eli5-how do we know for sure how big space is? and how do we know we are right about everything we know in space?
In: Planetary Science
We know how big the observable universe is because we can measure those distances. If you look at a star and measure it’s angle, then wait six months and check again, you can use the differences in the angles to calculate how far away it is. (Yes, it’s more complex than that, but ELI5.)
Anyway, we actually have no idea about anything outside the observable universe, including whether there even is anything there.
Finally, we don’t know that we’re right about anything, including space. All science can do is come up with theories that seem to match what we see. We have some pretty good theories, but so did Galileo, and Copernicus, and lots of other people. As we get better telescopes and other instruments, we find out that our theories weren’t exactly right, and we change them to match what we can see now. So we’re closer to “exactly right” than people were before, but we’ll still be changing our theories a little bit as we discover new things, probably forever.
Latest Answers