[zcaveman]

This is for the rocket scientists and space people out there.

We have sent two land rovers (Spirit and Opportunity) to Mars and now we have sent the Phoenix Mars lander to Mars to see if there is water and other elements that would indicate that there is life on Mars.

My question is - why do we think that alien life forms need water or the elements that we need to live? We have never captured or found an alien life form so how do we know what it needs to exist?

Can someone enlighten me as to why we spend billions of dollars to see if life forms in our mode exist when we could use the money to cure the ills of the world?