How can you move in space?

[[Tycho?]]

How does one move in space?

As others have said' date=' by throwing something in the opposite direction - the principle of the rocket.

 

The force from this is equal to mass times velocity squared.

Mass. the more you throw, the more you move.

Velocity. the faster you throw, the faster, squared, you move.

 

What this means, is that the best means of moving in vacuum is to fire mass in the opposite direction at enormous speed. Current Earth to orbit spacecraft tend to work the wrong way. They depend on lots of mass rather than lots of velocity in their exhaust (what is thrown away).

 

A really efficient space craft will fire lots of mass, but at enormous velocity. The fastest speed achievable, for the matter thrown away, is close to the speed of light. Thus, the best rocket for the vacuum of space is a linear accelerator, that fires heavy atoms such as Xenon at close to the speed of light. Over a period of time, this will permit the rocket to accelerate in the opposite direction to very high speed.

 

How does one escape a black hole.

As the very first reply said, it is impossible. To be in a black hole, by definition, means being inside the event horizon. Once you are there, you are gone. In fact, you will be torn apart by tidal forces as you spiral down into the singularity.[/quote']

 

Force is not equal to mv^2. Its F=ma.

[Klaynos]

'']Force is not equal to mv^2. Its F=ma.

 

I do feel as we're doing rocket science, F=ma should NOT be used:

 

[math]F= \frac {dp} {dt}= \frac {d(mv)} {dt}[/math]

[ydoaPs]

Klaynos, doesn't [math]\frac{d(mv)}{dt}=ma[/math]?

[Klaynos]

Klaynos, doesn't [math]\frac{d(mv)}{dt}=ma[/math']?

 

Only if there is constant mass. The idea of most rocket type engines (including ion engines etc...) is that the mass changes.

[ydoaPs]

Only if there is constant mass. The idea of most rocket type engines (including ion engines etc...) is that the mass changes.

ah, i didn't think of that. i just assumed mass was a constant. i should have thought of that since mass is expelled to induce the change in momentum. i feel so stupid now.

 

[math]\frac{d(mv)}{dt}=ma+v{\frac{dm}{dt}}[/math]

[swansont]

ah' date=' i didn't think of that. i just assumed mass was a constant. i should have thought of that since mass is expelled to induce the change in momentum. i feel so stupid now.

 

[math']\frac{d(mv)}{dt}=ma+v{\frac{dm}{dt}}[/math]

 

You should feel smarter now, shouldn't you?

[ydoaPs]

Wow! Basic calculus!!!!!! I'm so smart!

[gcol]

I thought that everything was moving relative to everything else anyway, so you need to do nothing to move in space.

 

Or else just stay where you are and have a siesta and wait for the rest of the universe to shift itself. No expenditure of personal effort whatsoever. Job done.

[Severian]

Only helps if you aren't wearing a spacesuit. If you are, I imagine it's ghastly.

 

Presumably you could have some sort of pressure valve fitted.

[Klaynos]

I thought that everything was moving relative to everything else anyway' date=' so you need to do nothing to move in space.

 

Or else just stay where you are and have a siesta and wait for the rest of the universe to shift itself. No expenditure of personal effort whatsoever. Job done.[/quote']

 

 

It might not be moving in the way you want, or fast enough in the direction you want. You've also got to a velocity where the gravity from whatever you're leaving (normally the earth in our case) isn't strong enough so that after a short time you just fall back to where you started....

[swansont]

Presumably you could have some sort of pressure valve fitted.

 

Isn't that what your sphincter is?

[gcol]

It might not be moving in the way you want, or fast enough in the direction you want. .

 

 

So I will just cancel the food parcels, embargo the oil, and freeze all aid until it conforms. Dont want no terrorist commie anti-capitalist universe out there getting in my way.

[Severian]

Isn't that what your sphincter is?

 

I don't think it is strong enough. I am not sure you could clench your butt tightly enough to prevent your innards being sucked out into space.

[dirtyamerica]

When I was talking about the idea of farting I meant in theory. Sure, you would have to be naked which means inside a space capsule under pressure so you don't die or blow your guts out, obviously. Some of you are talking about needing to push off something to move...when you fart you are pushing off of your intestinal gases...a rocket is propelled by gaseous releases (although it's also exploding gas). Sure, a fart would propel you very slowly but technically it would work (I challenge future astronauts to try this and/or ignite their farts for added thrust). Solar sails propel a vessel in space VERY SLOWLY but over time it can travel very fast. The original question was "Can you move in space?"...yes, you can. Dirtyamerica(n) style.

[SkepticLance]

Frog said :

 

I'm still wondering if my organism can escape the black hole? It doesn't have to be perfect, but it has to make SOME kind of sense.

 

Can quantum tunnelling work?

 

Sorry Frog.

As said before, cain't be done!!!

if you are in a black hole (below the event horizon), you are there forever.

[Ophiolite]

if you are in a black hole (below the event horizon)' date=' you are there forever.[/quote']And so are your farts.

The first observation is called physics.

The second observation is called philosophy.

[Edtharan]

If you had a torch, you could use that to propel yourself (although extremely slowly). As light is not matter you don't use any matter to give yourself a push.

[J.C.MacSwell]

I don't think it is strong enough. I am not sure you could clench your butt tightly enough to prevent your innards being sucked out into space.

 

I think you can, at least temporarily, it's only another 14.7 psi. Eventually you will get tired though, same as on Earth except sooner.