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Oumuamua may be a hydrogen iceberg

news.yale.edu

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Re: Oumuamua may be a hydrogen iceberg

#31

Post by jandrese »

throwaway2048 wrote: post #28
ISL wrote: post #13

Earlier quoted context omitted.

Unless you can fuse it into helium.

If you have the tech to fuse hydrogen the amount of fuel you would need for a nearly unlimited amount of energy is tiny, you would save very little by harvesting it off a comet/asteroid.

Depends on how much energy you need. If you are talking about turning it into an interstellar spacecraft by hooking up some kind of fusion powered thruster (probably using H2 as the reaction mass) to the back you may need all of its mass.

This is of course well beyond our current capabilities, but it's not something that's impossible to consider in the medium-distant future. Plus, even if you expend a colossal amount of energy accelerating you're still talking about thousands of years for the journey where you'll need to keep those reactors running for the entire trip (there is no useful solar collection in deep space) having a literal mountain of fuel to start with is important.

Re: Oumuamua may be a hydrogen iceberg

#32

Post by jandrese »

whatshisface wrote: post #15
dmitrygr wrote: post #10

Earlier quoted context omitted.

Complete lack of motion would violate Heisenberg uncertainty principle ("no motion" == "I know both momentum and location with zero uncertainty" and that's not allowed)

No, you can have zero momentum. However it comes along with having a position wavefunction that fills the whole universe.

The universe kindly requests that you do not divide by zero.

Re: Oumuamua may be a hydrogen iceberg

#34

Post by Sharlin »

throwaway2048 wrote: post #28
ISL wrote: post #13

Earlier quoted context omitted.

Unless you can fuse it into helium.

If you have the tech to fuse hydrogen the amount of fuel you would need for a nearly unlimited amount of energy is tiny, you would save very little by harvesting it off a comet/asteroid.

You still need propellant mass. Energy in itself doesn't get you anywhere. But in practice you'd probably be better off electrolyzing water ice which is ubiquitous in the outer Solar System.

Re: Oumuamua may be a hydrogen iceberg

#35

Post by aj7 »

fenwick67 wrote: post #3

This is great sci-fi fodder, imagine if you could land a tiny craft on that thing and then use the hydrogen as fuel without having to haul all that fuel into deep space (very unlikely to be practical but the idea is exciting).

Or just follow it.

Re: Oumuamua may be a hydrogen iceberg

#37

Post by Symmetry »

fenwick67 wrote: post #3

This is great sci-fi fodder, imagine if you could land a tiny craft on that thing and then use the hydrogen as fuel without having to haul all that fuel into deep space (very unlikely to be practical but the idea is exciting).

Yeah, though there's lots of water in the outer solar system you can get your propellant from. The term to google is In Situ Resource Utalization (ISRU).

https://en.wikipedia.org/wiki/In_situ_resource_utilization

Re: Oumuamua may be a hydrogen iceberg

#38

Post by aj7 »

caymanjim wrote: post #16
crimsonalucard1 wrote: post #4

Is there an element or compound in the universe that will remain a gas at 0K? Does everything become solid at that temp?

To be pedantic, it's impossible to get to 0K due to quantum fluctuations. Even empty deep space is over 2K. In laboratory settings, we've gotten way below 1K. I don't think anything qualifies as a gas at that temperature. It'd be a solid or a BEC.

https://m.timesofindia.com/home/science/Lowest-temperature-e...

Re: Oumuamua may be a hydrogen iceberg

#39

Post by scotty79 »

throwaway2048 wrote: post #28
ISL wrote: post #13

Earlier quoted context omitted.

Unless you can fuse it into helium.

If you have the tech to fuse hydrogen the amount of fuel you would need for a nearly unlimited amount of energy is tiny, you would save very little by harvesting it off a comet/asteroid.

Unless you just want to colonize this hydrogen iceberg, and live on it for next thousand years, recycling all other elements indefinitely as you cruise through the galaxy.

Re: Oumuamua may be a hydrogen iceberg

#40

Post by rfreytag »

ISL wrote: post #13
diroussel wrote: post #11

Earlier quoted context omitted.

Then the problem becomes getting oxygen. As a hydrogen won't burn in a vacuum.

Unless you can fuse it into helium.

Insulating the fusion reactor from the solid hydrogen in Oumuamua could prove difficult.
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