ELi5 If time is slower at space, would you still age at the same rate as you would on earth?
In: Physics
From your perspective, yes. If you “experience” a year on the ship, you’ll be a year older.
However time is not an absolute quantity. While a “year” for you is always a year, your clock may be running slower or faster compared to a clock on earth: so while it may have been a year for you other people may have experienced for instance only four weeks. The result is that you are now eleven months older than your twin.
However time dilation really only becomes noticeable to humans at either extreme speeds or extreme gravity. For pretty much all human space adventures with modern technology the difference between a human that went in to space and a human that stayed behind is a few milliseconds at most.
In your own frame of reference, yes. Basically everbody sees their own clock ticking at one second per second. Relativity only comes in when you compare clocks moving relatively to each other or in different gravity.
If time passes slower for you (can be caused by being in a high gravity field or moving at incredible velocities) you will perceive time as moving the exact same, even if it is not. This is because your brain would also function slower as well. If time appears to have passed 10 years, you will age 10 years, but someone on Earth where time moves differently, they would age a different amount in that same amount of time.
For example, if John is in a rocket where time only moves at 20% that of time on Earth, John will age only 1/5 the amount of time. If 50 years passes on Earth, John would only perceive that as being 10 years that have passed and will only have aged 10 years as well.
It’s not really slower in space, it’s slower at high velocity. But effectively no, you would age slower compared to someone stationary, though at the speeds you are at in orbit the difference isn’t that much. You would need to move at pretty significant percentage of light speed before its effects became apparent.
In order to “slow” time by 15% you would have to travel like half the speed of light, which is about 95,000 miles per second. For comparison the fastest made made object peaked at like 60 miles per second. Typical satellites around Earth travel at about 5 miles per second.
Edit: its also probably worth noting this works on an exponential scale, so low speeds will not have much of an increase compared to those same changes in velocity at very high speeds.
Relativity is hard.
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