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johndburger t1_iw4t10y wrote

Reply to comment by Siellus in Will mankind ever travel outside our solar system? by savol_

We don’t need “insanely fast” speeds. We just need a technology that produces a constant thrust. Proxima Centauri is less than four years away (ship time) at one gravity.

Edit to remove first sentence. 1G of thrust will eventually get you to insanely fast speeds of course.

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Siellus t1_iw4ut4h wrote

Proxima Centauri is 4.2 light years away - There's no possible way your math checks out. You would need to be travelling at Light speed the entire length of the trip to get there within 4 years, You're also completely neglecting time required to slow down, which would be significant.

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hardervalue t1_iw59vy5 wrote

1G of thrust is impossible to maintain for long without millions of times more energy than humans have ever generated during the entirety of human history. The most dense amount of energy possible is antimatter, which we've only created nano-grams of at a cost that would extrapolate to $67 trillion per gram.

And if the math on this page is correct,

https://www.desy.de/user/projects/Physics/Relativity/SR/rocket.html

for every ton of ship & payload you want to send to Proxima Centauri you need 10 tons of antimatter to get there and 37 tons to actually slow down to visit instead of flying right by. The reason for the difference is the tyranny of the rocket equation, which means every ton of fuel you add to try to go faster increases the amount of fuel you need to get to the same speed because you also have to accelerate that additional fuel And that assumes 100% perfect engine efficiency, which is unlikely.

In reality solar sails driven by huge lasers is going to be an important part of travel to nearby stars because it avoids the tyranny of the rocket equation.

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Evening_Team t1_iw5gyiu wrote

So that entails, to make a mission to an exoplanet that's more than making flyby measurements, a deconstructed (on Earth) and self-reconstructing exploration entity must be beamed to that exoplanet in many millions of pieces. Solar sail-transported pan-technospermia. So be it .. that is, if the road map for making something more robust definitely indicates that many further decades of development are required.

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