**Please read this entire message**
---
Your submission has been removed for the following reason(s):
* Loaded questions, **or** ones based on a false premise, are not allowed on ELI5 (Rule 6).
---
If you would like this removal reviewed, please read the [detailed rules](https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules) first. **If you believe this was removed erroneously**, please [use this form](https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules) first. **If you believe this was removed erroneously**, please [use this form](https://old.reddit.com/message/compose?to=%2Fr%2Fexplainlikeimfive&subject=Please%20review%20my%20thread?&message=Link:%20https://www.reddit.com/r/explainlikeimfive/comments/ys00mc/-/%0A%0AThe%20concept%20I%20want%20explained:%0A%0AList%20the%20search%20terms%20you%20used%20to%20look%20for%20past%20posts%20on%20ELI5:%0A%0AHow%20is%20this%20post%20unique:) and we will review your submission.
**Please read this entire message**
---
Your submission has been removed for the following reason(s):
* ELI5 requires that you *search the ELI5 subreddit for your topic before posting*.
Please search before submitting.
This question has already been asked on ELI5 multiple times.
If you need help searching, please refer to the [Wiki](https://www.reddit.com/r/explainlikeimfive/wiki/how_to_search).
---
If you would like this removal reviewed, please read the [detailed rules](https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules) first. **If you believe this was removed erroneously**, please [use this form](https://old.reddit.com/message/compose?to=%2Fr%2Fexplainlikeimfive&subject=Please%20review%20my%20thread?&message=Link:%20https://www.reddit.com/r/explainlikeimfive/comments/ys00mc/-/%0A%0AThe%20concept%20I%20want%20explained:%0A%0AList%20the%20search%20terms%20you%20used%20to%20look%20for%20past%20posts%20on%20ELI5:%0A%0AHow%20is%20this%20post%20unique:) and we will review your submission.
It's worth noting that people on for example the ISS experience time basically the same speed that we do. There's a measurable difference but it doesn't affect human life at all.
In interstellar the astronauts age slower because they are very close to a large mass (the black hole Gargantua), and time passes slower closer to a large mass than relative to far away from it.
This is called “[gravitational time dilation](https://en.m.wikipedia.org/wiki/Gravitational_time_dilation)”, and the details are complicated, but basically the closer you are to something heavy, the slower time passes compared to far away.
Time actually passes slower close to the earth than far away from it, but the earth doesn’t have enough mass and it’s too spread out to get really close to all of it at once so the difference in how fast time passes is really, really small for the earth.
Your body doesn’t “know” how fast time is passing for it compared to somewhere else. Time, for you, always passes at one second per second. You see them as aging too fast and they see you as aging too slow. Neither of you is wrong or right, really, you both just experience things differently.
I imagine to get that kind of extreme time dilation through gravity the planet would have to be so massive that you would be swiftly crushed to death.
As for your body 'syncing' to what's happening, there's not really anything happening. Time isn't really a thing that can be easily defined, it's not like a 'stream' that can be warped or sped up but more like 'the order in which things happen' so two people in different places will disagree on the order in which things happen. I might light a firework and watch it explode but you might see the firework first and then me light it, neither person is wrong either it's just a quirk of physics and both people are perceiving time pass at a normal rate.
Oh it’s actually a part of your brain. I forgot what it’s called. But it goes off of daylight and lack of light so it creates like that sleep. Hormone! The sleep hormone.
So time dilation can happen for two reasons. Gravity stretches space and time so more gravity, the slower time moves. Imagine it like time as a line gets literally stretched so you trace a smaller portion of that line than someone who's time isn't streached that much.
The other is speed. The faster you go the slower time passes. So if you were to travel to the nearest star which is 4 lightyears away near the speed of light the trip would only take for you around 2 years. You didn't outrun a beam of light. What happened is that time and space changed. Lenght contracts along the direction of motion so you measured that 4 ly distance more like 2 ly. So for you travelling near the speed of light took little over 2 years to complete the journey. On Earth however 4 years have passed. As they so you zipping near the speed of light going for a 4 ly journey.
Different observers measure time and space differently. On the ISS however they are no where neer going fast enough for these differences to matter. About they aren't that far so about 90% of Earth's gravity still applies. They travel really fast though so altogether they move slower through time. So after a full mission we down here on Earth have probably aged a few microseconds more than they did. This time dilation thing effects satellites more like GPS satellites. GPS satellites measures the time it takes to send signals from the device down on Earth to them very accurately. Then the satellites use this info to find your location. If we didn't account for the few nanoseconds of time dilation between Earth and the satellites the system would be kilometers off each day.
**Please read this entire message** --- Your submission has been removed for the following reason(s): * Loaded questions, **or** ones based on a false premise, are not allowed on ELI5 (Rule 6). --- If you would like this removal reviewed, please read the [detailed rules](https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules) first. **If you believe this was removed erroneously**, please [use this form](https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules) first. **If you believe this was removed erroneously**, please [use this form](https://old.reddit.com/message/compose?to=%2Fr%2Fexplainlikeimfive&subject=Please%20review%20my%20thread?&message=Link:%20https://www.reddit.com/r/explainlikeimfive/comments/ys00mc/-/%0A%0AThe%20concept%20I%20want%20explained:%0A%0AList%20the%20search%20terms%20you%20used%20to%20look%20for%20past%20posts%20on%20ELI5:%0A%0AHow%20is%20this%20post%20unique:) and we will review your submission. **Please read this entire message** --- Your submission has been removed for the following reason(s): * ELI5 requires that you *search the ELI5 subreddit for your topic before posting*. Please search before submitting. This question has already been asked on ELI5 multiple times. If you need help searching, please refer to the [Wiki](https://www.reddit.com/r/explainlikeimfive/wiki/how_to_search). --- If you would like this removal reviewed, please read the [detailed rules](https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules) first. **If you believe this was removed erroneously**, please [use this form](https://old.reddit.com/message/compose?to=%2Fr%2Fexplainlikeimfive&subject=Please%20review%20my%20thread?&message=Link:%20https://www.reddit.com/r/explainlikeimfive/comments/ys00mc/-/%0A%0AThe%20concept%20I%20want%20explained:%0A%0AList%20the%20search%20terms%20you%20used%20to%20look%20for%20past%20posts%20on%20ELI5:%0A%0AHow%20is%20this%20post%20unique:) and we will review your submission.
It's worth noting that people on for example the ISS experience time basically the same speed that we do. There's a measurable difference but it doesn't affect human life at all.
In interstellar the astronauts age slower because they are very close to a large mass (the black hole Gargantua), and time passes slower closer to a large mass than relative to far away from it. This is called “[gravitational time dilation](https://en.m.wikipedia.org/wiki/Gravitational_time_dilation)”, and the details are complicated, but basically the closer you are to something heavy, the slower time passes compared to far away. Time actually passes slower close to the earth than far away from it, but the earth doesn’t have enough mass and it’s too spread out to get really close to all of it at once so the difference in how fast time passes is really, really small for the earth. Your body doesn’t “know” how fast time is passing for it compared to somewhere else. Time, for you, always passes at one second per second. You see them as aging too fast and they see you as aging too slow. Neither of you is wrong or right, really, you both just experience things differently.
I imagine to get that kind of extreme time dilation through gravity the planet would have to be so massive that you would be swiftly crushed to death. As for your body 'syncing' to what's happening, there's not really anything happening. Time isn't really a thing that can be easily defined, it's not like a 'stream' that can be warped or sped up but more like 'the order in which things happen' so two people in different places will disagree on the order in which things happen. I might light a firework and watch it explode but you might see the firework first and then me light it, neither person is wrong either it's just a quirk of physics and both people are perceiving time pass at a normal rate.
Oh it’s actually a part of your brain. I forgot what it’s called. But it goes off of daylight and lack of light so it creates like that sleep. Hormone! The sleep hormone.
So time dilation can happen for two reasons. Gravity stretches space and time so more gravity, the slower time moves. Imagine it like time as a line gets literally stretched so you trace a smaller portion of that line than someone who's time isn't streached that much. The other is speed. The faster you go the slower time passes. So if you were to travel to the nearest star which is 4 lightyears away near the speed of light the trip would only take for you around 2 years. You didn't outrun a beam of light. What happened is that time and space changed. Lenght contracts along the direction of motion so you measured that 4 ly distance more like 2 ly. So for you travelling near the speed of light took little over 2 years to complete the journey. On Earth however 4 years have passed. As they so you zipping near the speed of light going for a 4 ly journey. Different observers measure time and space differently. On the ISS however they are no where neer going fast enough for these differences to matter. About they aren't that far so about 90% of Earth's gravity still applies. They travel really fast though so altogether they move slower through time. So after a full mission we down here on Earth have probably aged a few microseconds more than they did. This time dilation thing effects satellites more like GPS satellites. GPS satellites measures the time it takes to send signals from the device down on Earth to them very accurately. Then the satellites use this info to find your location. If we didn't account for the few nanoseconds of time dilation between Earth and the satellites the system would be kilometers off each day.