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RE: Why is there gravity?
March 28, 2015 at 10:35 am
(This post was last modified: March 28, 2015 at 10:51 am by Alex K.)
Yeah, with why questions, there's always the question what kind of answer would even be possible. Often, "why" questions in every day life work like this - something happens, and you try to find the part of the causal relationship that is most relevant, thus tracing what happened back to other events. Or there's an established rule which allows us to trace back reasons to conditions in that rule. Like, why did I get a speeding ticket? Because I was going 100 in an 80 zone.
With things as fundamental as gravity, and existence questions, that's not so easy. What one can do, and the others have already done that nicely here, is to give an explanation inspired by our currently best theories. Of course, this answer to the why question will change somewhat when new theories are developed.
Explanations from theory don't answer the why question in a temporal fashion (as in: how did it come to pass that our universe has gravity) but rather attempt to trace the phenomenon back to more fundamental principles and descriptions of what is going on. However, nothing keeps you from again asking - why is that? like a 4 year old, and there wouldn't be an answer.
With gravity, it's currently this explanation from general relativity: All Energy, including mass, leads to the curvature of spacetime. Objects moving in curved spacetime get diverted and accelerated. Hence, gravitational attraction occurs.
(Why is that so? It just is...)
100 years ago, the explanation would have been less of an explanation: massive objects attract each other with a force which goes like 1/distance squared.
Maybe in a 100 years time, when we better understand the quantum nature of spacetime, the explanation will again read somewhat differently. Already today, one can attempt a quantum version of general relativity (which breaks down at the Planck scale). In this interpretation of the theory, gravitational force arises in analogy to electromagnetic force, because Gravitons are exchanged between objects.
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RE: Why is there gravity?
March 28, 2015 at 10:59 am
I have been working on a theory for several years that mass is basically cavitated space-time and gravity is the pressure of spacetime pushing back.
 hock: you say? Think about it. Nothing can escape a black hole. Except gravity? Does it not make more sense that gravity is pushing into the black hole? Once the event horizon is crossed, there is nothing as the matter has collapsed.
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RE: Why is there gravity?
March 28, 2015 at 11:01 am
I have no idea. Show the maths and we'll talk...
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Why is there gravity?
March 28, 2015 at 11:05 am
(March 28, 2015 at 10:10 am)vorlon13 Wrote: Our universe just barely has gravity.
Really.
It is ASTONISHINGLY weak.
Think about it, the ENTIRE earth is pulling on your kids report card and the puny little teeny tiny Scooby Doo refrigerator magnet COMPLETELY overpowers it !!!!!!!!!
Gravity ?? Meh !!!
Jump off a tall building with a magnet in your hand and see if it saves you. What will you think of gravity when you fall? Will it be Meh !!! ?
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RE: Why is there gravity?
March 28, 2015 at 11:17 am
No, but in the end, it will be electromagnetism that makes you go *splash*
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RE: Why is there gravity?
March 28, 2015 at 11:23 am
(March 28, 2015 at 11:01 am)Alex K Wrote: I have no idea. Show the maths and we'll talk...
The math is basically the same. We still have identical issues with what caused the cavitation versus what caused the explosion.
Here are a couple of links with a similar perspective. I have tossed around a couple of ideas with both parties.
http://www.simplegravity.com/
http://www.dcgeorge.com/TheCavitationThe...ter_f.html
Everything I have is handwritten. I have yet to get around to putting in the computer. I like paper. Originally, it was supposed to be my thesis, but one thing led to another and ...
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RE: Why is there gravity?
March 28, 2015 at 11:26 am
(This post was last modified: March 28, 2015 at 11:43 am by Anomalocaris.)
(March 28, 2015 at 11:05 am)KUSA Wrote: (March 28, 2015 at 10:10 am)vorlon13 Wrote: Our universe just barely has gravity.
Really.
It is ASTONISHINGLY weak.
Think about it, the ENTIRE earth is pulling on your kids report card and the puny little teeny tiny Scooby Doo refrigerator magnet COMPLETELY overpowers it !!!!!!!!!
Gravity ?? Meh !!!
Jump off a tall building with a magnet in your hand and see if it saves you. What will you think of gravity when you fall? Will it be Meh !!! ?
Using magnets, taking advantage of the dipole nature of water molecules in your cells, to levitate you against earth's gravity? It can certainly be done.
Here is it being done to a frog:
![[Image: kikker-groot.jpg]](https://images.weserv.nl/?url=www.ru.nl%2Fpublish%2Fpages%2F682806%2Fkikker-groot.jpg)
(March 28, 2015 at 11:17 am)Alex K Wrote: No, but in the end, it will be electromagnetism that makes you go *splash*
Yes, but the pieces still come back down to earth, yoked to gravity as they are.
It takes the liberatable electromagnetic energy in about 3000 tons of stuff to wrestle 20 tons of stuff out of clutches of earth's gravity. 
I wonder what is the ratio between total chemical energy available in the earth and earth's gravitational binding energy. I suspect earth's gravitational binding energy exceeds total available chemical energy by a large amount. Even if earth was made all of TNT, setting all that off won't unbind the earth.
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RE: Why is there gravity?
March 28, 2015 at 11:29 am
(This post was last modified: March 28, 2015 at 11:29 am by Alex K.)
(March 28, 2015 at 11:26 am)Chuck Wrote: (March 28, 2015 at 11:17 am)Alex K Wrote: No, but in the end, it will be electromagnetism that makes you go *splash*
Yes, but the pieces still come back down to earth, yoked to gravity as they are.
Look at it this way though: the momentum that gravity needs a 100 feet falling distance to gather, will be stopped by electromagnetism in a millimeter.
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RE: Why is there gravity?
March 28, 2015 at 11:31 am
(March 28, 2015 at 11:05 am)KUSA Wrote: Jump off a tall building with a magnet in your hand and see if it saves you. What will you think of gravity when you fall? Will it be Meh !!! ? Set up properly, it would probably work quite well. Have you tried pushing two Neodymium magnets together or pulling them apart?
You make people miserable and there's nothing they can do about it, just like god.
-- Homer Simpson
God has no place within these walls, just as facts have no place within organized religion.
-- Superintendent Chalmers
Science is like a blabbermouth who ruins a movie by telling you how it ends. There are some things we don't want to know. Important things.
-- Ned Flanders
Once something's been approved by the government, it's no longer immoral.
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RE: Why is there gravity?
March 28, 2015 at 11:36 am
(This post was last modified: March 28, 2015 at 11:39 am by Anomalocaris.)
(March 28, 2015 at 11:29 am)Alex K Wrote: (March 28, 2015 at 11:26 am)Chuck Wrote: Yes, but the pieces still come back down to earth, yoked to gravity as they are.
Look at it this way though: the momentum that gravity needs a 100 feet falling distance to gather, will be stopped by electromagnetism in a millimeter.
Well, I suspect even electromagnetism will need quite a few more than one millimeter to stop a body that has fallen 100 feet.
(March 28, 2015 at 11:31 am)IATIA Wrote: (March 28, 2015 at 11:05 am)KUSA Wrote: Jump off a tall building with a magnet in your hand and see if it saves you. What will you think of gravity when you fall? Will it be Meh !!! ? Set up properly, it would probably work quite well. Have you tried pushing two Neodymium magnets together or pulling them apart?
That's how maglev train works. Permanent neodymium magnets working against electromagnets.
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