Time & Gravity: How Much Slower on Earth?

In summary, the effect of gravity on time dilation is very small, but measurable. GPS satellites tick faster due to the lessened effect of gravity at their orbital distance, but even in a huge interstellar void, the difference would still be very small. It is impossible to determine the percentage difference in time on Earth compared to a place without gravity, as there is nowhere in the universe unaffected by gravity. It is also impossible to determine if time or space would exist without gravity or matter, as they are fundamental components of the universe.
  • #1
seb7
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Time slows down near gravity (or under acceleration);

so if a 100 seconds pass in space, somewhere wheres there is no (near zero) gravity, how many seconds passed on Earth over the period?

ie. what's the percentage difference does Earth experience against time that is not effected by gravity?
 
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  • #2
First, there is absolutely nowhere in the universe that is unaffected by gravity. Since the range of gravity is infinite, at best you can say that out there in a huge interstellar void the effect is very very small.

The effect of the Earth's gravity on time dilation is very small, but very measurable. The clocks on board GPS satellites tick at a rate of about 40 microseconds faster per day than a clock here on Earth thanks to the lessened effect of gravity at their orbital distance. Way off in an interstellar void there would be an even larger difference, but it would still be very small.

http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html
 
  • #3
hi seb7! :smile:
seb7 said:
Time slows down near gravity (or under acceleration);

no, time dilation does not depend on acceleration, only on speed (or gravity) :wink:
so if a 100 seconds pass in space, somewhere wheres there is no (near zero) gravity, how many seconds passed on Earth over the period?

ie. what's the percentage difference does Earth experience against time that is not effected by gravity?

time dilation due to gravity is approximately 1 - U = 1 - 2gM/rc2 = 1 - 2gr/c2 :smile:
 
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  • #4
Hi, yes I understand GPS satellites tick faster, but they are hardly out of the Earth's gravitational field.
So, what's the answer to 1 - U = 1 - 2gM/rc2 = 1 - 2gr/c2 ?
I'm interested to know what, as percentage, is time on Earth slowed, compared to a place without gravity.
 
  • #5
seb7 said:
I'm interested to know what, as percentage, is time on Earth slowed, compared to a place without gravity.

Drakkith said:
First, there is absolutely nowhere in the universe that is unaffected by gravity

There's your answer. (Or reason why there isn't an answer)
 
  • #6
In fact, we know that gravity in the early universe was 'denser' than it is in the present universe [re: the Permutter supernova study]. Gravitational time dilation is incredibly small near Earth due to its 'tiny' mass. In a gigantic, cosmological void, it is virtually negligible.
 
  • #7
So we have no idea of time without gravity? So that could mean time doesn't exist without gravity.
 
  • #8
seb7 said:
So we have no idea of time without gravity? So that could mean time doesn't exist without gravity.

Would space exist without gravity? Would either space or time exist without matter? There is no way to answer these questions because the universe has gravity, time, space, etc. What would happen if one didn't exist is unknowable since we do in fact have them.
 

1. How does gravity affect time on Earth?

Gravity has a significant effect on time on Earth. According to Einstein's theory of relativity, gravity bends the fabric of space-time, causing time to run slower in areas with stronger gravitational fields. Therefore, time runs slightly slower on Earth compared to areas with weaker gravitational fields.

2. Is time really slower on Earth compared to other places in the universe?

Yes, time is slower on Earth compared to other places in the universe. The difference, however, is very small and can only be measured with highly precise instruments. This is because the strength of gravity on Earth is relatively weak compared to other massive objects in the universe, such as black holes.

3. How much slower is time on Earth compared to space?

The difference in the speed of time on Earth compared to space is very small, on the order of nanoseconds. However, as objects with stronger gravitational fields, such as black holes, are approached, the difference in time becomes more significant.

4. Does the speed of time vary depending on altitude on Earth?

Yes, the speed of time does vary depending on altitude on Earth. This is because the strength of gravity is slightly weaker at higher altitudes, causing time to run slightly faster. This effect has been observed and measured in experiments using atomic clocks.

5. How does the rotation of the Earth affect the speed of time?

The rotation of the Earth also has a small effect on the speed of time. Objects at the equator, which are moving faster due to the Earth's rotation, experience time slightly slower compared to objects at the poles. This is known as time dilation and is also predicted by Einstein's theory of relativity.

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