Solar System Debris Asteroids Meteors Comets Meteors Meteorthe

Solar System Debris Asteroids, Meteors, Comets

Meteors • Meteor—the bright streak of light that is produced when a piece of debris burns in earth’s atmosphere • Meteoroid—the piece of debris (usually smaller than 1 cm)

Meteorites • Meteoroids strike earth’s atmosphere going 20 -160 thousand mph • Burn in atmosphere between 60 50 miles above ground • If debris is large enough and doesn’t all burn, the piece that strikes the ground is the Meteorite • To find…look in desert or in Antarctica • Not usually very large, but…occasionally we get bigger ones.

Why Meteor Showers Occur— Earth orbits through a trail of debris (usually left behind by comet or other parent)

Meteor Showers Shower Name Quadrantids Lyrids Eta Aquarids Date of Max Parent Object Jan. 3 Apr. 22 May 4 Comet Thatcher Delta Aquarids July 29 Perseids Aug. 12 Orionids Leonids Geminids Oct. 21 Nov. 16 Dec. 13 Comet Swift. Tuttle Comet Halley Comet. Tempel-Tuttle Asteroid Phaethon

Types of Meteorites • Stony meteorites— 94% of all that fall to Earth (most are chondrites…named for chondrules of glassy silicates inside) • Iron meteorites— 5% of meteorites that fall to Earth (nearly pure iron and nickel) • Stony-iron meteorites— 1% that fall to earth • Age of meteorites is about 4. 5 billion yrs. old…left over from solar system formation • Parent bodies…asteroids

The Possible Evolution of a Parent Body of Meteorites

What happens if a REALLY big meteorite makes it through the atmosphere and hits a planet? Meteor Crater (Winslow, AR) Crater is almost 1 mile across…produced by a meteorite that was ~150 ft. in diameter

So what would happen if…. Note: Atomic Bomb on Nagasaki energy release= only 20 kilotons H-Bomb release = ~60 Megatons

Q: When did this happen? A: about 50, 000 yrs. ago Meteor Crater (Winslow, AR) When’s the next one? …um, we don’t know…

Asteroids • Asteroids—metallic, rocky bodies without atmospheres that orbit the Sun but are too small to be classified as planets. • How many are there? • We now know orbits of 50, 000…but we don’t know them all • Most are found in asteroid belt between Mars and Jupiter (2. 1 -3. 3 AU) • Lots of space in between them… it’s not like Star Wars…they’re about 5 million km apart

Asteroid Locations 7000 asteroids in 1997 (not to scale) Trojan asteroids Jupiter

Do Asteroids come near Earth? • Amor Asteroids—pass inside Mars’ orbit but don’t cross Earth’s • Aten asteroids—cross Earth’s path when furthest from sun • Apollo asteroids—Earth crossing asteroids (largest known is ~8 km in diameter)

The Size of Near-Earth Asteroids

What are the largest asteroids? • Ceres (now classified as a dwarf planet like Pluto) is 1000 km in diameter (see image) • Pallas and Vesta are both ~500 km in diameter

The asteroid Toutatis has dimensions of 2. 9 x 1. 5 x 1. 2 miles

951 Gaspra—dimensions of 18. 2× 10. 5× 8. 9 km

433 Eros—dimensions of 13 × 33 km

Near Earth Asteroid Rendezvous (NEAR) mission visited and landed on Eros in 2000

The Chicxulub Impact Structure 100 -150 mile diameter crater off Yucatan Peninsula dating back to 65 millions years ago… So what? This is the same time as dinosaur fossils; in layers of sediment, there’s a concentration of iridium worldwide from a settling of a worldwide dust

Comets • “Dirty Snowball”— made of ice (frozen water, CO 2, CO, formaldehyde), dust, rock

The Parts of a Comet

The Orientation of Comet Tails Tail always points away from the sun…so it can lead the comet (like at the right of the diagram)

Comet Halle-Bopp in 1997 (nucleus of 40 km)

Comet Hyakutake in 1996 (nucleus of 2 km)

Halley’s comet in 1986 (nucleus of 15 km)

The Oort Cloud

Stellar Perturbations

Kuiper Belt Comets

Comet Shoemaker-Levy 9 (impacted in 1994) • 1994 string of a comets broken apart • fragments labeled A through W heading straight toward Jupiter • real time impact witnessed during our lifetime

What it would have looked like on Earth compared to Jupiter

1. Graph radius of crater (y-axis) vs. height of drop (x-axis). Remember to make your graph with labels, units, and evenly marked out intervals. 2. Graph radius of crater (y-axis) vs. mass of sphere (x-axis). Remember to make your graph with labels, units, and evenly marked out intervals. Conclusion Questions 1. Is there a trend to your graphs and your data? Explain. 2. We varied the height (and indirectly, the speed) and the mass of the asteroid. What might be other factors we did not consider that may also affect the size of craters left behind by an asteroid? (think of at least 2) 3. For the 2 factors that you listed above, give a hypothesis for each. How do you think these factors would affect the crater’s size? 4. In addition to the radii of the craters, what other qualities of the craters could be measured or studied? 5. How do you think the angle of impact might affect the size or shape of the crater left behind? Provide sketches in addition to words to answer this question. 6. In scientific terms, how have comets and asteroids played a role in the evolution and development of the terrestrial planets in our solar system? Be specific for each planet: Mercury, Venus, Earth, Mars, and the Moon.