represents a comet that will actually enter the solar system (which, on the scale of this drawing, is much smaller than the dot at the center of the figure) and possibly become visible from Earth. (See also Figure 14.8.) (b) The Kuiper belt, the source of short-period comets, whose orbits tend to hug the plane of the ecliptic.
NASA's Stardust spacecraft captured this image (a) of comet Wild-2 in January 2004, just before the craft passed through the comet's coma. Onboard is a detector made of a foamlike gel that is 99.8% air, yet is strong enough to stop and store cometary dust particles for study upon return of the craft to Earth in 2006. (NASA)