6 ms·

The Physics of Building a Black Hole Powered Starship [pdf]

44 points by awwx 17y ago

caffeine 17y ago
This is really, really cool. And this is obviously how they powered Rama.
bioweek 17y ago
They don't seem to mention how to contain the black hole. What holds its position steady within the spaceship? If we made a large enough one say 1/2 earth mass, we'd get free "artificial" gravity on the spaceship.
- amix 17y ago
  Their proposed blackholes are small - some of their calculations use 4 × 10^11 grams [440.924 tons ~ comparable to Empire State Building which weights about 300.000 tons].
- randallsquared 17y ago
  The radiation involved means that you probably couldn't shield a human well enough to be close enough to one of these black holes to feel gravity. Not to mention tidal forces.
- bioweek 17y ago
  I meant, how do you stop the black hole from hitting the spaceship, moving around, falling out the back, etc?
  - awwx 17y ago
    They touch on this briefly at the top of page 11: "The most optimistic approach is to solve requirements 2 [accelerate the black hole to keep it with the ship] and 3 [feeding the black hole with matter so that it doesn't evaporate] together by attaching particle beams to the body of the ship behind the BH and beaming in matter. This would both accelerate the SBH, since BHs “move when you push them” (see [3] p270), and add mass to the SBH, extending the lifetime." The engineering details are left as an exercise for the reader :-)
nicara 17y ago
"It is now known that any prolonged human presence deeper in space would need to be behind a shield of the effective strength of two feet of lead, which would weigh 400 tonnes for a small capsule." Uhm, the first thing that comes to my mind - regardless of whether this black hole propulsion might actually work - is the amount of lead we have available. Just building the spaceship seems to be just as much a problem as accelerating it..
- thaumaturgy 17y ago
  Effective shielding against cosmic radiation is possibly an even greater problem in interplanetary travel than propulsion. The solution will probably come from materials science, but at the moment I don't think there's enough effort being concentrated on this problem to solve it in my lifetime.
  - electromagnetic 17y ago
    Would placing the spaceships crew behind its black hole engine provide adequate shielding from cosmic radiation and blue-shifted photons/particles? Killing two birds with one black hole, so to speak. Also, wouldn't being in such proximity to a black hole negate the need for time dilation effects of speed anyway? If you can build black holes, speed is meaningless as you essentially have a stasis machine. You could travel at .1c, reach Alpha Centauri in 40+ years and never even age a day if you can get close enough to the event horizon.
    - pyre 17y ago
      How do you place the crew 'behind' the black hole? Space is 360 degrees.
      - electromagnetic 17y ago
        Actually space is ~130,000 degrees (slightly less, disappointing I know) because it's 3 dimensional, not 2D. However I was talking about a vehicles design here, and suggesting an engine-in-front design rather than an engine-behind. Like the humble car, an engine-in-front design may protect the driver from nasty impacts, in this case blue-shifted gamma rays and microscopic particles that have been blue-shifted to the point that your ship is in a giant particle collider. If you could hide the crew in a sort of eclipsed position behind (in relation to the direction of momentum) the event horizon would act as a shield. This would mean you only had to harden equipment against radiation, rather than find a way to protect the crew themselves. IMO though, if you've built a black hole, you might as well be moving something big, as in either a planet, small moon, or giant colony. On these scales the need to travel fast would become redundant, your colony ship could be so big it could literally house a world. Then an organisation like NASA would essentially become a planetary bus-driver association.
deleted 17y ago
[deleted]
bitwize 17y ago
I saw this headline and flashed back to the Gunbuster Science Lessons. "Dimensional Wave Super String Excitation Degenerated Radius Jump Gravitational Field Super-light Speed Navigation. WARP for short."

44 points by awwx 17y ago

This is really, really cool. And this is obviously how they powered Rama.

They don't seem to mention how to contain the black hole. What holds its position steady within the spaceship? If we made a large enough one say 1/2 earth mass, we'd get free "artificial" gravity on the spaceship.

amix 17y ago
Their proposed blackholes are small - some of their calculations use 4 × 10^11 grams [440.924 tons ~ comparable to Empire State Building which weights about 300.000 tons].
randallsquared 17y ago
The radiation involved means that you probably couldn't shield a human well enough to be close enough to one of these black holes to feel gravity. Not to mention tidal forces.
bioweek 17y ago
I meant, how do you stop the black hole from hitting the spaceship, moving around, falling out the back, etc?
- awwx 17y ago
  They touch on this briefly at the top of page 11: "The most optimistic approach is to solve requirements 2 [accelerate the black hole to keep it with the ship] and 3 [feeding the black hole with matter so that it doesn't evaporate] together by attaching particle beams to the body of the ship behind the BH and beaming in matter. This would both accelerate the SBH, since BHs “move when you push them” (see [3] p270), and add mass to the SBH, extending the lifetime." The engineering details are left as an exercise for the reader :-)

nicara 17y ago

"It is now known that any prolonged human presence deeper in space would need to be behind a shield of the effective strength of two feet of lead, which would weigh 400 tonnes for a small capsule." Uhm, the first thing that comes to my mind - regardless of whether this black hole propulsion might actually work - is the amount of lead we have available. Just building the spaceship seems to be just as much a problem as accelerating it..

thaumaturgy 17y ago
Effective shielding against cosmic radiation is possibly an even greater problem in interplanetary travel than propulsion. The solution will probably come from materials science, but at the moment I don't think there's enough effort being concentrated on this problem to solve it in my lifetime.
- electromagnetic 17y ago
  Would placing the spaceships crew behind its black hole engine provide adequate shielding from cosmic radiation and blue-shifted photons/particles? Killing two birds with one black hole, so to speak. Also, wouldn't being in such proximity to a black hole negate the need for time dilation effects of speed anyway? If you can build black holes, speed is meaningless as you essentially have a stasis machine. You could travel at .1c, reach Alpha Centauri in 40+ years and never even age a day if you can get close enough to the event horizon.
  - pyre 17y ago
    How do you place the crew 'behind' the black hole? Space is 360 degrees.
    - electromagnetic 17y ago
      Actually space is ~130,000 degrees (slightly less, disappointing I know) because it's 3 dimensional, not 2D. However I was talking about a vehicles design here, and suggesting an engine-in-front design rather than an engine-behind. Like the humble car, an engine-in-front design may protect the driver from nasty impacts, in this case blue-shifted gamma rays and microscopic particles that have been blue-shifted to the point that your ship is in a giant particle collider. If you could hide the crew in a sort of eclipsed position behind (in relation to the direction of momentum) the event horizon would act as a shield. This would mean you only had to harden equipment against radiation, rather than find a way to protect the crew themselves. IMO though, if you've built a black hole, you might as well be moving something big, as in either a planet, small moon, or giant colony. On these scales the need to travel fast would become redundant, your colony ship could be so big it could literally house a world. Then an organisation like NASA would essentially become a planetary bus-driver association.

deleted 17y ago

[deleted]

bitwize 17y ago

I saw this headline and flashed back to the Gunbuster Science Lessons. "Dimensional Wave Super String Excitation Degenerated Radius Jump Gravitational Field Super-light Speed Navigation. WARP for short."