You know what time it is. It's time for Ask a Space Man. I'm Paul Sutter. You've got questions and I've got answers. You know how the show works, but I'm going to tell you anyway,

because that's just what kind of guy I am. You go online to Twitter or Facebook, use the hashtag

Ask a Spaceman, and ask questions about space. Whatever comes to mine, I'll be happy to answer it.

You can also follow me on Twitter and Facebook. My name is Paul Matt Sutter,

Sutter like butter, but with an S. And you can also go to askaspaceman.com. There you'll find show

notes and discussion. You can ask questions there. We have one simple goal with this show.

Complete knowledge of time and space. It's going to take a while,

but we're going to do it one episode at a time. And today's question is one of my favorite kinds of

questions. It's how do we know this question? There's lots of stuff in science that's just presented as facts and ideas,

and it's important that we explain how we know things. We're just not making things up as much as we would like to do that because it would make our jobs a lot easier.

It's important to explain what goes on behind the scenes of how we've convinced ourselves

that something is happening, that something exists.

And in this case, it's about dark matter.

Not dork matter, that's something else, dark matter.

And the question is, what's up with dark matter? How do we know

that dark matter exists? And I often hear from people or read online that it's a, people say,

oh, it's a, it's a conflict between theory and observation.

I don't know who that is speaking, but I hear that a lot, that there's this conflict between what we expect to be there and was actually there, and we're just making stuff up, and

we just call it dark matter.

That couldn't be farther from the truth.

The actual situation is almost totally different it's not theory versus observation it's observation versus observation and i'll show you what you what i mean

the problem in the question of dark matter in the existence of dark matter

...