# Sun Vanishes - How Long Till Orbits Change?

• jwestall
In summary, the question of how long it would take for the Earth to stop orbiting if all particles in the sun simultaneously tunneled to another galaxy does not have a clear answer as there is no solution in Einstein's equations for this scenario. However, if the sun were to slowly be pulled away, the effect would spread at the speed of light and could potentially be noticeable after approximately 8 minutes. There have been attempts to measure the speed of gravity, but there is currently no conclusive evidence for its exact speed.
jwestall
I've wanted to know this for 15 years. If every particle in the sun simultaneously tunneled to another galaxy, how long would it take the Earth to stop orbiting as if the sun were there? 0 seconds? ~7 minutes? Why? How fast does space-time un-deform?

~8 minutes. The speed of gravity is the same as the speed of light, according to General relativity.

Matterwave said:
~8 minutes. The speed of gravity is the same as the speed of light, according to General relativity.
1 vote for the 'speed of light' column. Would there be any practical way to test this? Or has such a test already happened and I just don't know about it? As I understand it, general relativity said that basically nothing can happen faster than speed of light in vacuum, including the transmission of information, but now we say that entwined particles somehow break this rule. Thanks for the reply!

jwestall said:
Or has such a test already happened and I just don't know about it? Thanks for the reply!

And you will not know for about 8 minutes.

*rushes to eBay to sell his Magic: the Gathering collection* Thanks for the post!

From http://en.wikipedia.org/wiki/Speed_of_gravity[/b]

"Several physicists, including Clifford M. Will and Steve Carlip, have criticized these claims on the grounds that they have allegedly misinterpreted the results of their measurements. Notably, prior to the actual transit, Hideki Asada in a paper to the Astrophysical Journal Letters theorized that the proposed experiment was essentially a roundabout confirmation of the speed of light instead of the speed of gravity. [15] Further, there has been criticism of the means by which these results were presented, in that they were announced at a meeting of the AAS instead of being submitted for peer review. [16] However, Kopeikin and Fomalont continue to vigorously argue their case and the means of presenting their result at the press-conference of AAS that was offered after the peer review of the results of the Jovian experiment had been done by the experts of the AAS scientific organizing committee. Asada's claim was found theoretically unsound and disproved in later publication by Kopeikin and Fomalont [17], which operates with a bi-metric formalism that splits the space-time null cone in two - one for gravity and another one for light. The two null cones overlap in general relativity, which makes tracking the speed-of-gravity effects difficult and requires a special mathematical technique of gravitational retarded potentials, which was worked out by Kopeikin and co-authors [18][19] but was never properly employed by Asada and/or the other critics."

Suffice it to say, this clearly isn't something a total layman is going to understand this side of a physics degree. *sigh*

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I think the gist of it is, we see a delay in response time, but is that delay due to the finite speed of gravity or the finite speed of light? Both effects must be considered.

The details are quite complicated however...

[/PLAIN]

jwestall said:
"Several physicists, including Clifford M. Will and Steve Carlip, have criticized these claims on the grounds that they have allegedly misinterpreted the results of their measurements. Notably, prior to the actual transit, Hideki Asada in a paper to the Astrophysical Journal Letters theorized that the proposed experiment was essentially a roundabout confirmation of the speed of light instead of the speed of gravity. [15] Further, there has been criticism of the means by which these results were presented, in that they were announced at a meeting of the AAS instead of being submitted for peer review. [16] However, Kopeikin and Fomalont continue to vigorously argue their case and the means of presenting their result at the press-conference of AAS that was offered after the peer review of the results of the Jovian experiment had been done by the experts of the AAS scientific organizing committee. Asada's claim was found theoretically unsound and disproved in later publication by Kopeikin and Fomalont [17], which operates with a bi-metric formalism that splits the space-time null cone in two - one for gravity and another one for light. The two null cones overlap in general relativity, which makes tracking the speed-of-gravity effects difficult and requires a special mathematical technique of gravitational retarded potentials, which was worked out by Kopeikin and co-authors [18][19] but was never properly employed by Asada and/or the other critics."

Suffice it to say, this clearly isn't something a total layman is going to understand this side of a physics degree. *sigh*

This is a claim made a few years back to be a actual measurement of the speed of gravity. It turned out to be in error. The speed of gravity remains unmeasured, it is predicted by theory to be the same as c.

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Matterwave said:
I think the gist of it is, we see a delay in response time, but is that delay due to the finite speed of gravity or the finite speed of light? Both effects must be considered.

The details are quite complicated however...

I learned a long time ago, when a physics geek says "complicated", that means "hide under the bed and suck your thumb." Thanks for the post ;)

[/PLAIN]

Thanks for the post, Integral. I'll put this on my list of questions to ask God, should I get the chance.

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There are some old threads about this, so you might want to search for them too. It's not correct to just answer this question with "8 minutes", because there's no solution of Einsteins equation that describes spacetime around a star that just vanishes. So the question doesn't make sense as it stands. You can however imagine the sun being pulled away slowly, and in that case, the effect spreads at the speed of light and will therefore be noticeable about 8 minutes after you start.

Fredrik said:
There are some old threads about this, so you might want to search for them too. It's not correct to just answer this question with "8 minutes", because there's no solution of Einsteins equation that describes spacetime around a star that just vanishes. So the question doesn't make sense as it stands. You can however imagine the sun being pulled away slowly, and in that case, the effect spreads at the speed of light and will therefore be noticeable about 8 minutes after you start.

It is definitely an intentional part of my question that this is *NOT* a gradual change. Let's say this is a weapon of an advanced, alien civilization. I want to know what happens when the source is just GONE, not moving at a pleasant, manageable <c.

You could rephrase this as "Aliens threaten to instantly tunnel all of Sagittarius A* to the edges of the universe. How long do human technologists have to respond?"

Thanks for the post!

There are no known mechanisms by which matter/energy could just be gone. If an advanced civilization annihilated the Sun completely, it would all be converted into energy and this energy would still be deforming space-time.

If you are talking about tunneling, there is no way the Sun can "tunnel" to somewhere else since it's a macroscopic object, always being "observed" and interacting with other objects in such a way that its wavefunction will not have time to diffuse according to the Schrodinger equation.

If you are talking about say, the gravity of a particle which may tunnel, then i have no idea. The general theory of relativity has not been brought together with Quantum mechanics. It's actually one of the main points of study at this time.

Matterwave said:
There are no known mechanisms by which matter/energy could just be gone. If an advanced civilization annihilated the Sun completely, it would all be converted into energy and this energy would still be deforming space-time.

If you are talking about tunneling, there is no way the Sun can "tunnel" to somewhere else since it's a macroscopic object, always being "observed" and interacting with other objects in such a way that its wavefunction will not have time to diffuse according to the Schrodinger equation.

If you are talking about say, the gravity of a particle which may tunnel, then i have no idea. The general theory of relativity has not been brought together with Quantum mechanics. It's actually one of the main points of study at this time.

Thanks for the post. I want to know, but not so much I'm about to dive into superstrings or M theory or the such. I think I'll focus on trying to understand what "time to diffuse according to the Schrodinger equation" means for now.

Any particle can be described by it's wavefunction which evolves according to the Schrodinger equation. The Schrodinger equation tends to smear out the wave function over time (the wave packet tends to grow flatter and wider) since, in form the Schrodinger equation is very similar to a diffusion equation, unless something is preventing this from occurring, such as wavefunction collapse (or if the particle is stuck in some sort of potential well).

jwestall said:
It is definitely an intentional part of my question that this is *NOT* a gradual change. Let's say this is a weapon of an advanced, alien civilization. I want to know what happens when the source is just GONE, not moving at a pleasant, manageable <c.

You could rephrase this as "Aliens threaten to instantly tunnel all of Sagittarius A* to the edges of the universe. How long do human technologists have to respond?"
I didn't change your question to make it easier to answer. I changed it because it didn't make sense.

Regarding your new question, the answer would depend on how the sun is moved. If it's through a wormhole, we're still dealing with a star that moves away slowly (through the wormhole) so my previous answer still applies, and you would have to add the contribution from the wormhole.

jwestall said:
It is definitely an intentional part of my question that this is *NOT* a gradual change.
Much of physics is based on the assumption of energy conservation, which would be violated by this premise. So basically you are asking:

"What would the laws of physics predict, if the laws of physics were wrong?"

A.T. said:

"What would the laws of physics predict, if the laws of physics were wrong?"
Well said.

Fredrik said:
I didn't change your question to make it easier to answer. I changed it because it didn't make sense.

Regarding your new question, the answer would depend on how the sun is moved. If it's through a wormhole, we're still dealing with a star that moves away slowly (through the wormhole) so my previous answer still applies, and you would have to add the contribution from the wormhole.

The problem with hypothetical but impossible questions like this is that they are contradictory with theory. Literally anything can be derived from a contradiction, so these questions are impossible to answer without modification.

Edit: I see the contradiction has been stated above .

## 1. What would happen if the sun suddenly vanished?

If the sun suddenly vanished, we would experience complete darkness and a sudden drop in temperature. This is because the sun is our primary source of light and heat.

## 2. How long would it take for the Earth's orbit to change if the sun vanished?

If the sun vanished, the Earth's orbit would not change immediately. It would continue to move in a straight line at a constant speed due to its inertia. However, over time, the Earth's orbit would be affected by the gravitational pull of other planets and stars, causing its trajectory to change.

## 3. Would the disappearance of the sun affect other planets in our solar system?

Yes, the disappearance of the sun would have a significant impact on all the planets in our solar system. As the sun is the largest and most massive object, its absence would cause the entire solar system to become unbalanced, affecting the orbits of other planets.

## 4. How long would it take for life on Earth to become extinct if the sun vanished?

If the sun vanished, it would take approximately 8 minutes and 20 seconds for the effects to reach Earth, as that is how long it takes for sunlight to travel from the sun to Earth. Without the sun's heat and light, the Earth would become uninhabitable within a few weeks or months.

## 5. Is it possible for the sun to suddenly vanish?

No, it is not possible for the sun to suddenly vanish. The sun is a stable star and is expected to last for another 5 billion years. It would require a catastrophic event, such as a supernova or a collision with another star, to make the sun disappear. These events are highly unlikely to occur in the near future.

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