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Relativistic Spaceship

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Re: Relativistic Spaceship

#241

Post by BoiledCabbage »

klyrs wrote: post #18

Yikes. At around 90%c, it's starting to look like a sunny day. Any physicists care to weigh in on the accuracy of this? I can search for the energy density of starlight in interstellar space... but how fast does one need to go to hit that "sunny day" point?

According to the simulation moving relativistically in addition to shifting the frequency also increases the intensity significantly. Something I had never heard about until now.

I'd love to find a reference for it as I found that surprising too.

Re: Relativistic Spaceship

#242

Post by dave333 »

Maybe if you could start by persuading a small black hole to go where you want and following in its wake (or lack of wake actually). The black hole swallows everything in your path and grows more powerful. Perhaps if you had an array of three or more black holes you could steer the group by differentially feeding them somehow. If the initial black hole were an orbiting pair your spaceship could orbit a lagrange point and be swept along.

Re: Relativistic Spaceship

#243

Post by BHSPitMonkey »

eru wrote: post #211
EA-3167 wrote: post #168

Earlier quoted context omitted.

It would be cheaper in every sense to turn something like a giant asteroid into a rotating habitat ship than achieve a constant 1g to even the closest systems. Realistically interstellar travel is not a thing that (biologically modern) humans will ever be suited for, robotic probes don't need thousands of kg of food and water to stay alive, don't need artificial gravity, air, or entertainment. The fact that the trip…

You are right. One addendum: many humans would be bothered by one-way trips, but humanity is large, and in absolute numbers there are still plenty of volunteers for one-way trips to the planets and stars.

And how many in that group are actually fit to spend many years living that lifestyle without losing their mind and getting into deadly fights with one another?

And who's covering the great expense of building these generational colony ships and training their only inhabitants, only to have them zip away never to be heard from again? (With no benefit other than believing there's a slight chance we've succeeded in making our species multi-plantary)?

Re: Relativistic Spaceship

#244

Post by Aachen »

It doesn't run in my browser and I want to thank the author for giving a proper error message! So often, pages just break for various reasons and you're just sitting there "is it gonna load?" or "is this what I'm supposed to be seeing?"

This is the first time I see "xyz is not supported", which both helps me understand what's wrong and lets me switch to a popular browser to see the content. And the site works and looks great there (on mobile)! Thanks OP :)

Re: Relativistic Spaceship

#245

Post by andrewflnr »

bee_rider wrote: post #49
m3kw9 wrote: post #14

Earlier quoted context omitted.

I wonder what is a safe acceleration to get to light speed for long periods without hurtin too much

You can’t “get to” light speed, that’s one of the big punchlines in relativity. If you pick an acceleration equal to the acceleration we experience on Earth (aka 1g, aka ~9.8m/s^2), you hit relativistic speeds (speeds at which you need to take into account the effects of relativity to do anything) surprisingly fast. On the order of hundreds of days. So, it is not really a matter of safe acceleration on a long space t…

> that’s one of the big punchlines in relativity

It's kind of funny that the actual big punchline is that light speed matters at all. There would be no meme of "reaching lightspeed" without relativity, despite that meme originating from relativity specifically mentioning lightspeed as something you can't reach.

Re: Relativistic Spaceship

#246

Post by cooper_ganglia »

JumpCrisscross wrote: post #160
cooper_ganglia wrote: post #129

Earlier quoted context omitted.

Well then, it's easy: Just always face the exhaust in that direction! It's not rocket science!

> always face the exhaust in that direction! It's not rocket science! You don't see a problem with trying to accelerate with two exhaust streams at 180º to each other?

In a universe where every action has an equal and opposite reaction, why not make those reactions argue about it?

Re: Relativistic Spaceship

#248

Post by wholinator2 »

hackerlight wrote: post #153
tshaddox wrote: post #130

Earlier quoted context omitted.

Do you mean that someone in the space ship could, without extending their own lifespan beyond what is already expected, use the space ship to "travel" to Earth's distant future?

Kip Thorne said it's theoretically possible. One end of the wormhole is on earth, the other is on the spaceship. Then you fly the spaceship and hop into the wormhole and arrive into the future on Earth.

You don't even need the wormhole. You just accelerate away to relativistic speeds then turn around and come back. It doesn't matter which direction you're going, just that you're going _fast_.

Re: Relativistic Spaceship

#249

Post by satvikpendem »

jcul wrote: post #86
robertlagrant wrote: post #43

Earlier quoted context omitted.

I like that old Arthur C Clarke novel, The Songs of Distant Earth[0], where they travel with an ablative shield in front made of ice, and they can make new shield segments by finding planets with water. [0] https://en.wikipedia.org/wiki/The_Songs_of_Distant_Earth

I read project hail Mary over Christmas, and they deal with this problem too. Though I can't say much without giving away spoilers. A great read if you are a sci-fi fan!

I recommend the audiobook in particular for this book.

Re: Relativistic Spaceship

#250

Post by satvikpendem »

e40 wrote: post #227
jcul wrote: post #86

Earlier quoted context omitted.

I read project hail Mary over Christmas, and they deal with this problem too. Though I can't say much without giving away spoilers. A great read if you are a sci-fi fan!

My second favorite sci-fi book of all time. Three body being the first.

Indeed. Have you read the rest of the series? It just gets crazier and crazier.
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