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Transcript
Impact Craters
Leave an Impression…
Craters are everywhere!
Andy Saulietis
LPL / UA
The Moon
Apollo 17
NASA
Mercury
Asteroids
NASA
NASA/GSFC
Mars
NASA
NASA
Meteor Crater, AZ
USGS
Geoffrey Notkin
Even Earth…
So what causes craters?
•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
NASA
Asteroids and Comets!
When these objects collide with another body,
like the Earth, the result is a crater.
•Size: 150 Feet Across1
•Composition: NickelIron1
Wright, S.P
•Speed: 28,600 MPH1
•Age: 50,000 years old1
•Energy: 2.5 Megatons1
Meteor Crater, AZ
1Barringer
Meteor Crater Site
http://www.barringercrater.com/
Shoemaker-Levy 9
NASA/GSFC
Why do some planets have more craters
than others?
•Atmosphere
•Oceans
•Plate Tectonics
•Location
NASA/GSFC
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