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Author Topic: Where does gravity come from?  (Read 9028 times)

Nhlanhla A. Mdhlalose

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Where does gravity come from?
« on: 20/11/2011 12:01:02 »
Nhlanhla A. Mdhlalose  asked the Naked Scientists:
   
Where does gravity come from? I thought it was the moon.

Did it exist before the big bang or after?

Thank you doctor.

Regards
Nhlanhla

What do you think?
« Last Edit: 20/11/2011 12:01:02 by _system »


 

Offline yor_on

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Where does gravity come from?
« Reply #1 on: 20/11/2011 21:01:49 »
Gravity just seem to be here. Without it not much would make sense, Einstein defined is as a "SpaceTime geometry" as I understands it (coupled to mass, and possibly 'energy' whatever that is?), and that works for me. Why a geometry differs between 'up and down' though? :)
=

As for if it existed before the Big Bang?
A very good question, I don't know, but I sure wish I did. Maybe it is a function of the 'room and time geometry' we exist in, maybe it is something else.
« Last Edit: 20/11/2011 21:08:54 by yor_on »
 

Offline Soul Surfer

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Where does gravity come from?
« Reply #2 on: 20/11/2011 23:00:59 »
Gravity does not really come from anywhere it is just part of the behaviour of the stuff that makes up the universe.  It is important that it is so weak that it allows the universe to be very big and last for a long time.  however if the physical laws evolved on the basis that maximises longevity and complexity. One very weak force is to be expected.
 

Offline Silver

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Where does gravity come from?
« Reply #3 on: 22/11/2011 17:19:36 »
Gravity is a property of all matter which suggests that it comes from matter itself.

The idea with the big bang is that gravity did not exist originally (meaning that the original singularity was not held together by gravity at any point). If gravity comes from matter, then it would have appeared when matter appeared.
 

Offline MikeS

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Where does gravity come from?
« Reply #4 on: 23/11/2011 09:03:31 »
Gravity is a property of all matter which suggests that it comes from matter itself.

The idea with the big bang is that gravity did not exist originally (meaning that the original singularity was not held together by gravity at any point). If gravity comes from matter, then it would have appeared when matter appeared.

I agree.

Again I personally agree but this is not a mainstream view.  According to GR energy also creates gravity.  If this is the case then the universe was born with its full compliment of gravity but without matter it would have been very diffuse. 

Although energy is supposed to curve space-time, I have not been able to find any experimental evidence to confirm this.
« Last Edit: 23/11/2011 09:14:55 by MikeS »
 

Offline Supercryptid

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Where does gravity come from?
« Reply #5 on: 23/11/2011 20:37:57 »
Quote
Again I personally agree but this is not a mainstream view.  According to GR energy also creates gravity.  If this is the case then the universe was born with its full compliment of gravity but without matter it would have been very diffuse. 

Although energy is supposed to curve space-time, I have not been able to find any experimental evidence to confirm this.

There was something that I realized not so long ago; if the unified field theory is correct, then gravity shouldn't have existed at the moment of the Big Bang because the temperature would have been so high that it would be unified with the other forces. There would have been only one superforce governing the actions of energy and matter. Has anyone managed to make predictions about the superforce? Would it behave like gravity at all? If it was strongly repulsive, then that might help explain why the Big Bang went "bang" in the first place...
 

Offline CZARCAR

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Where does gravity come from?
« Reply #6 on: 23/11/2011 21:03:30 »
GRAVITONS! maybe
 

Offline Silver

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Where does gravity come from?
« Reply #7 on: 24/11/2011 16:06:28 »
MikeS. The elephant in the room of cosmology and physics is: "What is space?"

There are no explanations of how it can expand from quantum size to present size without changing in any way or how it suddenly becomes rigid enough to be curved by mass instead of mass just sucking the lot in.

Space like dark matter is just an idea that does whatever is required of it without anyone knowing what it is.

I tend to think of it as literally nothing, and that like magnetism, gravity does not need to be "conducted" through a material called space to work.

Energy tends to come with matter so saying it alone can cause gravity is an idea.
 

Offline Silver

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Where does gravity come from?
« Reply #8 on: 24/11/2011 16:11:12 »
Supercryptid. Once gravity appears in any form, why is the big bang going to continue inflating or expanding?

Black holes are not impressed by any amount of heat. Or force.
 

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Where does gravity come from?
« Reply #8 on: 24/11/2011 16:11:12 »

 

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