Time Dilation: 1 Hour=77 Hours - Can I Phone?

Click For Summary

Discussion Overview

The discussion revolves around the implications of time dilation near a supermassive black hole, specifically addressing a scenario where one participant experiences 1 hour while 77 hours pass on Earth. The inquiry focuses on the nature of communication between the two, questioning whether this situation presents a paradox.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant poses a scenario involving time dilation and asks if communicating with someone on Earth during this time presents a paradox.
  • Another participant confirms the time dilation ratio, stating that 1 hour for the person near the black hole equates to 77 hours on Earth.
  • Several participants argue that this situation does not constitute a paradox, with one suggesting that the communication would result in the Earth-based person hearing the other speaking rapidly, while the person near the black hole would hear the Earth-based person speaking slowly.
  • Another participant adds that the voice would be redshifted, further complicating the communication, as it would sound much slower and deeper due to the time dilation effects.
  • There is a correction regarding the asymmetry of the situation, with one participant clarifying that the father, being farther from the black hole, experiences time at a different rate than the son, leading to a misunderstanding of who perceives the other as slowed down or sped up.
  • A participant acknowledges a mix-up regarding the positions of the individuals involved in the scenario.
  • A light-hearted reference is made to a childhood memory of seeing a sped-up video, possibly as an analogy to the discussion on time perception.

Areas of Agreement / Disagreement

Participants generally agree that the scenario does not present a paradox, but there is disagreement regarding the specifics of how each party perceives the other's speech due to time dilation. The discussion remains unresolved in terms of the precise nature of the communication effects.

Contextual Notes

There are unresolved assumptions regarding the nature of gravitational time dilation and the effects on communication, as well as the potential complexities introduced by redshift and the perception of time by each party.

Mitchell Swan
Messages
1
Reaction score
0
I was talking to my dad not long ago and he asked me an extremely valid question, so basically, the question is.
If I'm next to a supermassive black hole, and 1 hour for me is 77 hours on earth, and my dad rings me, bearing in mind you would an extremely good signal, but let's just say i answered, and we spoke for an hour(my time)he would of been speaking for 77 hours back on earth?
Please can someone give me an answer? (Is this a paradox)
 
Physics news on Phys.org
That is exactly what "and 1 hour for me is 77 hours on earth" means, yes.
 
  • Like
Likes   Reactions: Mitchell Swan
No, that is not a paradox. He would hear you talking very rapidly, you would hear him talking very slowly. (At a ratio of 77 hours to one hour, it would probably be very difficult for either of you to understand the other!)
 
Also, I expect what you say will be redshifted by that same factor, he will hear you speaking very very slowly in a truly deep voice - like playing a recording 77x slower than it was recorded.
 
  • Like
Likes   Reactions: Mitchell Swan
HallsofIvy said:
No, that is not a paradox. He would hear you talking very rapidly, you would hear him talking very slowly. (At a ratio of 77 hours to one hour, it would probably be very difficult for either of you to understand the other!)
no his dad will hear him talking very slowly.
 
Prashan Shan said:
no his dad will hear him talking very slowly.
No, HallsOfIvy is correct. This is gravitational time dilation. It is not symmetrical like that.
 
DaleSpam said:
HallsOfIvy is correct. This is gravitational time dilation. It is not symmetrical like that.

But his dad is the one who is distant from the hole, and whose clock is therefore running faster. So dad will see son greatly slowed down, and son will see dad greatly speeded up. There is indeed an asymmetry, but HallsOfIvy had its direction wrong.
 
Oops! I was getting who was where mixed up too. My apologies Prashan.
 
I recall seeing Peter Ustinov sped up on TV as a kid.
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 65 ·
3
Replies
65
Views
13K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 61 ·
3
Replies
61
Views
5K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 18 ·
Replies
18
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 14 ·
Replies
14
Views
3K