If the lunar maria are impact craters, why don't they have central peaks? They're as smooth as a baby's behind!
$\begingroup$
$\endgroup$
1
-
$\begingroup$ Lunar Maria itself are not impact craters. It is true that the moon has witnessed many asteroid impacts which created craters all over the surface. However, liquid magma flowed through cracks and crevices and onto the surface and levelling the surface (and thus dissolving the impact the peaks as well) and filling the crater eventually. The levelled surface is what is known today as lunar Maria. See: lovethenightsky.com/how-did-lunar-maria-form $\endgroup$– Nilay GhoshCommented Jun 28 at 1:48
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
The lunar maria are massive plains of basalt that were formed by ancient lava flows filling up the impact basins from even older meteors, back before the moon became cold enough to be geologically dead. The exact timeline of events is still under debate -- whether the meteors that created those basins were also responsible for starting the eruptions that filled them in, or if the eruptions happened later for other reasons and just filled in the local low points.
In either case, the central peaks of those craters were either melted or drowned or both, if the craters had peaks in the first place. Sometimes the central peak of an impact crater disappears due to slumping and other effects, even when lava doesn't come fill in the basin.
