Physics Question

[chapeau]

quantum mechanics would permit every subatomic particle of the sun to up sticks and move across the universe en-masse but it's not likely to happen soon.

 

[UriBentMySpoon]

You are missing the point of the question. It is a thought experiment if you like. It is about getting people to think about gravity and whether it has a speed in its influence or whether the removal or adding of a gravitational body effects everything in an instant.

It is not meant to be a realistic situation, just a way of getting people to ponder what is Gravity.

he's only doing what you did in the would you shoot thread uri.

Er no. What I was asking was for clarifiocation on your question, wheteher or not I was executing an innocent man. When that was clarified I gave you my answer. I was not pointing out that time travel is impossible and therefore the question was invalid I was taking your question as the thought experiment it was meant to be.

 

[joe-90]

Well what would happen to that gravity if both the sun and earth were to disappear at the same time? If you cannot answer - then I am right. Simples.

Hey Chappy - I'm waiting for an answer.

 

[UriBentMySpoon]

Fred Watson in his book Why is Uranus upside down? provides an answer to the what is the speed of gravity question, his answer, like the others I have found online go towards gravity being equal to the speed of light, so we would need to wait for the tension wave ibn the metaphorical string to reach us.

 

[noseall]

Well what would happen to that gravity if both the sun and earth were to disappear at the same time? If you cannot answer - then I am right. Simples.

Hey Chappy - I'm waiting for an answer.

Why don't you start a new thread Joe.

How does not being able to answer your new question make you correct on the o.p. question?

You are as baffling as you are bonkers Joe.

 

[joe-90]

Because the answer to one refutes the answer to the other.

 

[UriBentMySpoon]

I do not know if your question is realting to my original question Joe? Is it?

If both the Sun and Earth were to go instantly, then my understanding of what ths scientist bods think, there will be ripples from both the areas where the Sun and the Earth were, which would eventually smooth out to nothingness, no gravity pulling either way. To use the rubber sheet example that is popular when discussiong gravity fields, remove the weights and the rubber sheet would bounce up and down until the sheet comes to a standstill.

Does not answer the original question though.

 

[noseall]

Because the answer to one refutes the answer to the other.

How does it?

The o.p's question is asking about the theoretical effects of one gravitational body on another, when ONE of those is removed/disappears.

Take them both away and you don't have a question anymore.

It seems that you are going off on one just to baffle or mislead.

 

[joe-90]

I do not know if your question is realting to my original question Joe? Is it?

If both the Sun and Earth were to go instantly, then my understanding of what ths scientist bods think, there will be ripples from both the areas where the Sun and the Earth were, which would eventually smooth out to nothingness, no gravity pulling either way. To use the rubber sheet example that is popular when discussiong gravity fields, remove the weights and the rubber sheet would bounce up and down until the sheet comes to a standstill.

Does not answer the original question though.

Space isn't a rubber sheet though is it? But the analogy is good. Gravity is the product of the distortion of space by mass. Take away the mass and you take away gravity. Gedditt yet? Take away the sun and you take away the distortion of space - hence no gravity. Use your noodle - not google.

 

[noseall]

[ Take away the sun and you take away the distortion of space - hence no gravity. Use your noodle - not google.

Yes but is it instant?

Take away the Sun, yet you can still feel the heat and still see it shining for a significant period of time afterwards.

How can you still feel the heat energy of something that stopped putting out heat a while back?

Same with gravy* fella.

*Deliberate smelling mistake.

 

[joe-90]

It doesn't work that way. Gravity isn't generated by the sun and sent to us as photons. Mass deforms space. Take away the deformation and you have no gravity. Gravity isn't being sent to us. Gedditt yt?

 

[noseall]

Gedditt yt?

No.

So how is this translated into distance, i.e. the further away the weaker it gets etc.

If distance has an effect then time must be involved therefore instant can not happen.

 

[joe-90]

Because space/time is deformed by the sun's mass. Further away the deformation is less.

Think bowling ball on a trampoline.

 

[joinerjohn]

Scientists reckon when the sun has used up most of it's hydrogen, it will expand rapidly to become a red giant, before eventually collapsing to become a white dwarf, then finally a supernova.

 

[sooey]

Scientists reckon when the sun has used up most of it's hydrogen, it will expand rapidly to become a red giant, before eventually collapsing to become a white dwarf, then finally a supernova.

That's right, (except for the supernova bit), for a star to collapse into a black hole it has to be 2 or 3 times bigger than our sun.
A little indian fella called Chandrasakar worked out exactly how massive they have to be on a boat to England, so it's called the Chandrasakar limit. Anything smaller doesn't have enough gravity to form a black hole.