Discussion in 'General Discussion' started by froggy, Oct 18, 2009.
why isn't the earth full of craters like all the other planets and moons?
because it is, we just have things like oceans to cover them up
Not all the other planets are full of craters. It depends how geologically active they are (or for the outer planets, whether they have a surface at all). On Earth craters erode with time. On the Moon, there's no rain. Or wind. Or anything else that can erase them. They just stay as they are pretty much forever.
if one of the smallest get hit this many times, and most of the others look the same shape why not earth?
lok at the planets
how is babby formed?
Because the Earth's surface is being repaved and resurfaced including by weather erosion, glacial action, vegetation, volcanic eruptions, inundation by oceans, even plate tectonics wipe them out over time. So they are being erased faster than collision events take place to create new ones. Still, they are more common than we realize, which has become apparent since we've been able to image Earth's surface from space.
Two craters which immediatel come to mind is the crater at Kentland, Indiana is almost 5 miles in diameter and is less than a hundred million years old.
There's a huge one at Sudbury Ontario Canada which is almost 2-billion years old, and there's the famous big one in Arizona, but there are craters in Kentucky, Iowa, Missouri, Ohio, New Jersey, Utah, Texas. Being able to get view from orbit makes these stand out more; even shadows when they are at the day/night "terminator"
An extreme example of a planetary sized body pretty much without craters is Jupiter's moon Io. Due to gravitional tides produced by its proximity to Jupiter, its surface is being re-paved by volcanic action much more quickly than new collision events produce craters. There are some, but they are very rare. Since Jupiter operates like a giant magnet to asteroids and space debris because of it's size/gravitaional field in that region of space there ought to be more on it's moons than on other planetary bodies.
Recently discovered is an entire crater field - an area peppered with more than 100 craters - covering more than 150 square miles in Argentina, called the Bajada del Diablo field. It was struck between 130,000 to 780,000 years ago. There was an aerial photo of it in the most recent issue of "The Planetary Report." Since I wasn't able to find an aerial photo image on the internet I've scanned an it as an attachment image at the bottom of this post. It is from The Planetary Report.
Covering 400 square kilometers (154 square miles), the Bajada del Diablo field is peppered with at least 100 depressions left by the collisions of meteorites or comets 130,000 to 780,000 years ago, the study found.
Click on image to enlarge
we're not talking about water trenches, it's about space rocks pounding earths surface.
When that happens froggy, you won't be alone. We will all croak!
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