Physics Question
- Thread starter UriBentMySpoon
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I did, as I already knew the answer, as I occasionally read scientific literature. Its just that evidence is kind of useful, so a quick search for references was called for.Try it sometime.
I note that you have provided zero evidence. Again.
As has already been pointed out, who would one rather trust: The scientific community, or some forum poster who provides zero evidence and some dodgy analogies.
Sun disappears, so does its gravitational effect, how soon would it take effect on the Earth. Should I have specified that?
The sun goes, so does its gravity, there is a wave as the changes in gravity take effect, this wave travels to us. As stated at the speed of light.
Yes you take away the mass you take away the gravity, everyone who has had a serious pop at this question understands this.
Using your brain power does not make you correct Joe, unless you are saying you are infallible?
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The Sun emits photons, packets of light energy. They take a few seconds to reach us from the sun. If the sun were to disappear then the packets would still be on their way to us until the last one reached us. Yes? Agreed?
Now tell what the name of the packets of gravity are called and how they cross space to reach us. How do they react with the earth when they do reach us? When the last packet of light reaches us - the earth goes dark and freezes. When the last packet of gravity reaches us - then what happens?
If you can answer that - then you prove me wrong.
However, if you are unable to answer that - then you prove me right.
Over to you.
Now tell what the name of the packets of gravity are called and how they cross space to reach us. How do they react with the earth when they do reach us? When the last packet of light reaches us - the earth goes dark and freezes. When the last packet of gravity reaches us - then what happens?
If you can answer that - then you prove me wrong.
However, if you are unable to answer that - then you prove me right.
Over to you.
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C
calorific
All this talk of evidence is of little value since we are dealing with hypotheticals which has no empirical evidence.
The problem I have with the suggestion that gravity travels at a particular speed is that it would imply that the sun in some way "generates" or "emits" gravity in the same way that it does with light. This implies that it creates some kind of force. I would again argue that gravity is a property of space rather than of a body within space and hence if the body is removed instantaneously as stated in the original proposition, then space no longer has this property instantaneously (the analogy of a ball on a sheet of rubber was one used by einstein himself and not some crackpot idea created by joe). Thus gravity disappears instantaneously and there is no delay before the earth moves differently.
An interesting bit of maths would actually be to consider doppler light effects given that the earth would suddenly be moving in a straighter line (subject to the usual other space bodies) whereas this 8 minutes of light would still be travelling in its original "straight line" (subject to the curvatures and anomalies of space).
The problem I have with the suggestion that gravity travels at a particular speed is that it would imply that the sun in some way "generates" or "emits" gravity in the same way that it does with light. This implies that it creates some kind of force. I would again argue that gravity is a property of space rather than of a body within space and hence if the body is removed instantaneously as stated in the original proposition, then space no longer has this property instantaneously (the analogy of a ball on a sheet of rubber was one used by einstein himself and not some crackpot idea created by joe). Thus gravity disappears instantaneously and there is no delay before the earth moves differently.
An interesting bit of maths would actually be to consider doppler light effects given that the earth would suddenly be moving in a straighter line (subject to the usual other space bodies) whereas this 8 minutes of light would still be travelling in its original "straight line" (subject to the curvatures and anomalies of space).
J
joinerjohn
Actually, light from the Sun takes about 8,1/2 minutes to reach the Earth , Joe,, Not a few seconds.
Er, Gravitons.
You clearly didn't understand Tonka's excellent post. No surprise there. After all, when he mentioned gluons you must have thought he was talking about what you sort out at the bidet.
And yes, I know you are going to have to google 'bidet'
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All of the fundamental forces have a gauge boson or force carrier. Photons for electromagnetic energy of which light is a tiny part of the spectrum, gluons for the strong nuclear force that holds quarks together to form baryons and mesons, w and z bosons for the weak nuclear force that is responsible for radioactive decay. The carrier for gravity is called the graviton. We haven't isolated it yet or seen it in experiments. All bosons are limited by the speed of light and that will be the speed of change.
If you go for the rubber sheet analogy, removal of the mass won't flatten the sheet instantaneously - there will be some hysteresis or inertia and that will result in the effect changing at a finite velocity. It turns out that that velocity is c or the speed of light in a vacuum.
We would see the effects of both light and other EM radiation and gravitational fields disappearing at the same time, i.e. a bit more than 8 minutes after the Sun miraculously vanished from our solar system.
Clearer?
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Tell me about a gravitron. What happens when the last wave of gravitrons reach the earth?
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Not a bit. When you do find it (if ever) then you can talk as if you know what you are talking about., until that time - it's just a silly theory.
Excellent summary again - but not at quite the same time though....
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Let's get down the the last 50 thou of a second shall we? The very last of the gravitrons is holding all the planets in place eh? Then a tiny fraction of a second later they all fly off into deep space? Is that right? Well tell me how that works then. And tell me where in the sun the gravitrons are emitted from.
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When the sun disappears everything carries as usual eh? Photons in transit reach us and keep us warm.
Then what? I guess that Mercury would be first to lose its gravitrons - so would it suddenly fly off at a tangent after about 3 minutes? Then Venus (whoops don't hit us - we are still in orbit).
What mechanism would hold the earth in place after the sun had gone?
Then what? I guess that Mercury would be first to lose its gravitrons - so would it suddenly fly off at a tangent after about 3 minutes? Then Venus (whoops don't hit us - we are still in orbit).
What mechanism would hold the earth in place after the sun had gone?
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Orbital inertia and the conservation of angular momentum.
You really haven't understood any of the explanations have you?
You really haven't understood any of the explanations have you?
Hmm that's an interesting thing to throw into the pot. Angular momentum does need to be conserved. So what would happen? Earth rotation change, distance between earth and moon change? Shouldn't have had those beers at St Pancras, head a bit fuzzy.....
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