Do You Age Slower In Space?

When you see that first grey hair or start noticing some small crows feet, you’ll do anything to slow down the aging process. Anti-wrinkle cream, healthy eating, exercise, these are all well and good. But what if there was a simpler option, like space travel? 

This isn’t as impossible as it seems, take astronaut Scott Kelly. Kelly has a twin brother called Mark who isn’t an astronaut. When Scott Kelly went into space, and Mark, who is slightly older than Scott stayed on earth, the age gap between them increased. Scott Kelly aged slower than his twin brother.

The brothers were born 6 seconds apart back in 1964 but when Scott Kelly returned from orbit, the gap had grown to a staggering 6 seconds and 5 milliseconds. Did Scott Kelly discover the key to eternal life, and if so, how did Scott Kelly age slower in space?

How To Age Slower In Space

The trick to aging slower in space is Einstein’s theory of relativity. What Einstein has theorized and what evidence has since confirmed, is that time is relative due to a fabric that permeates the whole universe called space-time, before the theory of relativity, space was seen as a sheet that housed the planets and stars, but now we’ve found that the planets, stars and anything with mass has as great as an effect on space as space does on us.

Space-time can be warped by matter or energy and rarely ever stays the same. This means that the rate time passes is changed and based on numerous different factors such as the weight of gravity or the speed at which you are moving. 

Time actually moves slower on earth than it does in space, this is because the earth’s gravitational force bends space-time in something that is called gravitational time dilation.

This means that if you were out in the middle of space, you would age faster than someone back home because the stronger the gravitational pull the slower time moves. As the gravitational pull is stronger the closer you are to the surface of the earth, shorter people actually age slower than taller people, however, this is by imperceptible fractions. 

But if the closer to the gravitational force means you age slower, then surely Scott Kelly should’ve aged faster than his twin brother Mark? This would be true if Scott was stationary the entire time, but it isn’t just gravity that affects the speed at which you age.

Time also moves slower the faster you are moving, this is called velocity time dilation. For the entire time Scott Kelly was in space he had been orbiting the earth at around 28,200 km/h, because of these tremendous speeds, the velocity time dilation has a bigger effect on Scott Kelly than Mark’s gravitational time dilation.

The effect of aging on people orbiting the earth in the ISS is very insignificant though, only a few milliseconds, but what if we could go further? Is there any way we could use this theory of relativity to time travel, to get the anti-aging method we’re looking for? For this, we’re going to have to look at the aptly named ‘Twin Scenario’.

The Twin Scenario

What if instead of Scott Kelly working in the orbit of the earth, he was shot off in a rocket going at a constant speed close to lightspeed and then turned around and came back while Mark was still on the earth? 

If Mark and Scott both synchronized their watches when Scott blasts off into space, and then we wait exactly 10 years until Scott comes back, then 10 years would’ve passed for Mark. However, with Scott, it would be a lot different, when Scott comes back he will be two years younger than his twin brother.

Why is this? Because Scott is traveling at tremendous speed, velocity time dilation would mean that time is moving slower for Scott while his spaceship is moving. Time will be moving in relation to Scott’s ship, Scott is only moving at lightspeed when he is going and coming back, there has to be a moment where he turns the rocket around, in this moment the rocket will not be moving at lightspeed.

That is where gravitational time dilation comes into play. When Scott is turning around, he will be stationary (or almost stationary) in space, meaning that time would be moving faster for Scott than it is for Mark who is closer to the gravitational pull of the earth. When Scott gets back he would’ve only been traveling for 8 years, whereas the stationary Mark had passed 10 whole years.

You don’t need a lightspeed rocket and a twin brother to prove this. Scientists have sent an atomic clock up in an airplane and it has come back with a different time on it than an atomic clock sitting stationary on the ground. Albeit a few milliseconds. 

Is Time Travel Possible?

It is very possible, and furthermore, it’s impossible not to travel in time. You cannot possibly go through life without changing the way you age. If you take frequent flights then you are time traveling, as you’ll be aging slower than you would if you were on the ground. If you decide to live in the penthouse of an apartment then you’re going to grow older than someone living in a basement. 

I do realize that these are all very minute changes to the way we perceive spacetime, but the twin scenario does show us that, in theory, time travel is very much a possibility.

If we were to go fast enough and far enough away then come back at the same speed then we could jump a few years into the future, of course, this would require transportation that can go very fast, lightspeed fast. Although it’s not the only way we could theoretically travel in time. 

As we know due to gravitational time dilation, the closer we are to an object with mass, the slower time will move to us in relation to the mass of that object.

If we can place ourselves close enough to an object with incredible mass, such as a black hole, theoretically time would move much slower for us, meaning that you could then leave the mass influence of the black hole and be in the future without aging as quickly as you would when you aren’t.

Of course, getting close enough to a black hole to be affected by its gravitational pull is going to be quite hard, but getting away from that gravitational pull is going to be much harder. 

Final Thoughts

You can age slower in space, but you won’t necessarily age slower just by being in space. In fact, you age way quicker in space due to gravitational time dilation, the only reason you can age slower in space is due to velocity time dilation.

When you are going at great speeds, time is relative to the speed that you are traveling, and because there is no gravity or air resistance in space, it is possible to travel a lot faster than if you were on earth.

Gordon Watts