The Astronomy Thread

Tuco

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I kind of miss the EMDrive drama. Following the retarded theorycrafting at the nasa space flight forum of dumbasses using modeling software to come up with more efficient emdrives was great.

It still feels like any kind of non-propellant drive that can't be proven beyond reasonable doubt on Earth would be difficult to prove in space. I couldn't find out how heavy the satellite is, but if it truly generates 10 mN of force over an extended period it should be pretty obvious whether it works or not unless they try to scam people with some bullshit ion thruster or something. Very exciting!
 
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Ukerric

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"You pay, we launch, no questions asked. It's your money."
I kind of miss the EMDrive drama. Following the retarded theorycrafting at the nasa space flight forum of dumbasses using modeling software to come up with more efficient emdrives was great.

It still feels like any kind of non-propellant drive that can't be proven beyond reasonable doubt on Earth would be difficult to prove in space. I couldn't find out how heavy the satellite is, but if it truly generates 10 mN of force over an extended period it should be pretty obvious whether it works or not unless they try to scam people with some bullshit ion thruster or something. Very exciting!
It's easier to measure, but way easier to scam though, as no one can check the actual satellite to see if there's no small ion "leak".
 
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meStevo

I think your wife's a bigfoot gus.
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1689189700786.png
 
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Furry

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Yes. On a small planetoid, it's possible, but a large mass above the spheroid limit will absolutely collapse.
This is absolutely incorrect. The planet would have to rotate at the appropriate speed to maintain equilibrium with the forces that would destroy it. Even a black hole could theoretically be a torus.
 

Captain Suave

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This is absolutely incorrect. The planet would have to rotate at the appropriate speed to maintain equilibrium with the forces that would destroy it. Even a black hole could theoretically be a torus.

For the curious:


Noteworthy: "[There is] no firm theoretical understanding as to how toroidal planets could form naturally"

For the super-curious, some math about the allowable geometries and speeds:

 
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Captain Suave

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This tweet is probably bullshit.


It's a technologically cool idea and has been done small scale by several research groups, but not remotely economical at present. If anyone could make that work if they wanted to, it's Elon.
 

Big Phoenix

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And wouldnt they just be dumping it right back into the atmosphere if theyre combusting it(I assume methane is the end product)?
 
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Tuco

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And wouldnt they just be dumping it right back into the atmosphere if theyre combusting it(I assume methane is the end product)?
Yes. Except for the fuel they put into orbit and use to get to L2 or moon or mars or whatever.
 

Cybsled

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And wouldnt they just be dumping it right back into the atmosphere if theyre combusting it(I assume methane is the end product)?

You have to recall his frame of view is “what can be made on site on Mars?”. The whole reason Starship will be using the fuel it is using is because he wants to be able to produce fuel on Mars to make trips back much easier.

If you don’t need to leave Earth with fuel for a return trip, that leaves more room for payload and living quarters, as well as reduces weight requirements
 
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Tuco

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I wonder how many gallons this is and whether that's the target amount for a lift.
 
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