A rock has to get off of the body where it formed, it has to travel through space, then it has to land safely on a new body, and once it get there it has to find a congenial environment. Of the three, landing is probably the easiest.

It's completely possible that there's no water involved at all and that what we're seeing are just dry flows of dust and sand. You can get massive flows of material that's completely dry and ends up having pretty much the same shape as if they were wet.

how much does it cost now for a mock space travel in the planetarium? That will b the future cost of space travel, Isnt it?

future space travel = Your bus and taxi fare here is how u get the same idea that i have. goto any nearest planetarium and see the show. at the end of it just say 2 questions. how was the space travel? HOw is the space ship?

It is looking more and more likely that this could be a problem for long-term space travel.

There is a place in Virginia looking at space travel. Some of the financial backers own large travel agencies. There is big interest in this in the corporate world.