The cloud that produces rain is the cumulonimbus cloud.
The difference would be that Mercury has a denser, warmer atmosphere and Earth has a not that dense and gassy atmosphere. The Earth's atmosphere also has a lot of layers while Mercury's doesn't. Those would be the reasons for them both being different. Hope this helped!
One of the ways to minimize a collision is to slow down: When you can't find an escape and you're definitely going to collide with something, you should slow your vehicle down as much as possible.
Hope this helps ^^
