Gravity and time, am I understanding this?

In summary, the concept of relativity states that time appears to increase when in a stronger gravitational field. This is evident in events such as black holes and the Big Bang. In the case of a twin going to a neutron star, they would perceive time to move faster due to the stronger gravitational field, making them younger than their twin who stayed on Earth. However, from an outside perspective, time would appear to slow down for the twin in the gravitational field. This shows that differences in gravitational fields can affect the perception of time.
  • #1
Quanta-Man
[SOLVED] Gravity and time, am I understanding this?

I am pretty new to physics in general. From what I've gotten so far, relativity states that time increases (or the increments of time become more closely spaced) when gravitational field is stronger. This is illustrated in black holes and the Big Bang. In the earlier moments of the Big Bang, the gravitational field of the early universe would be much greater than it is now, therefore, time would go by at a much quicker rate in the early stages of expansion. Now, correct me if I am wrong, but say my twin goes to a neutron star (or something with a much greater gravitaional field than the earth) and stays for what he perceives to be 10 years. He then returns to Earth and meets up with me (who has stayed on Earth the entire time). In this case, wouldn't my twin be younger than I? So isn't this stating that the greater gravitational field on the neutron star caused time (to the twin) to slow down and thus the twin stays younger for a longer amount of time in relation to me, on earth? Is this a contradiction of stronger gravitational fields speeding time up? Shouldn't the twin age faster than I in this case?
 
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  • #2
It's a question of perspective, as are most things in relativity. To any person inside a strong gravitational field, time appears to "speed up". That is, the rest of the universe (outside the strong gravitational field) seems to go by quickly like a videotape on "fast forward".

However, if you were outside that gravitational field looking in at that person (your twin, for example), you would say that his time appears to "slow down". So your twin would indeed be younger than you, but you would dissagree as to the reason why. You would say that his time slowed down while he would say that your time sped up.
 
  • #3
Everyone sees their own timepiece proceeding normally. It's only in comparisons of different gravitational fields/velocities that differences are detected.

Time proceeds slower in a strong gravitational field as compared to a weaker gravitational field. So, it seems your premise is backwards and your twins example is correct.
 

1. How does gravity affect time?

Gravity affects time through a phenomenon called time dilation. This means that time moves slower in areas with stronger gravitational pull, such as near a massive object like a planet or star. This was famously proven through Einstein's theory of general relativity.

2. Can gravity alter the speed of time?

Yes, gravity can alter the speed of time. As mentioned before, time moves slower in areas with stronger gravitational pull. This means that time can appear to pass at different speeds for two observers in different gravitational fields.

3. How does time travel relate to gravity?

Time travel is a popular concept in science fiction, and it is often associated with the theory of general relativity and the effects of gravity on time. According to this theory, time travel could be possible by manipulating the effects of gravity through extremely strong gravitational fields or by traveling at high speeds.

4. Is gravity the only force that affects time?

No, gravity is not the only force that affects time. Other forces, such as velocity and acceleration, can also impact the passage of time. This is known as time dilation and is also a key principle in Einstein's theory of relativity.

5. How does the concept of spacetime relate to gravity and time?

The concept of spacetime is crucial in understanding the relationship between gravity and time. In Einstein's theory of general relativity, spacetime is a four-dimensional fabric that is affected by the presence of matter and energy. The curvature of this fabric, caused by the effects of gravity, is what causes time to move slower in areas with stronger gravitational pull.

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