this post was submitted on 20 Jul 2023
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So I was day dreaming and I caught a thought. What if what we understand about physics is actually all there is to understand? What if you objectively cannot move faster than the speed of light because you can't do the time traveling things necessary. This would mean that the only way to travel amongst the stars would be to extend our lives so that a 5000 year trip at the speed of light would represent like 10% of our lifespans. Travel would be attainable but like the way it was when we were sailing ships to the new world.

That's just one practical solution I could think of to stellar travel. Does anyone else have a practical idea?

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[–] TauZero@mander.xyz 3 points 1 year ago (2 children)

You are behind the times on physics advancements buddy! Thanks to the recently discovered concept of relativistic time dilation, a 5000 light year trip at the speed of light will take literally 0 seconds of your lifespan. More practically, travelling in a starship that accelerates at 1G to the halfway point, turns around and decelerates to the destination, you can reach ridiculous distances within a single human lifetime:

shipboard time distance earth time
1 year .263 LY 1.05 Y
2 years 1.13 LY 2.37 Y
3 years 2.82 LY 4.35 Y
4 years 5.80 LY 7.50 Y
5 years 10.9 LY 12.7 Y
10 years 166 LY 168 Y
15 years 2199 LY 2201 Y
20 years 28.8 kLY 28.8 kY
25 years 380 kLY 380 kY
50 years 149 GLy 149 GY
100 years 22.8 ZLy 22.8 ZY

This is the formula to calculate the distance and time:

x(τ) = c**2/a [cosh(τ a/c) - 1]
t(τ) = c/a sinh(τ a/c)

a = 9.8 m/s
c = 3e8 m/s

The formula is hyperbolic, which is why travel distance is not a linear relation of travel time. E.g. given τ = 10 years:

x = 3e8**2/9.8 * (cosh(60*60*24*365*10/2 * 9.8/3e8) - 1) * 2 / (3e8 * 60*60*24*365)
  = 166 light years
t = 3e8/9.8 * sinh(60*60*24*365*10/2 * 9.8/3e8) * 2 / (60*60*24*365)
  = 168 years
[–] calhoon2005@aussie.zone 3 points 1 year ago (1 children)

But what about the bit about not hitting anything whilst travelling at that speed? Even a speck of space dust would do massive damage at those speeds, right?

[–] TauZero@mander.xyz 5 points 1 year ago

Oh yeah, it's like flying the wrong way down the tube of the Large Hadron Collider. The tougher challenge though is like @MuThyme@lemmy.world said maintaining 1G acceleration. Following the rocket equation, which is logarithmic, a 50 year multi-stage rocket will be bigger than the universe itself, even if you use some kind of nuclear propulsion 10000 times more efficient than our chemical rockets.

[–] danhab99@lemmy.world 0 points 1 year ago (2 children)

Wait so the only thing limiting our interstellar travel is money? That's awesome!!!

[–] Aux@lemmy.world 4 points 1 year ago

No, the only limit to everything in our lives and in the universe in general is... Energy! Energy is the real currency of the world.

[–] MuThyme@lemmy.world 1 points 1 year ago

Nah, it's actually super hard to maintain that acceleration. Not to mention all the fun of radiation, avoiding random obstacles and I assume the interstellar medium will become more dense to an accelerated observer.

We have idea on how to do it, but the engineering is far from it yet.

[–] A_A@lemmy.world 2 points 1 year ago (1 children)

Built a machine that can repair itself. Send it to a nearby planet. Give it the ability to manufacture human embryos from our genetic code using only inorganic material. Make at least 2 ; let's call them Adam and Eve. Keep this machine somewhere hidden and near them so to guide them and their offsprings for a few milleniums. Someday, if they are mature enough, tell them what happened.

[–] djc0@lemmy.world 2 points 1 year ago

I think most of us would like the possibility that WE can travel between the stars, not some incredibly disconnected OTHER.

For example, I would like to see Niagara Falls, not send someone there that I’ll never ever connect with again.

[–] polyfire@waveform.social 0 points 1 year ago (1 children)

It's kind of interesting to think of society like a videogame. Like we put our stats in oil and tech. But not much in biotech. The different style of civilisation advancement we are missing out on could be wild. But we can't go back and play the game from the start again, so we'll never see what that's like.

Could be computers built off of nerves instead of wires. Computers that grow and multiply. I wonder if it could lead to a new understanding of the nature around us and how we all fit and play a role in the galaxy.

Maybe our desire to explore space is immature. There may be whole other types of space that we can't see because we don't have the tech.

[–] Aux@lemmy.world 1 points 1 year ago

We already have a lot of biotech and even some biocomputers. The main issue is that bio structures are fragile for our common use cases.

We also have self replicating machines, 3D printers for example. They are as much as alive as viruses as both require some input from the hosts for full replication cycle. It's just that most people don't think about 3D printers as alive and self replicating beings.

[–] Kolanaki@yiffit.net 0 points 1 year ago (1 children)

I've wondered why no one seems to be seriously putting effort into a genealogical ship. I'd be okay with being the first generation; I can't possibly be the only one.

[–] perviouslyiner@lemm.ee 2 points 1 year ago

Where would you go, and what could one ship's crew do there?

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