You know that moment on a roller coaster
when you're going over the top of a hill,
and right before you throw up, you
feel like you're hovering above your seat for a second.
What would it feel like if that moment could
last just a little bit longer?
Probably something like this.
Who does that?
It looks so awesome.
EMILY CALANDRELLI: My name's Emily Calandrelli.
And I'm a host and co-producer of Exploration Outer
Space on Fox.
Besides being a super awesome intelligent woman,
Emily has gotten the chance to go up in a plane simulating
weightlessness.
Twice.
No one's that lucky.
These planes fly and dive in such a way
that you feel like there's almost no gravity
acting on you.
It feels like you're floating in space.
Some people ask me if I've literally been to space?
See.
It's pretty funny.
But maybe it's not actually that far off.
If you consider the fundamental physics behind these two
phenomena, it's a reasonable question.
But then, I explain like, no, obviously,
I did not because going to space is really hard and dangerous.
And I'm not even sure that I would be able to go to space.
OK, besides the impracticality of getting to space,
you know, like needing a rocket launch and years
of vetting and training and all, you can't really
tell the difference between diving in the 0G plane,
or the "Vomit Comet," and actually being out in space.
Well, I guess you could just look out the window.
The nose of the plane is pointing downward
at about 45 degrees.
So you can actually tell that you're
diving toward the ground when you look out the window.
So there's that.
But in a closed box with no windows,
I bet you couldn't tell the difference
between whether you're falling to Earth
or whether you're floating out in space.
That's not really a fair bet though,
because there's no experiment you could do to tell.
This is one of the strange predictions
of general relativity called the Equivalence Principle.
You can't tell the difference between free falling
in a gravitational field, like falling to Earth,
and floating out in space away from any gravitational poles.
In fact, the "Vomit Comet" takes advantage
of the Equivalence Principle.
Here's how.
When you throw a ball up in the air with some sideways motion,
it falls back down in this shape.
You've probably heard it called a parabola.
The pull of gravity makes the ball go faster and faster.
It makes the ball accelerate.
Now, if I threw you up with the ball, ignoring air resistance,
you would fall in the same path despite your difference
in mass.
So to you, it would look like the ball were just
floating next to you.
That's the idea behind the "Vomit Comet."
The Zero G plane flies in the path
that an object in free fall would follow.
It's the same parabola.
So now, replace that ball with a plane,
and you're both moving together.
That is the path the plane follows during your segments
of weightlessness.
And that's what makes you feel like you're floating.
OK, so there's no experiment you can
do to tell the difference between this and this.
But it still seems strange to me that you're
falling, though you feel like you're floating.
How can that be?
What you feel when you're in the aircraft
is simply weightless.
You are floating in the aircraft.
And so to you, you feel like you're in space.
DIANNA COWERN: Can you explain to someone who has never
felt, like, there in space?
Because you're like, you feel you're in space.
But you know--
Like all those times you've been in space.
It feels like that.
DIANNA COWERN: All those times I've been in space.
Another like analogy is when you're underwater
and you feel buoyance, that's a little bit
of a similar feeling.
You're not going up.
You're not going down.
You really have nothing pushing against you.
Pause, this is a really important point.
Much of the sensation of floating
comes from not having a localized force acting on you.
Think about when you're sitting or you're standing.
When you're sitting down, you feel the pressure
of the chair on just your butt.
When you're floating, nothing needs to hold you up like that.
So there's no localized pressure.
You know those memory foam mattresses,
they say you feel like you're floating on a cloud.
That's because they're actually spreading the force out all
over your body to make you feel more like you're floating.
So even though you're falling in a plane--
If you don't look outside, you don't
know that you're diving towards the ground.
You don't feel that.
What you feel when you're in the aircraft is simply weightless.
Now, how is this different from skydiving?
Well, that's where air resistance comes in.
When you jump out of a plane, initially you're
falling pretty close to the rate of free fall.
But at some point, you reach terminal velocity.
This is where a lot of us get confused
because you're still falling, but you're not free
falling anymore.
The force of air resistance balances the force of gravity.
So you don't stop but you keep going at the same speed.
And if you've ever skydived, you can definitely
feel that force of air resistance on you.
Now, as awesome as the "Vomit Comet" is,
the feeling eventually takes its toll.
The most common question is did I get sick.
Because it's nicknamed the "Vomit Comet" for a reason.
And it always sucks to answer that question.
Because I want to be, like, no, I did not.
But I did.
[LAUGHTER]
The "Vomit Comet" does those parabolas over and over.
You eventually get 30 of them.
I imagine at some point, you probably
just want to get off that ride.
But it still looks like so much fun.
If you want to know more about the "Vomit Comet" experience,
keep watching for more stories from Emily.
Thank you so much to Emily for joining me at MIT.
And check out her new show "Exploration: Outer Space"
on Fox in the Fall.
This is one of the first science shows hosted by a woman.
Pretty awesome.
Thanks for watching.