23-4 Flashcards
(18 cards)
what was NASA’s DAWN?
first probe to orbit asteroid in asteroid belt, took high-res photos
what are asteroids, where are they located, and what is the largest?
rocky objects located between the orbits of Mars and Jupiter.
The largest asteroid - Ceres; most small and irregularly shaped. Some asteroids scattered through solar system, with few captured as moons.
how may the asteroid belt have formed? What are the potential risks of asteroids?
The asteroid belt may have formed due to Jupiter’s gravity preventing planet formation, or from collisions of large objects. Some asteroids have elliptical orbits that bring them near Earth, posing a collision risk.
what is a comet?
rocky metallic materials held together by frozen water, methane, carbon dioxide and ammonia; orbits long, narrow ellipses
what is a coma? how is it formed?
comet like a large, dirty snowy rock, mass of frozen ice and rock. As comet approaches sun it starts to warm up, causing water, methane, and ammonia ice to vaporize, this releases gas and dust forming fuzzy outer layer (coma)
what is the nucleus? what is the brightest part of a comet made of?
solid inner core of comet; brightest part of comet made of nucleus and coma
How does a comet’s tail form and behave?
Vaporized gases from the coma are released, creating a tail.
Radiation pressure from the Sun pushes dust particles away, forming a bright tail that always points away from the Sun.
A second tail made of ionized gases follows, pushed outward by the solar wind
What happens to a comet after many trips around the Sun?
After hundreds of trips, most frozen ice vaporizes. Small leftover particles spread out along the comet’s original orbit, becoming meteoroids.
what is the kuiper belt?
Doughnut-shaped region beyond Neptune where comets move in near-circular orbits, mostly in the same plane as the planets. Comets here have shorter orbits
Jovian planet/comet collisions/gravitational pulls can send comets in inner solar system
what is the oort cloud?
Jan Oort proposed a cloud of comets surrounds the solar system. Changes in their orbits can send comets toward the Sun. Nearby stars or space objects may affect the Oort Cloud.
what is comet halley?
Edmund Halley found the famous comet returns every 76 years. The Giotto probe showed its potato-shaped, cratered nucleus, with gas and dust gushing out to form the coma and tail.
What are meteoroids and what are the 4 ways they can come from?
pieces of rock moving through space. They can be:
1. Remains of expired comet nucleus.
2. Material from the asteroid belt.
3. Fragments from moon or Mars after asteroid impacts.
4. Interplanetary debris not swept up by planets.
What happens if a meteoroid crosses Earth’s path?
If a meteoroid crosses Earth’s path, it would enter our atmosphere.
what is a meteor?
meteoroid that burns up in Earth’s atmosphere, creates friction, heat, and light
what are “shooting stars”?
small meteoroids completely vaporized in Earth’s atmosphere;
occurs each time Earth passes through loose group of particles in path of a broken up comet, small particles of rock and dust enter atmosphere
what is a meteor shower?
when more meteors than usual are seen
what is a meteorite?
meteoroid large enough, not burnt up in Earth’s atmosphere but strike Earth. used to be the only extraterrestrial materials directly examined
what are micrometeorites?
dust that atmosphere slows down so it doesn’t burn up, will reach Earth’s surface.
Oldest known materials in the solar system - mostly of iron, others silicates
