Professor Geraint Lewis

Why is it important?

Well, it turns out there's a lot more of it than there is of the atoms of stuff that we're made of.

There's a lot more of this dark matter than there is normal matter.

So is it important?

Well, in your day-to-day, it might not be very, very important.

But for the Sun, it's very important because it's what holds the Sun in its orbit in the Milky Way galaxy is the dark matter.

So dark matter is very important for holding the universe together.

But the problem is we don't really know what it is.

We have got lots of ideas, but we've never found any in our laboratory.

So we're still looking for what is dark matter.

And that might unlock some new secrets to just the way the universe works.

It is, it is.

Unfortunately, it's just a weird way that the universe works.

So as you mentioned, if I start flying off to the nearest star, it might take 100 years for me to get there for people here on Earth, but to myself, it might only be a couple of days for that particular journey.

So you get that time dilation, as it's called.

But to me, on board that ship, it means that the distance to that star, as contracted, it feels a lot closer.

Mm-hmm.

And in fact, the faster and faster I go in the universe, the closer and closer everything feels.

I can get to things quicker than if I could imagine the clocks ticking back at home.

So I actually had a student work on this a few years ago.