joannalannister
beautifulmars:

Fresh Small Rayed Crater: “Fresh” is a relative term, because this impact could have occurred millennia ago, but what helps determine a young from an older crater is looking at the rim: if it’s really degraded, it’s very old. But this one’s rim doesn’t look that eroded, and in addition, you can still see the ejecta pattern, which is material excavated from the impact. It’s darker than the surrounding plain, which is another indicator the impact is “fresh.” uahirise.org/ESP_029051_1660

beautifulmars:

Fresh Small Rayed Crater: “Fresh” is a relative term, because this impact could have occurred millennia ago, but what helps determine a young from an older crater is looking at the rim: if it’s really degraded, it’s very old. But this one’s rim doesn’t look that eroded, and in addition, you can still see the ejecta pattern, which is material excavated from the impact. It’s darker than the surrounding plain, which is another indicator the impact is “fresh.” uahirise.org/ESP_029051_1660