Charles Hakes Fort Lewis College1 Photos. Charles Hakes Fort Lewis College2 Chapter 4, 5 Debris -...

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Photos

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Chapter 4, 5

Debris -

Asteroids and Comets

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Tutor (Shane)

Thursday 5-6 (or longer if needed) BH640

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Movie comments

Martian atmosphere Asteroid density

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Debris

• Asteroids• Mostly between Mars and Jupiter.• Silicate (rocky) predominate inner region• Carbonaceous more common as you move out

• Meteoroids - Little Asteroids• Micrometeoroids -

• Really little ones (dust)• Often follow comet paths

• Comets - Dirty Snowballs

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Chapter 4Asteroid Eros

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Asteroids (Minor Planets)

• Most are in the “Asteroid belt” between Mars (1.5 AU) and Jupiter (5.2 AU).

• Largest is Ceres (940 km in diameter).• Orbits generally more elliptical than planets• Trojan asteroids - in stable orbits 60°

ahead of and behind Jupiter.• Vesta - http://apod.nasa.gov/apod/ap110919.html

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Figure 4.4Inner Solar System

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Figure 4.6Asteroid Images

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Figure 4.7Asteroid Eros

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Asteroid Density

• How close are the Asteroids to each other?

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Asteroid Density

• How close are the Asteroids to each other?• Number of known asteroids ~100,000.• Distance from sun 2-4 A.U.

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Asteroid Density

• How close are the Asteroids to each other?• Number of known asteroids ~100,000.• Distance from sun 2-4 A.U.• Area ~ (4AU)2 - (2AU)2 = 8.5x1017 km2

• Say there are really lots more… (~1,000,000,000)

• Then each one still gets 8.5x108 km2

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Asteroid Density

• How close are the Asteroids to each other?• Number of known asteroids ~100,000.• Distance from sun 2-4 A.U.• Area ~ (4AU)2 - (2AU)2 = 8.5x1017 km2

• Say there are really lots more… (~1,000,000,000)

• Then each one still gets 8.5x108 km2 Distance = 3x104 km (~2.5x diameter of Earth)

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Asteroids (Minor Planets)

• Over 2000 Earth-crossing asteroids are known.

• Near Earth - http://apod.nasa.gov/apod/ap111001.html

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Discovery 4-1aWhat Killed the Dinosaurs?

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Figure 4.15Barringer Crater (near Winslow, AZ ~25,000 years ago)

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Figure 4.17Tunguska Debris (Siberia, 1908)

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Figure 4.16Manicouagan Reservoir (~200,000,000 years ago)

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Discovery 4-1bWhat Killed the Dinosaurs?

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Figure 4.18Meteorite Samples a) stony silicate b) iron

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This is:

A) A natural rock outcropping

B) New FLC Landscaping

C) Something else

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Comets

• Dirty snowballs

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Comets

• Nucleus • Dirty Snowballs - “dirt” accumulates on surface• Often only a few km in diameter

• Coma• Bright part around the nucleus• Could be 100,000 km in diameter

• Tail• Could be up to 1 A.U. in length!• Ion Tail - points directly away from the Sun• Dust Tail - points away from Sun, but “drags” a bit.

• Hydrogen Envelope - surrounds all, but not visible

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Figure 4.8Halley’s Comet

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Figure 4.9Comet Tails a) Giacobini-Zinner b) Hale-Bopp (1997)

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Figure 4.10Comet Trajectory

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Figure 4.11Halley’s Comet Closeup from Giotto spacecraft

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Figure 4.12Comet Reservoirs

•Oort Cloud •huge•spherical•reservoir of long period comets

•Kuiper Belt•outside the orbit of Neptune•in plane of solar system•reservoir of short period comets•e.g. Haley’s comet

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Figure 4.14Meteor Showers

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Figure 4.13Meteor Trails

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Figure 4.13Meteor Trails

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Three Minute Paper

• Write 1-3 sentences.• What was the most important thing

you learned today?• What questions do you still have

about today’s topics?