Impact Craters Leave an Impression…. Andy Saulietis Craters are everywhere! The Moon LPL / UA NASA...
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Transcript of Impact Craters Leave an Impression…. Andy Saulietis Craters are everywhere! The Moon LPL / UA NASA...
Impact CratersLeave an Impression…
Andy Saulietis
Craters are everywhere!
The Moon
LPL / UA
NASA Apollo 17
Mercury
NASA/GSFC
Asteroids
NASA
NASA
Mars
NASA
Even Earth…
Meteor Crater, AZ
Geo
ffre
y N
otki
n
USG
S
So what causes craters?
Asteroids and Comets!
NASA
•Left over building blocks of the solar system (~5 billion years old)
•Vary in size, from a few feet to a few miles
•Millions of potential meteors in our solar system alone
•Travel in excess of 20,000 mph
When these objects collide with another body, like the Earth, the result is a crater.
Meteor Crater, AZ
Wrig
ht, S
.P
•Size: 150 Feet Across1
•Composition: Nickel-Iron1
•Speed: 28,600 MPH1
•Age: 50,000 years old1
•Energy: 2.5 Megatons1
1Barringer Meteor Crater Site
http://www.barringercrater.com/
NASA/GSFC
Shoemaker-Levy 9
Why do some planets have more craters than others?
NASA/GSFC
•Atmosphere
•Oceans
•Plate Tectonics
•Location
So why do we care?
NASA/GSFC
Extinction
Extinction
•Estimated that there have been at least 5 mass-extinctions in Earth’s history1
•Up to 90% of all species killed off2
•At least one is believed to have been caused by a meteorite1
•65 Million Years ago, Yucatan Penninsula2
•>100 Miles across2
•Force Greater than 1,000,000 megatons3 1 Lee Siegel, space.com
2 NASA/GSFC
3 Arnett, Bill, UA