how can we believe anything??

[LostLocke]

Nope.
Everything we know about space we got by going into space.

exactly! but not us as individuals. The majority of people on this planet have never been to space - but we still believe the photos and videos we are shown to be real.

There are lots of things you can look at in space directly, which conform to what we know about them by going there.

You can shine a laser at the moon and have it reflect black to you, and use that to calculate the distance, speed, etc of the moon. Which would be absolutely impossible had we not gone to the moon and put the mirrors there in the first place.