You’d get to all your appointments really early.

Impossible. I wouldn't leave until after they started if I were moving at the light speed.

There was a young lady named Bright

Whose speed was far faster than light;

She set out one day

In a relative way

And returned on the previous night.

There would be time dilation. So time for you would be slower than it is for us which means when you come back from your trip depending on how far you went at that speed hundreds of years could pass on Earth

This is basic special relativity (time dilation), and there's a lot of literature on it. You'd experience time normally, but objects outside of your reference frame would experience time faster at a factor of "gamma".

Thank you! I was watching something about different times on planets and it just got me thinking that if your moving at a speed that fast. There has to be some sort of time change between each.

So in retrospect.. Time travel into the future?

Anyways, Would you feel the difference at all? Say you spend the 3 or so day to go to the ISS. Then turn back around and take another 3 days. Six days total in space. When you get back it's been six days to you. It's been twelve days to everyone else.

Not twelve days, but slightly longer than six. But yes, time travel into the future; however we are already doing that at the rate of one second per second. The faster you go, the more that rate increases. Moving to the ISS in three days does not get you anywhere near the speed of light, so this effect is negligible and I'd argue that general relativity time dilation would be a greater effect.

Gamma is 1/sqrt(1-(v^2 /c^2 )) so unless you are travelling near the speed of light, special relativity is extremely minor. If your velocity was great enough for gamma to equal 2, you would experience half the time as a stationary observer would. It's all weird stuff.

Definitely got me now lol. I guess I was just tossing examples of times more so then knowing.

So how do people achieve getting close to the spped of light? I know how an engine runs. Fuel, spark, and air. But does that go the same for rockets?

Last question for now lol, so from what I gather is person 1 (going the speed of light) and person 2 (sitting at home) P2 would have a longer time then P1 would technically have even though it's technically the same time plane?

If you travelled at the speed of light, your relative time reduces to zero; this means, whatever the distance you travel, the journey is instantaneous. Firsty, Its impossible to travel that fast because your mass increases all the way to infinity at the speed of light. Light itself (photon) is massless so it can do this. From a very early age, Einstein thought about what would it be like to travel on the back of a photon, and this is what he eventually discovered. A photon of light travelling from a star 100,000 light years away takes 100,000 years to hit your eye, from your perspective. But from the photons perspective, the journey was instantaneous.

>So how do people achieve getting close to the spped of light?

We don't. The amount of energy required to accelerate a mass is proportional to gamma, as the relativistic mass increases.

>technically the same time plane?

This is a nonsensical statement.

Keep reading, and stay away from youtube. Einstein's book is readily available. I'll buy it for you if you DM me and you cannot afford it.

To others it would look like you would not age at all. Time has no value or direction in lightspeed for the observers..

>So in retrospect.. Time travel into the future?

Yep, astronauts do it all the time, although not by very much, obviously!

You can't go the speed of light... Problem solved.

Let's say you took a trip to Alpha Centauri, about 4 light years away, going 90% the speed of light all the way there and back (we'll pretend you don't need to accelerate and decelerate). To observers on Earth, about 8.8 years would have passed before you return. However, from your perspective, only about 3.8 years would have passed. Your biological age would have increased by 5 years less than everybody else, though each person would feel as though time had passed normally for them.

Edit: as a side note, if you could travel at 99.9999% the speed of light, you could get to the center of the Milky Way galaxy and back within a typical human lifetime. Of course, back on Earth more than 50,000 years would have passed and humanity might not be here anymore.

BTW, here is a handy calculator to figure out how the passage of time changes as you approach the speed of light relative to other reference frames.

https://www.omnicalculator.com/physics/time-dilation#:~:text=How%20to%20calculate%20time%20dilation,measured%20by%20the%20moving%20observer.

For yourself? No change.

Rest of the world is a different matter.

Time would slow down the closer you get towards light speed. However. Albert Einstein said that even if you had a ship capable of that. That the width of your ship would expand endlessly. And the lenght of your ship would decrease endlessly. Basically meaning it isnt possible to go the speed of light because neither you or your ship would survive that.

They have done tests with atomic clocks. Which were perfectly in sync with one another. One of them they left on the ground. The other they put on one of the fastest jets they had. And noticed that time does indeed slow down. The difference was so small that it barely made a difference. But it proved Albert Einsteins theory.

So here’s something we all have experienced that demonstrates this but had no idea. Next time your flying in an airliner, look out the window. While you and the people on the ground experience time about the same, it’s actually passing slower for you than them. Now this difference is minuscule but its there. But as your flying, try to find a group of cars on the interstate or highway below you. To you, they look like they are hardly moving and to them your moving quickly. Time as the speed of light is like that.

At the speed of light, it doesn't. Seriously, time ceases to pass for anything travelling at C.

For anything moving through spacetime, the passage of time is slowed. The magnitude of this slowing (the "time dilation factor") increases as velocity as a fraction of C increases. Yes; this means that right now you are technically experiencing Special-Relativistic time dilation because of Earth's motion through spacetime (and have been for your entire life, so it's all you know).

This is not a linear relationship; the time dilation factor is very small until you achieve a significant fraction of C. It doesn't reach 2 (so time is passing at 1/2 the base rate) until something like 0.85C. As your velocity approaches C, the time dilation factor tends to infinity (and the passage of time slows to an arbitrarily slow rate).

Technically speaking, nothing with mass can travel through spacetime at C, only at arbitrarily-high fractions of C (which also takes inconceivable quantities of energy, but that's a separate discussion entirely). The key words there are "through spacetime", though. If you can find a way to bypass spacetime or modify it in some way so that you can cover a longer distance faster without actually going faster *through* that spacetime, then you can avoid the Special Relativistic effects. That includes the time dilation *and* the prohibitive energy costs.

For perspective on what that all *means*:

If you were to travel to the Centauri system (~4 ly away) at a velocity of 0.85C, the trip would take just over 4.7 years. Because of the time dilation (which is actually 1.7, not quite 2), it would seem from your perspective that the trip took a bit over 2.76 years.

In order to preserve the speed of light in your own local reference frame, it would also appear from your perspective that the spacetime you passed by was compressed by the exact same amount as the time dilation factor (so it would seem like you had only traversed ~2.35 ly in that 2.75 years, giving a velocity of 0.85C).

There's a great Cosmos episode (original series) about this!