How does Gravity exist?

[Mr. Quark]

How does Gravity exist? How did matter start to have a "pull" on matter?

[YNM]

They... just did ?

[Green Baron]

Gravity is one of the four fundamental forces in physics. It exists. Fullstop.

You can ask "why is the sky blue", that is deducible, the fundamental forces aren't.

A yet-to-be-found theory of everything might one day be able to tell us more.

 

Edit: you might want to dive into General Relativity as a means to describe the effect of Gravity but that wasn't quite the question ...

Edited September 6, 2017 by Green Baron

[Snark]

7 hours ago, Mr. Quark said:

How does Gravity exist? How did matter start to have a "pull" on matter?

That's a darn good question, and one that the scientific community would really like to find out.  If you get an answer, let 'em know, okay? 

(Also, moving this to Science & Spaceflight)

 

[Mr. Quark]

6 hours ago, Snark said:

That's a darn good question, and one that the scientific community would really like to find out.  If you get an answer, let 'em know, okay? 

(Also, moving this to Science & Spaceflight)

 

So sorry for starting threads in the wrong category. It's been a while so I forgot which sections where.

[Snark]

14 minutes ago, Mr. Quark said:

So sorry for starting threads in the wrong category. It's been a while so I forgot which sections where.

No problem, happens all the time, you have plenty of company.  That's what moderators are for. 

(Well, one of the things we're for, anyway.)

[wumpus]

Punchline: "Of these four forces, there's one we don't really understand." "Is it the weak force or the strong--" "It's gravity.""
 

Presumably the known existence of the Higg's boson at least tells us a little more about gravity (I think the Higg's boson helps explain mass).  I got about to this level of the four forces (plus Maxwell's equations, but don't  ask me to use them now) so can't help you beyond this.

[p1t1o]

Im a chemist by training so for me gravity doesnt exist.

[Green Baron]

Now how does a chemist avoid gravity ?

:-)

[Steel]

59 minutes ago, wumpus said:

Presumably the known existence of the Higg's boson at least tells us a little more about gravity (I think the Higg's boson helps explain mass).  I got about to this level of the four forces (plus Maxwell's equations, but don't  ask me to use them now) so can't help you beyond this.

The discovery of the Higgs reveals pretty much nothing about gravity. It confirms Higgs' (not forgetting Anderson, Brout, Englert, Guralnik, Hagen, Kibble and 't Hooft) theory about why some particles have a small amount of intrinsic mass and that's about it (well that's not really it, but there's nothing else really worth highlighting here)

[G'th]

On 9/6/2017 at 10:15 AM, Mr. Quark said:

How does Gravity exist? How did matter start to have a "pull" on matter?

The why isn't really something we have an answer for.  How it works is fairly simple to imagine (though don't take this as a scientific explanation). Mass exists in spacetime and large amounts of mass pulls in spacetime. (Think bowling ball suspended in a sheet, except in 3 dimensions instead of just two).  As such when spacetime is pulled down, other smaller masses get pulled with it. Thus gravity.

[p1t1o]

1 hour ago, Green Baron said:

Now how does a chemist avoid gravity ?

:-)

Dunno, but find me a chemistry equation that includes the gravitational constant and Ill try and figure it out

[Green Baron]

I should think i can't even if i tried hard :-)

Was thinking more of a practical application, like spilling things to the floor rather than the ceiling :-))

Edit, well, on second thought, exothermal reaction, the stains on the ceiling or probably as numerous as those on the floor. Ok, you win !

Edited September 7, 2017 by Green Baron

[mikegarrison]

3 hours ago, p1t1o said:

Im a chemist by training so for me gravity doesnt exist.

Yeah. In fluid dynamics, the great division is between hydrodynamics, for which gravity is key and all compressibility terms are ignored, and aerodynamics, for which compressibility is key and all gravity terms are ignored.

[wumpus]

3 hours ago, p1t1o said:

Dunno, but find me a chemistry equation that includes the gravitational constant and Ill try and figure it out

Lighting a match/candle in zero g is said to be pretty weird.  The flame/plasma is spherical, and after it consumes the immediate air around it, it suffocates (no gravity, no convection and no new oxygen).  Then again, lighting a match/candle in 1g is complicated enough (if it requires gravity, you can imagine the interaction of plasma with the chaotic motion of convection.  Complicated).

4 hours ago, Steel said:

The discovery of the Higgs reveals pretty much nothing about gravity. It confirms Higgs' (not forgetting Anderson, Brout, Englert, Guralnik, Hagen, Kibble and 't Hooft) theory about why some particles have a small amount of intrinsic mass and that's about it (well that's not really it, but there's nothing else really worth highlighting here)

Knowing a bit more about rest mass doesn't help with gravity?  Gravity is getting fractally weird.  Even looking into a small part of it is as weird as the overall nature of our understanding of gravity.

[Vanamonde]

After spending his life expanding our knowledge of the universe, Einstein called gravity "spooky action at a distance." 

Yeah, that's right. Even Al couldn't wrap his head around it. 

[Steel]

2 minutes ago, wumpus said:

Knowing a bit more about rest mass doesn't help with gravity?  Gravity is getting fractally weird.  Even looking into a small part of it is as weird as the overall nature of our understanding of gravity.

No, because all it tells us is what the fundamental interaction is that gives intrinsic mass, not what effect that mass then has on other massive particles.

[p1t1o]

1 minute ago, wumpus said:

Lighting a match/candle in zero g is said to be pretty weird.  The flame/plasma is spherical, and after it consumes the immediate air around it, it suffocates (no gravity, no convection and no new oxygen).  Then again, lighting a match/candle in 1g is complicated enough (if it requires gravity, you can imagine the interaction of plasma with the chaotic motion of convection.  Complicated).

The reaction proceeds in precisely the same way though. Lack of convection changes the concentration environment but I think that is where the border is with chemical engineering. I just need the number of molecules in a given space and how fast are they moving

[Mr. Quark]

1 minute ago, Vanamonde said:

After spending his life expanding our knowledge of the universe, Einstein called gravity "spooky action at a distance." 

Yeah, that's right. Even Al couldn't wrap his head around it. 

you just called albert einstein "Al"

[Steel]

1 minute ago, Vanamonde said:

After spending his life expanding our knowledge of the universe, Einstein called gravity "spooky action at a distance." 

Yeah, that's right. Even Al couldn't wrap his head around it. 

No, "spooky action at a distance" was quantum entanglement. Einstein had a pretty good grasp on gravity.

[Mr. Quark]

3 posts at the same time 0-0

[Vanamonde]

1 minute ago, Steel said:

No, "spooky action at a distance" was quantum entanglement. Einstein had a pretty good grasp on gravity.

Well, spit. 

[Just Jim]

49 minutes ago, Vanamonde said:

Yeah, that's right. Even Al couldn't wrap his head around it. 

If I remember right, it was the possibility of black holes that really messed him up. His theory said they should exist, but he just couldn't accept the idea at the time. 

Edited September 7, 2017 by Just Jim

[sevenperforce]

Objects don't just pull on each other.

Time is generally understood to be the fourth dimension of space, forming something we call spacetime. The difference between time and the three spatial dimensions, one would assume, is that time is constantly in motion, while space is not. But that's not actually true. In completely empty space, the three spatial dimensions move through time at a constant "rate", but once you introduce localized sources of energy, the dimensions decrease down their motion through time and begin moving relative to each other. Each dimension moves perpendicular to the other two spatial dimensions.

All three dimensions moving perpendicular to each other produces what can be regarded as the "curvature of space", simply because when you move toward something that is perpendicular to you, you curve.

Gravitational time dilation is caused by the decrease in moving-through-time you experience when space is moving. Same with relativistic time dilation, except you're moving through space.

Why does energy cause the spacetime fabric to decrease its movement through time and start moving through space itself?

Now THAT'S a good question.

[Green Baron]

20 minutes ago, Just Jim said:

If I remember right, it was the possibility of black holes that really messed him up. His theory said they should exist, but he just couldn't accept the idea at the time. 

What people do who have too much time (*looking around*): analyse others :-) Here: https://arxiv.org/pdf/1301.1656.pdf

Furthermore he was uncomfortable with the idea that the universe could be open, a cosmological constant > 0 wasn't exactly his thing. The universe ought to be static and solemn (does that smell German ?). But then Hubble discovered another galaxy outside ours, that stirred things up.

Man, don't take me too serious here, i have too much time as well :-)

Edited September 7, 2017 by Green Baron