# Time dilation on the surface of the sun

1. Sep 18, 2015

### Andrew Wright

Hi,

I am wondering. Is it possible to predict the amount of time dilation on the surface of the sun compared to the surface of the earth? Is this a correct question to ask, or have I made a bad assumption?

Ayjay

2. Sep 18, 2015

### rootone

What is your frame of reference?
If you are standing on the surface of the Earth there is no time dilation locally, and if you could stand on the surface of the Sun there would be no time dilation locally there either.

Time dilation is what an observer in one frame sees happening to another object which is either travelling near light speed in relation to the observer, or otherwise it's in a very strong gravitational field which the observer is not in.

As seen from Earth and object on the surface of the Sun is in a relatively strong gravitational field, however I doubt that it's strong enough to cause a noticeable time dilation effect.
I'll leave it to the math gurus here to work out the exact figure but I'd guess it would be very small.

Last edited: Sep 18, 2015
3. Sep 18, 2015

### DEvens

Sure.

https://en.wikipedia.org/wiki/Gravitational_time_dilation

4. Sep 18, 2015

### Andrew Wright

So, what would the age difference be for say a twin on earth and a twin who spent their life (shielded) on the surface of the sun? Say they met up again after 70 years on earth?

5. Sep 18, 2015

### 15characters

6. Sep 18, 2015

### 15characters

To illustrate then, without accounting for the effects of rotation, proximity to the Earth's gravitational well will cause a clock on the planet's surface to accumulate around 0.0219 fewer seconds over a period of one year than would a distant observer's clock. In comparison, a clock on the surface of the sun will accumulate around 66.4 fewer seconds in one year.https://en.wikipedia.org/wiki/Gravitational_time_dilation

7. Sep 18, 2015

### Andrew Wright

thanks :)

8. Sep 18, 2015

### Staff: Mentor

There's nothing wrong with 15Characters's reply, but OP should be aware that the rotational effects are also noticeable at the scale that we're working with here.

9. Sep 19, 2015

### Janus

Staff Emeritus
For example, for that far off observer, Earth's position in the Sun's gravitational field and orbital speed alone accounts for ~0.469 sec over a year.