Neil deGrasse Tyson Explains The Equivalence Principle

Does being in space mean there is no gravity? Neil deGrasse Tyson and comedian Chuck Nice explore gravity, acceleration, and Einstein’s equivalence principle. Are astronauts always floating when they’re in space?

What does it mean to escape Earth's gravitational pull? Find out what 0 G really is as we explore the concept of weightlessness. What is a translunar injection? We discuss Lagrange points, The Expanse, Ad Astra, and transitioning between objects’ gravitational pulls. Can a person on a rocket tell between 1G of gravity and 1G of acceleration? Plus, is microgravity actually a misnomer?

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About StarTalk:
Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up!

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00:00 - What does it mean to be weightless?
04:48 - Acceleration v. Gravity
07:00 - Floating in Space
09:30 - Testing The Equivalence Principle
13:33 - “Micro Gravity” & Escaping Earth’s Pull
15:10 - More Equivalence Principle

[StarTalk]

See if you can get the equivalence principle experiment to work at home. What happens?

[Hemzees]

I love how science just makes these two happy. Chuck is especially brilliant but then most comedians actually are.

[jeffs]

Thank you for finally mentioning The Expanse. It's such an amazing show that actually got a lot of the science correct. Obviously some things were embellished for drama and artistic reasons, but many things were spot on. Especially their ship designs in order to generate artificial gravity when the engines are on. Half way to their destination, the ship would flip so the rockets were then slowing them down while still generating gravity. Good on Chuck for mentioning that at the end!
They should definitely do an explainer about the show and all its science. First, though, Neil needs to watch all the seasons!!
Beltalowda!

[Jager-ervc]

I love Chuck for his comedy and the fact that he is WAY smarter then he lets on.

[PerfectChaos]

I'm glad they gave another shout out to The Expanse. An amazing story, and even better for science lovers. I've seen all 6 seasons in continuum 5 times now and also read all 9 books, and planning to re-read them soon.

[georgedeedsnotwords]

I wish I could have gotten teachers like them back in school . The passion and fun, I might have even liked being there and learning .

[ethtfxk]

You guys always manage to put a smile on my face even when times are tough. And I learn something too. Thanks for that.👍

[TamTran-vwzm]

Thanks, guys, for letting me relive my college physics class (looong time ago). I love your shows, and the pure joy of learning you show, and then give to me!

[sherrynight]

We should make StarTalk mandatory in all schools, teaching curriculum, and in the education system! 💛✨

[martinntuwa]

I love that The Expanse is recognized. It's the best space novellas I've ever seen and read.

[zero]

Just a fun fact for the Expanse.

Most of the characters you see are from the belt where they have very low gravity. They use earth’s gravity as a form of torture on these people in a scene (the weight of their body harming itself after NEVER experiencing that much gravity).

This means the acceleration and the deceleration they use (the main characters who are largely from lower gravity places) is a much lower rate than what would be 1G for us.

Which would also mean earth’s fleet can accelerate and decelerate with more force shortening their travel times (assuming they can afford the additional fuel).

[dylanroberts]

I can't stop the video until I hear Neil say, "keep looking up". ❤😊

[thewinddb]

Neil gets so amped up talking about physics. I enjoy that.

[bas]

Big hope that _The Expanse_ gets more seasons and finish the book.
It's the most realistic space series ever.

[byronwatkins]

"g" is acceleration. More specifically, "g" is acceleration due to explicit force(s). A car in a sharp turn exerts an explicit force on the occupants. A rocket after liftoff exerts an explicit force to lift astronauts into space. Gravity is everywhere -- it is called "Netwon's universal law of gravitation" for good reason. But, if other explicit forces are absent, then the resulting "free fall" (due to gravitational forces only) is perceived identically to an absence of forces.

However, the gravitational force has spherical symmetry. Each mass creates spherical shells around itself wherein all other masses get accelerated toward that mass. These spherical shells are different from a rocket engine's acceleration in one small respect: these spherical shells result in "tidal forces" -- closer objects have higher acceleration and the acceleration vectors are not parallel. In fact, these tidal forces (and small orbit corrections) are what NASA calls "microgravity."

"If you accelerate at 1 g for ten months" -- in whose frame of reference? It is not possible for mass to reach the speed of light. Viewed from earth, the ship would become more and more sluggish. At first, only very precise measurements would note the decreased acceleration. But above 0.9 c, the observed acceleration gets closer and closer to zero despite the occupants of the ship 'feeling' the same 1 g acceleration as from the beginning. Contrarily, if you tried to accelerate the ship so that viewers on earth observed a constant 1 g acceleration, then the occupants of the ship would experience higher and higher "upward" force. Eventually, this force would crush them and the ship.

[LocalFiveGuy]

I am a professional Elevator Mechanic. And, I feel like Neil Degrasse Tyson should know that the Elevator is the safest form of public transportation. Elevators have Safety devices all over the place. 😊If an elevator falls, it doesn't fall far before the safeties grab the rails.

[juancuelloespinosa]

6:35 if you wait enough time, you'll know whether you're on a rocket accelerating at 1g, or on a stationary rocket on earth.

at some point, you'll have accelerated to lightspeed, at which point you'll stop accelerating, and become weightless again (and reach the end of time since relative to you, the time of everything else stopped) whereas on earth, you'll continue to feel 1g

[riftvideos]

6:45ish I thought we used G as a term express equivalency to earth gravity for the difference in inertia in relation to two objects. ie in a fighter jet, you experience at 4g your 150lb body as if your 600lb, but you aren't being pulled toward the plane's mass. the plane is just adding to your inertia in a particular direction. if the plane had a gravitational effect on you then in a negative 4g maneuver the same person would have an outsized pull of the plane toward your mass. your body is not pulling that plane toward it, the plane is increasing the difference in inertia as the heavy plane radically alters your inertial vector dragging you along.

[TorQueMoD]

This video and your Achieving Orbit video are literally mind-blowing! Love this channel! Thanks Neil and Chuck!

[su_shadow]

I love Mr. Tyson's enthusiasm, it makes learning fun. Teachers, take note.