# Earth time dilation vs Sun time dilation

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• orion1977
In summary, the video says that on Earth, 24 hours pass in 86,400 seconds, but on the sun, 86,400.2 seconds pass. If time passes slower with more massed objects, then a twin on the Sun would be younger than a twin on Earth. However, the video does not say that more time has elapsed on the Sun.
orion1977
In the MinutePhysics video "How long is a day in the Sun?" it is said 24 hours on Earth is 86,400.0 seconds, but on the Sun 86,400.2 seconds would pass.

However, if time passes slower with more massed objects, then wouldn't a twin on the Sun be younger than a twin on the Earth? If so, is the video wrong in saying more time has elapsed on the Sun?

orion1977 said:
In the MinutePhysics video "How long is a day in the Sun?" it is said 24 hours on Earth is 86,400.0 seconds, but on the Sun 86,400.2 seconds would pass.

However, if time passes slower with more massed objects, then wouldn't a twin on the Sun be younger than a twin on the Earth? If so, is the video wrong in saying more time has elapsed on the Sun?

I suppose they mean 86,400.2 earth-seconds would pass while you measure only 86,400 seconds on the sun. So time would flow slightly slower, and the Earth twin would age more (by .2 seconds per day).

orion1977 said:
However, if time passes slower with more massed objects, then wouldn't a twin on the Sun be younger than a twin on the Earth? If so, is the video wrong in saying more time has elapsed on the Sun?
Natural language isn't well adapted for describing things like this unambiguously. As @Gan_HOPE326 says, if you put a clock on the surface of the Sun and sat on Earth with a powerful telescope watching that clock, it would not show that 86,400s had elapsed until slightly more had passed on your own clock. The Sun-based clock would always have a lower (and getting farther behind) reading than your clock - so it would be younger than yours by an increasing margin.

I haven't checked their numbers.

Last edited:
Ibix said:
Natural language isn't well adapted for describing things like this unambiguously.

(slight aside: it's funny I should read this remark today as I've just started reading the story from which the movie "Arrival" is adapted and

it dwells a lot on how different the language as well as the physics of an alien race with an a-temporal perspective is. For example they find extremely natural and fundamental the concept of "action" while they need to derive quantities such as velocity. Similar considerations I assume would apply to someone who developed in a context in which relativistic effects are daily occurrences.

)

## 1. What is time dilation?

Time dilation is a phenomenon in which time appears to move slower or faster depending on the observer's frame of reference and relative speed. It is a prediction of Einstein's theory of relativity and occurs when an object is moving at speeds close to the speed of light or in the presence of a strong gravitational field.

## 2. What is Earth time dilation?

Earth time dilation refers to the slowing down of time on Earth due to its rotation and orbit around the sun. This effect is relatively small and can only be observed with precise measurements. It is also affected by factors such as altitude and velocity.

## 3. What is Sun time dilation?

Sun time dilation, also known as gravitational time dilation, is the slowing down of time in the presence of a massive object such as the sun. This effect is much greater than Earth time dilation due to the sun's strong gravitational field. It has been confirmed through experiments such as the Pound-Rebka-Snider experiment.

## 4. How does Earth time dilation compare to Sun time dilation?

Earth time dilation is significantly smaller than Sun time dilation. For example, at sea level, time on Earth runs about 0.000000001 seconds slower per second compared to a clock in space. In contrast, time near the surface of the sun runs about 66,600 times slower per second compared to a clock in space.

## 5. Is it possible to experience time dilation on Earth?

Yes, it is possible to experience time dilation on Earth, but the effect is minuscule and can only be detected with precise measurements. For example, astronauts in orbit around Earth experience a slightly slower passage of time compared to people on the surface due to their higher velocity. However, for everyday human experiences, the effects of time dilation are negligible.

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