Crater counting dating

This can then be extrapolated to other locations in the solar system.

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These larger chunks of material are ejected outwards from the forming crater, and they may end up forming their own craters. Secondary craters are different from primary craters in the way they look because of their formation history — mainly they are much smaller and they are also shallower.

This is both because the ejected material that formed them was much smaller than the original impactor and because the velocity of the debris is much less than the original impactor, so there is significantly less energy to form the secondary crater.

Impact craters are ubiquitous throughout the solar system – every single solid body has craters on its surface except for the moon Io (because its surface is so young due to the incredible amounts of vulcanism).

Impact craters form when an impactor – like an asteroid or comet – hits the target surface of a planet or moon.

The impact occurs at high speed, and the final crater depth, diameter, and shape are effectively determined by the surface gravity, the mass of the impactor, and the velocity of the impactor.

Almost all impact craters are circles; only impacts at very low angles (less than 10°) will form elliptical craters.

Or that the youngest stretches of terrain on our moon’s surface dates back to about 3 billion years ago?

The answer is one of the basic tools of comparative planetology: Impact craters.

The point of this background it that crater age dating has been used for over 50 years, and it rests on very solid theoretical, experimental, and observational grounds. Those same authors, Alfred Mc Ewen and Edward Bierhaus, who are not mentioned in that quote wrote a paper in 2006, “The Importance of Secondary Cratering to Age Constraints on Planetary Surfaces,” in the .

However, you wouldn’t think that given the ICR article, “Crisis in Crater Count Dating:” “New thinking about ‘secondary craters’ has thrown this whole foundation of comparative planetary dating into disarray.” The article continues with misleading statements: “One writer in estimated that a single large impact on Mars could generate 10,000,000 secondaries, and that 95% of the small craters on Europa could be from fallback debris.” You are clearly expected to infer from this that almost all craters (95%) on surfaces are secondaries by simply connecting those two phrases together. I highly recommend reading it if you are interested in this subject, and it is written at a non-technical level.

If an impactor were to hit a target at a rate of 1 per year, then a surface that’s 1,000,000 years old should have 1,000,000 craters.