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isthatmyex t1_j3welaz wrote

Reply to comment by d0ctorzaius in NASA satellite discovers second Earth-sized planet in habitable zone by Tuna_Sushi

If you rode a spaceship a light speed for 100 years. Wouldn't you age 100 years?

E: If you were then to look back at earth. It would appear as if nothing had changed at all.

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Arcanorum t1_j3wffr5 wrote

The faster you travel, the more time dilates. At the speed of light, time does not move at all.

From an outside observers perspective it would take 100 years. For anyone on the ship it would be instantaneous, if you assume no acceleration or deceleration period.

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Optimal-Grass-8989 t1_j3x2s0d wrote

So… how would you pilot the ship or address any issues that come up, like repairs?

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Arcanorum t1_j3x44eh wrote

In this scenario the ship is moving at the speed of light so it is not experiencing time, just like the people inside it.

It cannot breakdown while moving at lightspeed, because no time can pass to allow failures to occur.

But matter can't actually go the speed of light, only energy can, so this is all just a fun thought exercise.

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RonBourbondi t1_j3xfz95 wrote

So at 90% of the speed of light how does one do repairs?

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Arcanorum t1_j3xgw1b wrote

In theory, exactly the same as any other spaceship.

Anyone attempting repairs is operating in the same inertial reference as the ship, so from their perspective it's no different from repairing a ship at any other speed.

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RonBourbondi t1_j3xh9ad wrote

But by the time they make the repair couldn't they have arrived?

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Arcanorum t1_j3xhstn wrote

Yes. Depending on the strength of the time dilation, a repair may not be possible to complete before the journey is over.

But anyone capable of getting a ship near lightspeed would also have the physics and math knowledge necessary to calculate their level of time dilation, so they could make logical decisions regarding necessary repairs.

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Chronic_In_somnia t1_j3zm4rc wrote

The hard part comes when you want to stop lol

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Pineapple--Depressed t1_j406org wrote

My grandpa used to always say, "it ain't the fall that kills you, it's that sudden stop at the end that gets you..." Imagine how long it would take to safely decelerate from near lightspeed.

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Optimal-Grass-8989 t1_j3x78ph wrote

That’s a long to say you’re speculating 😂

Edit: yes, I’m specifically referring to your speculating on matter going the speed of light, and yes I’m still laughing.

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Arcanorum t1_j3x8v2i wrote

Time dilation as you approach the speed of light is not speculation, it's fact. Time slows down heavily the closer you approach lightspeed and does not pass at all for anything that can actually reach it.

Any discussion of matter going the speed of light is speculation, because it is impossible in our current understanding of physics.

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jschubart t1_j3xffn6 wrote

If you traveled at the speed of light, you would need to not have any mass. If you were to travel near the speed of light (e.g. 99.9% the speed of light), to you about 4.5 years would have passed. To everyone else, 100 years would have passed.

Here is a nice calculator:

https://www.omnicalculator.com/physics/time-dilation

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d0ctorzaius t1_j3wf17p wrote

At or near light speed, time dilation becomes a factor, so it would take 100 years to an observer but to the people in the ship, it would seem like a lot less time.

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isthatmyex t1_j3wfm1f wrote

But if you were on the ship, it would still be 100 years is my point.

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SomeInternetRando t1_j3winvj wrote

No, to you on the ship, you'd just teleport instantly. Or at slightly below the speed of light, it'd still be a lot quicker than 100 years.

>it would still be 100 years is my point

To an observer on earth. But not to you on the ship. If you had a telescope on a ship travelling towards earth near the speed of light, it may feel like a day to you (depending on speed), and if you looked at Earth through the telescope, it would look like Earth was going in fast-forward so fast that 100 years only takes one day.

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dagbiker t1_j3wvzng wrote

No, from your point of view it would be instant.

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