meteors, comets, asteroids

8/3/2019 Meteors, Comets, Asteroids

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Asteroids, Meteors, Comets

Solar System Debris


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Meteors Meteorthe bright

streak of light that is

produced when apiece of debris burns

in earths atmosphere

Meteoroidthe piece

of debris (usually

smaller than 1 cm)


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Meteorites Meteoroids strike earths

atmosphere going

20-160 thousand mph

Burn in atmosphere between 60 50 milesabove ground

If debris is large enoughand doesnt all burn, the

piece that strikes theground is the Meteorite

To findlook in desert orin Antarctica

Not usually very large,butoccasionally we getbigger ones.


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Why Meteor Showers OccurEarth orbits through a trail of debris

(usually left behind by comet or other parent)


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Meteor ShowersShower Name Date of Max Parent ObjectQuadrantids Jan. 3

Lyrids Apr. 22 Comet Thatcher

Eta Aquarids May 4

Delta Aquarids July 29

Perseids Aug. 12 Comet Swift-

TuttleOrionids Oct. 21 Comet Halley

Leonids Nov. 16 CometTempel-Tuttle

Geminids Dec. 13 Asteroid Phaethon


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Types of Meteorites Stony meteorites94% of all that fall to Earth(most are chondritesnamed for chondrules ofglassy silicates inside)

Iron meteorites5% of meteorites that fall to Earth(nearly pure iron and nickel)

Stony-iron meteorites1% that fall to earth

Age of meteorites is about 4.5 billion yrs. oldleft

over from solar system formation Parent bodiesasteroids


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The Possible Evolution of a Parent

Body of Meteorites


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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 acrossproduced by a meteorite that

was ~150 ft. in diameter


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So what would happen if.Impact Diameter (m) Yield (megatons) Interval (yrs. Consequences

~10 m


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Q:When did this happen?

A: about 50,000 yrs. ago

Meteor Crater (Winslow, AR)

Whens the next one? um, we dont know


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Asteroids Asteroidsmetallic, rocky bodies

without atmospheres that orbit theSun but are too small to beclassified as planets.

How many are there? We now know orbits of

50,000but we dont know themall

Most are found in asteroid beltbetween Mars and Jupiter

(2.1-3.3 AU)

Lots of space in between themits not like StarWarstheyreabout 5 million km apart


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Asteroid Locations

7000 asteroids in1997 (not to scale)

Trojan

asteroids

Trojan

asteroidsJupiter


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Do Asteroids come near Earth? Amor Asteroidspass inside Mars orbit but dont cross

Earths

Aten asteroidscross Earths path when furthest from sun Apollo asteroidsEarth crossing asteroids (largest known is

~8km in diameter)


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The Size of Near-EarthAsteroids


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What are the largest asteroids?

Ceres (now classified as a dwarf planet likePluto) is 1000 km in diameter (see image)

Pallas and Vesta are both ~500 km in

diameter


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The asteroid Toutatis has

dimensions of2.9 x 1.5 x 1.2 miles


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951 Gaspradimensions of

18.210.58.9 km


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433 Erosdimensions of

13 13 33 km


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Near Earth Asteroid Rendezvous

(NEAR) mission visited andlanded on Eros in 2000


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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, theres a concentration of

iridium worldwide from a settling

of a worldwide dust


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Comets Dirty Snowball

made of ice (frozen

water, CO2, CO,formaldehyde),dust,

rock


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The Parts of a Comet


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The Orientation of

Comet Tails

Tail always points awayfrom the sunso it can

lead the comet (like at

the right of the diagram)


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Comet Halle-Bopp in 1997

(nucleus of 40 km)


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Comet Hyakutake in 1996

(nucleus of 2 km)


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Halleys comet in 1986

(nucleus of 15 km)


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The Oort Cloud


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Stellar Perturbations


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Kuiper Belt Comets


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Comet Shoemaker-Levy 9

(impacted in 1994) 1994 string of a

comets broken apart

fragments labeled AthroughW heading

straight toward Jupiter

real time impact

witnessed during our

lifetime


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What it would have looked like

on Earth compared to Jupiter


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1. Graph radius of crater (y-axis) vs.height of drop (x-axis).

Remember to make your graphwith labels, units, and evenly

marked out intervals.

2. Graph radius of crater (y-axis) vs. mass of sphere (x-axis).

Remember to make your graphwith labels, units, and evenlymarked 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 theasteroid.What might be other factors we did not consider that mayalso affect the size of craters left behind by an asteroid? (think of atleast 2)

3. For the 2 factors that you listed above, give a hypothesis for each.How do you think these factors would affect the craters size?

4. In addition to the radii of the craters, what other qualities of thecraters could be measured or studied?

5. How do you think the angle of impact might affect the size or shapeof the crater left behind? Provide sketches in addition to words toanswer this question.

6. In scientific terms, how have comets and asteroids played a role in theevolution and development of the terrestrial planets in our solarsystem? Be specific for each planet: Mercury, Venus, Earth, Mars,

and the Moon.

meteors, comets, asteroids

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