Pete Ross

So if we really did think that it had a chance of being an alien spacecraft, astronomers would be jumping for joy.

It is one of the biggest questions at the minute facing astronomy.

Are we alone?

But unfortunately, this three-eye atlas is not going to be the thing that answers that question.

It is absolutely a comet, just an alien one.

It is very, very, very old, isn't it?

Yes, we believe that it could be 7 billion years old, even older.

We think it comes from a place in our galaxy that we call the thick disk.

So if you imagine our spiral galaxy is flat and thin, like two fried eggs back to back.

Well, you put those fried eggs in a burger bun and it's kind of light and fluffy.

That burger bun is what we call the thick disk and it's where we find old stars in our galaxy.

And based on its trajectory and its great speed, that's where we think it's come from.

So older than our solar system.

One more question.

It's definitely not Santa, is it?

It's definitely not Santa.

It's been travelling far too fast for Santa.

I mean, Rudolph already has to do an awful lot of work to get around the world.

And in order to kind of have the speeds that it has moving through the solar system, I dread to think how many carrots he'd have to eat.

Dr Jennifer Millard talking to Alex Ritson.