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0 pointstunesmith6y ago0 comments

No, it assumes you start and end at whatever that maximum velocity is that we've been able to achieve.

That'd be fun to add, though. I'm not really sure what human-safe acceleration is - people here assume it's in the 1g-3g range. (That seems like a lot to me though, particularly for a long period of time - I think anything more than a fraction of g would be wildly uncomfortable.)

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7 comments · 2 top-level

healsjnr16y ago· 3 in thread

1G would be great as it would remove any unexpected physiological impacts of living in zero or low gravity.

Having said that, the distance and duration means that only a small portion of this journey would be under acceleration, the rest would be in zero g.

Spending a century in zero g would probably have a bunch of strange side effects and almost certainly mean that the people alive when they arrived wouldn't be able to stand the planets gravity.

This exact topic is what about 80% of The Expanse is about.

bestest6y ago

Not quite true. You'd spend half of the travel time under 1g accelerating, then the ship does a 180 degree flip in 0g, and then you spend another half of the travel time under 1g decelerating.

Edit: Of course, at constant 1g acceleration, at day number 354 we reach 1c. Don't know if we should start coasting before we reach 1c or just the hell with it and see what happens if we keep accelerating.

klyrs6y ago

So many people in this thread are acting like constant acceleration is possible. Unfortunately the faster you get, the more energy it takes to maintain constant acceleration.

> Don't know if we should start coasting before we reach 1c...

Don't worry about it. Your rocket would need to expend an infinite amount of energy to accelerate to c. The energy stored in your finite-sized rocket is finite. At a certain point it becomes futile to keep trying to accelerate -- though I suspect that the impacts of space dust will eventually cause a significant amount of drag

http://math.ucr.edu/home/baez/physics/Relativity/SR/Rocket/r...

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tunesmithOP6y ago

Can you alternate accelerating and decelerating? I mean that's a heck of a lot more energy, but at least you're not risking reaching light speeds.

quickthrower26y ago· 2 in thread

Wouldn't 1g be perfect? I've been enjoying it for a few years now on this planet.

tunesmithOP6y ago

I took it as 1g of acceleration. I don't know. Wouldn't plain old 1g mean no acceleration at all?

Edit: Oh... I guess not. :) I got confused with the extra g's we'd need to escape earth, but that's so short-term that it can be ignored. Yeah, I think 1g would be perfect.

quickthrower26y ago

When you sit in a car and it accelerates forward you can feel your back being pushed into the seat. When you lie in bed gravity will also push you into the bed. In both cases it's a force acting on your body. So being pushed in space in a ship accelerating at 1g will feel like normal gravity with the 'ground' being the back of the ship.

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7 comments · 2 top-level

healsjnr16y ago· 3 in thread

1G would be great as it would remove any unexpected physiological impacts of living in zero or low gravity.

Having said that, the distance and duration means that only a small portion of this journey would be under acceleration, the rest would be in zero g.

Spending a century in zero g would probably have a bunch of strange side effects and almost certainly mean that the people alive when they arrived wouldn't be able to stand the planets gravity.

This exact topic is what about 80% of The Expanse is about.

bestest6y ago

Not quite true. You'd spend half of the travel time under 1g accelerating, then the ship does a 180 degree flip in 0g, and then you spend another half of the travel time under 1g decelerating.

klyrs6y ago

So many people in this thread are acting like constant acceleration is possible. Unfortunately the faster you get, the more energy it takes to maintain constant acceleration.

> Don't know if we should start coasting before we reach 1c...

http://math.ucr.edu/home/baez/physics/Relativity/SR/Rocket/r...

1 more reply

tunesmithOP6y ago

Can you alternate accelerating and decelerating? I mean that's a heck of a lot more energy, but at least you're not risking reaching light speeds.

quickthrower26y ago· 2 in thread

Wouldn't 1g be perfect? I've been enjoying it for a few years now on this planet.

tunesmithOP6y ago

I took it as 1g of acceleration. I don't know. Wouldn't plain old 1g mean no acceleration at all?

Edit: Oh... I guess not. :) I got confused with the extra g's we'd need to escape earth, but that's so short-term that it can be ignored. Yeah, I think 1g would be perfect.

quickthrower26y ago

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