Is There Gravity in Space?

In a word, "yes" - space is packed with gravity. Hank explains how Isaac Newton described how gravity works, and why even though it seems that things are floating in space, they're still effected by gravity. Every object in the universe is constantly attracting every other object in the universe.

[Raezores]

But 1 question: How would you eventually fall into that planet, if lets say you were at the one end of the observable universe, and the planet on the other side? Wouldn't that mean the expansion of space would make those 2 objects move away faster than the speed of light because space expands faster than it and it probably wille expand forever? How would you then eventually fall into that planet then?

[sdfjsdjfghssfgdsgvfs]

"Every object is constantly attracting every other object in the universe"
Suddenly I feel very attractive :D

[toonbat]

This is one of my favorite explanations ever for an orbit.

[dilllz]

Correction for you hank: If I remember correctly, Newton never actually found the gravitational constant. It was the Cavendish experiment (conducted years after Newton's death) that was able to calculate the gravitational constant. This also allowed us to know the mass of the earth.
All Newton ever determined was the product of the gravitational constant and the mass of the earth.

[aaronhuff]

Do we actually know if the force gets weaker with distance? What experiments shoe this? Thanks

[Nulono]

" There is an art, it says, or rather, a knack to flying. The knack lies in learning how to throw yourself at the ground and
miss."
-The Hitchhiker's Guide to the Galaxy

[VanOysterson]

Guy I knew on Facebook thought the moon landing was fake, and his reasoning was that he thought there was no gravity in space so they would just fly up into the sky. He thought he was being so damn clever too. 

[Smidgenism]

"Dude, no edge!" -Hank Green
"Space: wall to wall with gravity." -Also Hank Green

[UponGiantsShoulders]

I can only speak for myself, until field theory, and actually doing the maths involved and fully comprehending asymptotic behavior I did not REALLY understand. I think it remains profoundly important to stay humble, and that was why I made my user name what it is, nothing I know did I learn from my own creativity and hard work, but from the hard work of the giants whose shoulders I stand on to see as far as I do. Helping others find the path, and get up on these shoulders with me is the goal.

[trinix]

You are correct, other people have answered my question and I looked it up but yet you managed to contribute some juicy stuff. One of the things I was curious about, which got answered before is that these orbits are veeery very slightly growing or shrinking and that satellites and the space station has to slightly compensate for those "imperfections" by own manual forces.

[mechwurm]

the weirdest thing to me is that a pencil in the Andromeda Galaxy would actually produce a force on me. Granted it would be so negligible that it would be incomprehensibly tiny but it still exists

[DizzyDior]

"Every object in the universe is constantly attracting every other object in the universe." O_O Woah. Space is crazy. And

[Raattis]

Actually, the expansion of the universe could keep you from ever coming into contact with the planet.

[SuperLegoman]

The definition of velocity is
1 The speed of something in a given direction.
2 (in general use) Speed.
And gravity stops it being at a "constant velocity". If #2 happens the object will maintain a constant speed (the definition of a constant speed is the type of speed that does not change or stays constant) around the object. And you don't need to keep accelerating to stay in orbit, several simple examples are: the moon, all things orbiting the sun, the entire galaxy.

[TheRedAzuki]

It will be in Newton(As that is the universial unit for force), so if you then divide your Mass from that, you will get the acceleration(F=MA, F/M=A) towards that object. F/M1=G*M2/(r^2) Then you can use A to calculate your speed, via an integral as A is the intergral of V which is the intergral of S

[therealorberon]

I have a question. where does the horizontal velocity comes from? 

[christiancecere]

you wouldn't hit the planet because the space between you and the planet would expand faster than you would "fall."

[DScottWhitaker]

Excellent way of explaining gravity! Thanks for sharing!

[TheFounderUtopia]

Hey Hank? I'm curious as to how you would answer this question: What IS space? Beyond the mere definition, I'm talking about the actual meaning, the thing (or lack thereof) it is applied to. Assuming there were no objects with which we could create a distance-based frame of reference, how would you determine how big space is, what generates it, or even that it is there? I understand that it is an environment, and connected intrinsically to time, but as a *definition* does that not seem circular?

[pocok]

Some people think there is no gravity in space??? Seriously??