Why does time stop in the event horizon of a blackhole?

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Time appears to slow down at the event horizon of a black hole due to the effects of gravitational time dilation, as described by General Relativity. An object falling into a black hole experiences no change in its own perception of time, while a distant observer sees it slow down and never fully enter the black hole. This phenomenon is linked to gravitational redshift, where light emitted from a strong gravitational field appears redder due to the slower clock rates at lower gravitational potentials. The discussion emphasizes that both gravitational time dilation and redshift are real effects, supported by experimental observations involving light signals between different gravitational fields. Understanding these concepts requires a grasp of the underlying mathematics, as highlighted by educational resources like Leonard Susskind's lectures.
Manraj singh
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Why does time stop in the event horizon of a black hole? Or at least slow down, from what i know.
 
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It depends on the reference frame. Something falling in experiences no effect on time. However a distant observer would see the object as slowing down and never quite falling in.

The explnation is in the equations of General Relativity. (I am no expert).
 
leonard susskind describes it pretty good on youtube classic mechanics lectures from stanford university really learned a lot from his lecture heavy into math if you ask me but he says it elementary math
 
Mr Marcus, the link given by you helped a lot. Please correct me if I am wrong: time does not actually decrease, but it appears to be slowed down due to red shift or blue shift.Sent from my iPad using Physics Forums
 
Manraj singh said:
Mr Marcus, the link given by you helped a lot. Please correct me if I am wrong: time does not actually decrease, but it appears to be slowed down due to red shift or blue shift.Sent from my iPad using Physics Forums

Time dilation really does occur, it's not just a result of red shift.
 
Manraj singh said:
Mr Marcus, the link given by you helped a lot. Please correct me if I am wrong: time does not actually decrease, but it appears to be slowed down due to red shift or blue shift.
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I think people can have different perspectives on appearance vs. reality, Manraj.

Personally I consider gravitational time dilation to be absolutely real! And I consider it to be the same phenomenon as gravitational redshift.

Deeper down clocks run slower, the evolution of physical states is slower, the atoms in the downstairs laser vibrate slower, so the light it makes is redder---all from the standpoint of the guy upstairs.

The gravitational time dilation is what CAUSES the gravitational redshift. So both are actually real. That is just how I see it. Other people may have different ways to understand it.

I can see no other explanation for the gravitational redshift. Can you?

I think the way they experimentally TEST these gravitational effects is by sending light (or other electromagnetic signals) back and forth between "upstairs" and "downstairs" atomic clocks and other devices.
 
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