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StandardsGuy
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Two black holes that are orbiting and collide give off mass in the form of gravitational waves before the collision. Do these waves get absorbed by something, or is this mass lost to the universe?
The mass is given off, as you say, exactly as it is the case when accretion disks give off some of their energy as photons. In both cases, the thing "given off" just keeps on traveling through the universe (unless and until it encounters an object that impedes it (such as the LIGO detector, in the case of gravity wave), but the amount of the total wave given off (from the merger) that LIGO impedes is WAY below negligible.StandardsGuy said:Two black holes that are orbiting and collide give off mass in the form of gravitational waves before the collision. Do these waves get absorbed by something, or is this mass lost to the universe?
But they DON'T give off mass, they give off energy (if you're talking about gravitational waves) and that is attenuated when it travels through an expanding universe such as the one we live in.StandardsGuy said:But I am trying to understand if mass (however small it is) is lost. If you knew if the universe is finite or if you knew if it is infinite, would it change your answer? Does the wave going through objects add mass to the object?
Maybe you are a visual learner. What happens to the photons given off by this conversion of mass to energy that make it to space? Does that help clarify?StandardsGuy said:You are arguing semantics and adding little of value. My questions are still unanswered. The black holes have given up a lot of mass. OK it is changed to energy in the form of gravitational waves. OK it spreads out. If these waves were electromagnetic waves, they would be absorbed by objects and likely changed to heat. What do the gravitational waves do? If you don't know say so. I can accept that, but don't keep patronizing me. With the expanding universe they may just add to the energy of the vacuum. Perhaps this is the energy that is expanding the universe. Thoughts?
No. Electromagnetic waves are photons. Gravitational waves are "geometry" according to other threads on this site. There MAY be something called a graviton involved. Do gravitational waves add mass if/when they are absorbed?berkeman said:Maybe you are a visual learner. What happens to the photons given off by this conversion of mass to energy that make it to space? Does that help clarify?
https://sciencing.com/effects-hydrogen-bomb-5399698.html
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Actually, you beat me to my trying to edit my reply. It looks like gravitational waves are not absorbed by much of anything...StandardsGuy said:No. Electromagnetic waves are photons. Gravitational waves are "geometry" according to other threads on this site. There MAY be something called a graviton involved. Do gravitational waves add mass if/when they are absorbed?
Gravitational waves will change astronomy because the universe is nearly transparent to them: intervening matter and gravitational fields neither absorb nor reflect the gravitational waves to any significant degree. Humans will be able to observe astrophysical objects that would have otherwise been obscured, as well as the inner mechanisms of phenomena that do not produce light. For example, if stochastic gravitational waves are truly from the first moments after the Big Bang, then not only will we observe farther back into the history of the universe than we ever have before, but we will also be seeing these signals as they were when they were originally produced.
StandardsGuy said:Two black holes that are orbiting and collide give off mass in the form of gravitational waves before the collision. Do these waves get absorbed by something, or is this mass lost to the universe?
Was it LIGO that detected a gravitational wave from merging black holes.StandardsGuy said:You are even more patronizing than phinds. Your example has nothing to do with gravitational ________. (can you fill in the blank?) My question was what happens to the energy? Does it get absorbed? If so, in what form?
Most of the universe seems to be pretty transparent to gravitational waves. However, there is some small interaction, which is what is detected by LIGO. The waves are waves of spacetime curvature and spacetime curvature is closely tied to tidal gravity. Tidal effects can accelerate, decelerate, and heat matter, so all of those can happen with gravitational waves. But it is normally a very small amount.StandardsGuy said:What do the gravitational waves do?
StandardsGuy said:Do these waves get absorbed by something, or is this mass lost to the universe?
StandardsGuy said:The black holes have given up a lot of mass. OK it is changed to energy in the form of gravitational waves.
StandardsGuy said:If these waves were electromagnetic waves, they would be absorbed by objects
StandardsGuy said:What do the gravitational waves do?
StandardsGuy said:With the expanding universe they may just add to the energy of the vacuum.
StandardsGuy said:Perhaps this is the energy that is expanding the universe.
NC_Seattle said:My understanding, based on Feynman's 'sticky bead argumant' is that gravity waves do transfer energy to mass they pass through.
Actually only about ##10^{-16}## of the sky is stars. Some more might be absorbed by dust or gas.StandardsGuy said:If these waves were electromagnetic waves, they would be absorbed by objects and likely changed to heat.
NC_Seattle said:Furthermore, if the 'closed universe' model is correct then those gravity waves will continue bouncing (refracting?) around the universe,
again, bouncing off what ?NC_Seattle said:If our universe has a static ending (steady state) then the gravity waves will keeping bouncing around
I like your answer except perhaps the last sentence. Each incidence is a very small amount because it is spread out, but the number of incidences goes up exponentially for the same reason. But maybe you meant each incident absorbes a small amount of what's there?Dale said:Most of the universe seems to be pretty transparent to gravitational waves. However, there is some small interaction, which is what is detected by LIGO. The waves are waves of spacetime curvature and spacetime curvature is closely tied to tidal gravity. Tidal effects can accelerate, decelerate, and heat matter, so all of those can happen with gravitational waves. But it is normally a very small amount.
As I noted above, the chance of hitting anything is ##10^{-16}##. Space is very empty.StandardsGuy said:Each incidence is a very small amount because it is spread out, but the number of incidences goes up exponentially for the same reason.
This reminds me a bit of the Olber Paradox but the other way round.StandardsGuy said:I like your answer except perhaps the last sentence. Each incidence is a very small amount because it is spread out, but the number of incidences goes up exponentially for the same reason. But maybe you meant each incident absorbes a small amount of what's there?
Thanks for your answers. The mass is changed to equivalent energy so there is conservation, and there seems to be a consensus that it won't be changed back. Mass itself is less in the universe, so the attraction of gravity for it is gone, I think. That is not the case for two stars colliding to create a black hole. The gravity still exists in that case (but the mass is also gone).PeterDonis said:Exactly. Nothing is lost. So what's the problem?
My understanding is by the current theory it is called "dark energy", but I won't pursue it further.PeterDonis said:There is no such thing as "the energy that is expanding the universe". And in any case the expansion of the universe is a separate topic from the topic of this thread.
StandardsGuy said:The mass is changed to equivalent energy so there is conservation
StandardsGuy said:there seems to be a consensus that it won't be changed back.
StandardsGuy said:Mass itself is less in the universe, so the attraction of gravity for it is gone, I think. That is not the case for two stars colliding to create a black hole. The gravity still exists in that case (but the mass is also gone).
Delta2 said:I thought that gravitational waves are absorbed by masses, pretty much like EM waves interact and absorbed by electric charges... Why this is not the case?
stefan r said:I can not say that I know enough about gravitational waves to be certain that energy is never transferred anywhere.
Gravitational waves are ripples in the fabric of space-time that are created by the acceleration of massive objects, such as black holes or neutron stars.
Gravitational waves are detected using specialized instruments called interferometers, which measure tiny changes in the distance between two objects caused by passing gravitational waves.
Gravitational waves continue to travel through space at the speed of light, carrying energy away from the source of their creation. As they travel, they become weaker and eventually dissipate.
No, gravitational waves cannot be used for communication as they are incredibly weak and difficult to detect. Additionally, they are distorted and scattered by the matter they encounter, making them unreliable for communication purposes.
Studying gravitational waves can help us better understand the universe and its origins. By observing the properties of gravitational waves, we can learn more about the objects and events that create them, such as black holes and supernovae. This can also provide insights into the fundamental laws of physics and potentially lead to new discoveries.