We use to do most of our exploring of space. We can send , but they are very expensive. If they go wrong, then that's just tough.

Telescopes on the ground have problems due to light pollution, and haze. If it's a night, astronomers may miss something important. So they can build their telescopes on high , or take them up in .

Space telescopes the Earth. They don't have problems with atmospheric distortion and very clear can be seen.

Some objects in space give out different radiations other than light. For example neutron stars and black give out rays.