Should we steer comets into Mars to give it oceans?

Even if all those comets released any water, Mars doesn't have sufficient gravity to retain it. read more

First of all, we don’t have the technology to steer comets into Mars. If we steered comets into Mars, that could wipe out life that we may otherwise discover. And an ocean isn’t possible to exist on Mars now because the atmosphere isn’t thick enough and most of it is also too cold. Liquid water would just quickly vaporize or freeze. read more

It's not only unhealthy for Earth life forms and impossible to move in in the way that Earth life forms are designed to move, but also really weak for holding on to whatever atmosphere we give it, so even if we modified the DNA of every species we took with us to handle the gravity and gave the planet an atmosphere, the atmosphere would be short-lived. read more