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

• Mitchell Swan
In summary, the conversation revolved around the question of what would happen if someone near a supermassive black hole had a conversation with someone on Earth. It was explained that due to gravitational time dilation, one hour for the person near the black hole would be equivalent to 77 hours on Earth. This would result in the two individuals hearing each other at different speeds, making it difficult to understand each other. However, it was clarified that this is not a paradox and the asymmetry in time dilation would depend on the distance from the black hole.
Mitchell Swan
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?

That is exactly what "and 1 hour for me is 77 hours on earth" means, yes.

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.

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.

## 1. What is time dilation?

Time dilation is a phenomenon predicted by Einstein's theory of relativity where the passage of time is observed differently by two observers in relative motion. It states that time appears to slow down for objects in motion compared to those at rest.

## 2. How does time dilation occur?

Time dilation occurs due to the fact that the speed of light is constant for all observers, regardless of their relative motion. This means that as an object's speed increases, time appears to slow down for that object to maintain the speed of light.

## 3. What is the relationship between time dilation and gravity?

Time dilation also occurs in the presence of strong gravitational fields. This is known as gravitational time dilation and is a result of space and time being curved by massive objects, causing time to pass at different rates depending on the strength of the gravitational field.

## 4. What is the significance of "1 Hour = 77 Hours" in time dilation?

This statement is an example of time dilation where an object traveling at a speed close to the speed of light would experience time passing at a rate 77 times slower than an observer at rest. This means that for every 1 hour that passes for the observer at rest, 77 hours would pass for the object in motion.

## 5. Can time dilation be observed in everyday life?

Yes, time dilation has been observed in everyday life through experiments and technologies such as atomic clocks on airplanes and satellites, which have been shown to experience time dilation due to their high speeds. However, the effects are very small and can only be observed in extreme conditions such as near the speed of light or in strong gravitational fields.

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