How are craters on the Moon being dated?
Traditionally, dating craters is done by recording the number and size of superimposed craters on the ejecta — the material displaced by impact — of each crater.
Why does crater density vary on the Moon?
The density of impact craters varies from the heavily cratered southern hemisphere to very sparsely cratered regions like the polar dune fields and laminated terrain. In the 40° to 60° latitude belts, particularly, significant surface modification has occurred since the presently observed crater population formed.
What does cratering density have to do with the surface of the Moon?
The amount of cratering is usually an indication of the age of a geological surface: the more craters, the older the surface, because if the surface is young there hasn’t been time for many craters to form. Some regions of the moon exhibit near maximal cratering density, indicating that they are very old.
Why are there craters on the Moon activity?
Look at the Moon. These craters formed when rocks or comets from space smashed into the surface of the Moon. The impact was so powerful that it pulverized the ground – creating what we call regolith – and sprayed it out to form those ejecta rays.
How is crater density used in the relative dating of lunar surface features?
They are both made from fluid basaltic lavas that spread across a flat area. How is crater density used in the relative dating of surface features on the Moon? The greater the crater density, the older the feature is supposed to be. List the major stages in the development of the modern lunar surface.
How old are the craters on the Moon?
It became apparent that surfaces older than ∼4 Ga had so many impacts that new craters just obliterated old ones; 4 billion years represents an upper age limit for the method. There are interesting features in the lunar cratering record.
How are the number of craters on a planet determined?
The number of craters on a planetary surface is determined by the age of the surface and the average crater production rate. Know one of these variables and you can constrain the other.
Why are impact craters more common on the Moon than on Earth?
The terrestrial planets also are too small to exert the gravitational pull required to hold very light gases in their atmospheres. Why are impact craters more common on the Moon than on Earth, even though the Moon is a much smaller target and has a weaker gravitational field?