How Does Gravity Work and What Causes Time to Slow Down Near a Black Hole?

In summary, the conversation discussed the concept of relativity of time and its effects in different scenarios. It was mentioned that time can be noticed in Earth in vertical time measurements, and the question of how long this would continue was raised. It was then discussed that in a black hole, gravity is unlimited and this causes time to slow down. It was also mentioned that speed can also slow down time, and in a black hole where speed increases near light speed, time would slow down significantly. The concept of gravitational time dilation was also brought up and it was stated that it is not proportional to the gravitational field intensity, but rather to the gravitational potential. The conversation then moved on to discussing how fast ticking would be in empty space and the distance at
  • #1
temoisio
7
0
About relativity of time. It can be noticed already in Earth in vertical time measurements. But how long it continues.

So what will happen in black hole to time. Gravity is unlimited, so ticks will slow down. And other thing, speed slows down the time. So in huge gravity, all speed will increase near light speed, so time would slow down. So from tick perspective, black hole would be the slowest ticker in universe.

How fast is ticking in really empty space. Will it be infinity or something close to our ticking. So what is the distance, that mass and gravity will effect to tick speed (in terms of gravity slowness).

To practical universe measurements. Now universe is widening, as measured with spectrum. But could relative time be big enough in larger scale (calaxy level), that it would effect to measurements? So as idea, it should look the same:
- Timetick speed is slower in calaxy (or a large star), redshift happens?
- Object is moving further, redshift happens
- And vice versa with blueshift and object moving closer

So if we compare example light of the sun to much bigger star, there should be some redshift. As bigger star has bigger gravity, and therefor slower time. But again, smaller star should have bluesift. So directly with this theory, if universe would not widen, all small stars should have bluesift and large stars should have redsift.
 
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  • #2
gravitational time dilation is not proportional to gravitational field intesity.
its proportional to gravitational potential

gravitational time dilation becomes infintite at the event horizon even though the gravitational field isn't infinitely strong there.

the rest of your post is incomprehensible gibberish
 
  • #3
temoisio said:
About relativity of time. It can be noticed already in Earth in vertical time measurements. But how long it continues.

So what will happen in black hole to time. Gravity is unlimited, so ticks will slow down. And other thing, speed slows down the time. So in huge gravity, all speed will increase near light speed, so time would slow down. So from tick perspective, black hole would be the slowest ticker in universe.

How fast is ticking in really empty space. Will it be infinity or something close to our ticking. So what is the distance, that mass and gravity will effect to tick speed (in terms of gravity slowness).

To practical universe measurements. Now universe is widening, as measured with spectrum. But could relative time be big enough in larger scale (calaxy level), that it would effect to measurements? So as idea, it should look the same:
- Timetick speed is slower in calaxy (or a large star), redshift happens?
- Object is moving further, redshift happens
- And vice versa with blueshift and object moving closer

So if we compare example light of the sun to much bigger star, there should be some redshift. As bigger star has bigger gravity, and therefor slower time. But again, smaller star should have bluesift. So directly with this theory, if universe would not widen, all small stars should have bluesift and large stars should have redsift.


What?
 
  • #4
Ok, actually there is test results now when googled:

"The first observation of the gravitational redshift was the measurement of the shift in the spectral lines from the white dwarf star Sirius B by Adams in 1925. Although this measurement, as well as later measurements of the spectral shift on other white dwarf stars, agreed with the prediction of relativity, it could be argued that the shift could possibly stem from some other cause, and hence experimental verification using a known terrestrial source was preferable ."

"A very accurate gravitational redshift experiment, which deals with this issue, was performed in 1976,[34] where a hydrogen maser clock on a rocket was launched to a height of 10,000 km, and its rate compared with an identical clock on the ground. It tested the gravitational redshift to 0.007%."

Yes, seems it's hard to measure from space, as there are other things effecting (maybe mostly movement).

But yes, this "earth test" was performed in 1976. So I could think there might be some more up to date information.

So i think answer is, that there are no studies those would provide results. And it is thought, that redsift from galaxy light means, it is moving away. Not, that there is time dilation.
 
  • #5
granpa said:
gravitational time dilation becomes infintite at the event horizon even though the gravitational field isn't infinitely strong there.

Yes, in black hole there is one thing confusing. There are findings written, that near black hole, hole itself can be confirmed, because it's gravity. But gravity itself is particles (or kvarts or waves), those can't travel out from black hole (nothing moves faster then light). So black hole should not have gravity at all.

So only thing black hole could do, is curve the time & space. But again that curving should be as well inside this light speed theory. So if there is a black hole, that should not have any effect to outside. As no force or wave or particle could come out from the black hole.

So time dilation could be only thing that black hole could do. So that would remain even nothing comes out from the black hole.

There can be answer to this if knowing how gravity works more detailed. But I haven't run any explanations about gravity of the black hole.
 
  • #6
temoisio said:
Yes, in black hole there is one thing confusing. There are findings written, that near black hole, hole itself can be confirmed, because it's gravity. But gravity itself is particles (or kvarts or waves), those can't travel out from black hole (nothing moves faster then light). So black hole should not have gravity at all.

So only thing black hole could do, is curve the time & space. But again that curving should be as well inside this light speed theory. So if there is a black hole, that should not have any effect to outside. As no force or wave or particle could come out from the black hole.

So time dilation could be only thing that black hole could do. So that would remain even nothing comes out from the black hole.

There can be answer to this if knowing how gravity works more detailed. But I haven't run any explanations about gravity of the black hole.

Huh?
 
  • #7
Hunter612 said:
Huh?

Ok. So,

How can gravity travel out from black hole? So:
- Black hole is a huge mass, it creates gravity around it
- Gravity is estimated to be particle or wave (graviton)

So how can black hole has gravity, when graviton should then travel out from black hole?

So some theory is not right :confused:
 
  • #8
Gravity is not mediated by real gravitons. Nothing has to escape the event horizon to produce a static gravitational field. Static fields carry no information.
 
  • #9
ok, tx. Yes seems wikipedia has some articles around this as well:
http://en.wikipedia.org/wiki/Static_forces_and_virtual-particle_exchange

Then there are theories like string theory:
http://en.wikipedia.org/wiki/String_theory

Yes just time would be easier to believe for now. But again it is estimated, that curving space time moves in speed of light as well. So basically it could not curve out from black hole. Then of course can be, that something happens in event horizon. That you can't actually tell outside black hole, how much mass there is.

But yes, as told in wikipedia, all other forces have been quite much understood, but not gravity. It's there but why.
 
  • #10
Say I'm someone without a clue, explain to me what gravity is and how it works.
 
  • #11
Sagittarius A said:
Say I'm someone without a clue, explain to me what gravity is and how it works.

Yes that's good way to put it. So what's the best guess at the moment what gravity is. Or is there real facts I've not yet found.

So example from good argument:
"The hypothesis is that the gravitational interaction is likewise mediated by a – yet undiscovered – elementary particle, dubbed the graviton, instead of being described in terms of curved spacetime as in general relativity."
http://en.wikipedia.org/wiki/Graviton

Again, like already mentioned, how can that interaction be from mass in black hole to outside, over event horizon.
 

Related to How Does Gravity Work and What Causes Time to Slow Down Near a Black Hole?

1. What is the theory of relativity?

The theory of relativity, developed by Albert Einstein, is a scientific theory that explains the relationship between space and time. It is divided into two parts: the special theory of relativity and the general theory of relativity. The special theory of relativity deals with objects moving at a constant velocity, while the general theory of relativity deals with objects in accelerated motion or in the presence of gravity.

2. How does the theory of relativity relate to time?

The theory of relativity states that time is not absolute, but rather it is relative and can be affected by factors such as motion and gravity. This means that the passage of time can be perceived differently by different observers depending on their relative motion and the strength of the gravitational field they are in.

3. What is time dilation?

Time dilation is a phenomenon predicted by the theory of relativity where time passes slower for objects that are moving at high speeds or are in strong gravitational fields. This means that someone moving at high speeds or near a massive object will experience time passing slower compared to someone who is stationary or in a weaker gravitational field.

4. Can time travel be possible according to the theory of relativity?

The theory of relativity allows for the possibility of time travel, but it is only theoretically possible and has not been proven to be achievable. According to the theory, time travel would require an object to move at speeds close to the speed of light, which is currently not possible with our current technology.

5. How does the theory of relativity impact our understanding of the universe?

The theory of relativity has greatly impacted our understanding of the universe by providing a new way of looking at space and time. It has helped us understand the effects of gravity on the movement of objects and has led to new discoveries in the field of astrophysics, such as black holes and gravitational waves. It has also been a fundamental part of many technological advancements, such as GPS systems and satellite communication.

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