What if solving interstellar travel isn't about figuring out faster than light propulsion, but how to extend our own lives?

TauZero , 11 months ago

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 timedistanceearth time1 year.263 LY1.05 Y2 years1.13 LY2.37 Y3 years2.82 LY4.35 Y4 years5.80 LY7.50 Y5 years10.9 LY12.7 Y10 years166 LY168 Y15 years2199 LY2201 Y20 years28.8 kLY28.8 kY25 years380 kLY380 kY50 years149 GLy149 GY100 years22.8 ZLy22.8 ZYThis is the formula to calculate the distance and time:

<pre style="background-color:#ffffff;">
<span style="color:#323232;">x(τ) = c**2/a [cosh(τ a/c) - 1]
</span><span style="color:#323232;">t(τ) = c/a sinh(τ a/c)
</span><span style="color:#323232;">
</span><span style="color:#323232;">a = 9.8 m/s
</span><span style="color:#323232;">c = 3e8 m/s
</span>

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

<pre style="background-color:#ffffff;">
<span style="color:#323232;">x = 3e8**2/9.8 * (cosh(60*60*24*365*10/2 * 9.8/3e8) - 1) * 2 / (3e8 * 60*60*24*365)
</span><span style="color:#323232;">  = 166 light years
</span><span style="color:#323232;">t = 3e8/9.8 * sinh(60*60*24*365*10/2 * 9.8/3e8) * 2 / (60*60*24*365)
</span><span style="color:#323232;">  = 168 years
</span>

danhab99 OP , 11 months ago

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

spacedancer , 11 months ago

That, and figuring out how to travel even just a significant fraction of the speed of light.

MuThyme , 11 months 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.

Aux , 11 months 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.

calhoon2005 , 11 months ago

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 , 11 months 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 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.