and while I was there one of the team just casually mentioned

that they have an artificial gravity laboratory.

Artificial Gravity Facility sounds like something out of science fiction,

but it's not, and there's very much a reason why

I'm keeping my head straight and forward at the moment.

This is the Artificial Gravity Facility, otherwise known as the rotating room.

So, let's do some experiments.

This is unscripted. I don't know what's going to happen now,

other than things are going very weird when I move my arms.

Okay, so it's a room that rotates.

No one has invented science fiction gravity generators yet,

but if you have a theoretical spaceship going to Mars

and you wanted to generate apparent gravity

to keep astronauts healthy, that's what you'd do.

You would spin up the ship and use centrifugal force.

And that lab is the research prototype.

How do humans deal with a very strange gravitational environment?

- The first thing that you should do is try to push yourself off the wall

and align your body with the direction of the resultant.

- Oh. Oh, okay!

[laughter]

- Now you're standing upright.

- Wow. Can I walk, or is that gonna--

- No, don't walk, it's a little dangerous.

- It is almost impossible to envision

long duration space flight without artificial gravity.

The best way to study artificial gravity on Earth

is to build a rotating environment.

We started designing it in the mid-80s.

Ideally we want to study its effects on the human body

and we want to learn also how to pre-adapt astronauts

to the force of artificial gravity.

99.9% of those will be highly dysfunctional individuals until adapted.

- They have NASA-standard sick bags for everyone, by the way.

I was required to keep one in my back pocket throughout just in case,

because if you tilt your head too fast

your inner ear has no idea what's going on and things go... wrong, very quickly.

- And now move your arm and try to go as straight as you can.

- [laughter]

Oh, I moved my head.

- You shouldn't move your head. - Do you get used to this?

- Yeah, yeah, you get used to it, yeah. You can adapt.

Move your arms and try to feel this force that is...

- Oh. That is...

Okay, just to be clear, I'm not putting this on,

as far as I'm concerned,

the signals I'm giving to my muscles are, 'move my arms forward'.

And now I'm forcing them.

But I'm pushing against a force here, you know.

- If you keep going, at some point you won't feel the force anymore.

- Oh that's weird.

- That's weird, right? - That's so weird.

- So now we are adapted.

- So if I try to do anything else, I haven't adjusted to it.

But that specific movement, my body's got used to.

- That's right. - Wow.

- One way to visualise this force

is for me to try and throw a little tennis ball at you.

I will throw it straight at you,

- Okay. - and see what happens, okay?

- Whoa!

What?

[laughter]

I'm struggling to work this out. Wh...

Because, in my head, this is a normal reference frame.

But it's clearly not. - We are rotating.

And now I'm gonna throw it over there.

- Yeah. - And hopefully

it's gonna get at you. - Okay.

- Are you ready?

- Yeah, throw it.

- Yes!

- Ah nice. - Great.

[laughter]

- Wow.

All those artefacts are from the Coriolis force.

It's not a real force acting on the ball, but it looks like one

when you're in that weird rotating environment.

Have a look at this 360° image of the lab.

Now, it's a little distorted because it's from a single camera in the middle,

but it's close enough. Here's the tricky part:

the circumference of a circle is longer the further out you go from the middle.

But because everything in that circle is rotating at the same speed,

once around every six seconds,

things on the outside have farther to travel, so they're

moving at a faster speed than things on the inside.

On the outside, we're moving pretty fast, but that camera in the middle

is just spinning on the spot.

So let's mark the sideways speed that everything

is moving at, relative to the rest of the world.

Green is fast, red is slow.

When you throw a ball across that room it keeps that

sideways speed that it had when it left your hand

as it travels into slower moving areas of the room.

Now, out at the edge, that was fine.

It was going the same speed as everything around it,

so it looked like it aimed for the centre.

But by the time it starts to get there, it's a missile,

flying outwards compared to everything around it.

Now from the outside that make sense.

After it leaves your hand, the ball

just moves in a straight line.

From the inside it looks like there's a force suddenly sending it sideways,

and that is the Coriolis force.

And it's not something your brain has evolved to deal with.

- Now, if you move your arms, you're pretty much fine.

- Oh! I...

[laughter]

- Just by moving around, you have been adapting.

- That's ridiculous. Thank you so so much.

I'm gonna throw this at you one more time, okay?

- Okay.

[laughter]

- The question that lab needs to answer is:

Can humans adapt to that over time?

And if so, how long does it take them to come back down to Earth?

Let's bring this to a stop!

Avi, can you bring us to zero?

Bring your hands down and don't move.

- I swear, the room is tilting--

- Don't move!

Oh, that's weird.

- And we're stopped, so try to swing your arms in front of you.

[laughter]

Oh, I don't like that.

- You've been adapted.

There are no unusual forces on your arms but

you feel it, right? - But they're still, yeah,

They're still doing that.

- And now you have to re-adapt.

- Thank you so, so much.

Thank you so much to everyone at the Ashton Graybiel

Spatial Orientation Lab at Brandeis University.

Pull down on the description for more about them and their work.