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Old 07-08-2019, 11:08 PM
 
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Is propellant the only way to propagate through the vastness of space?

Is gravitational pull considered a form of propagation?

How does electro-magnetism travel through vacuum like photons? Photons are being projected, but doesnt it need an opposite and equal action for it to shoot out? What is that action?
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Old 07-08-2019, 11:28 PM
 
Location: Willamette Valley, Oregon
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The hard part is to leave earth's gravitational field. Once in open space, choices are abundant. The only thing needed is a buttload of energy. I, there's the rub. One way is to go slowly and live a very long time. "Methuselah's Children" Heinlein. "Cities in flight" James Blish.
We'll figure it out someday, but not in our lifetime.
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Old 07-09-2019, 01:20 PM
 
Location: Seattle
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Solar sails don't need to use propellant. They can be propelled by lasers, for example.

Gravitational force is equivalent to acceleration, per Einstein. Gravity waves travel through space at the speed of light, so they are mass-less.

Photons have no invariant mass, so the forces in Newton's laws of motion don't apply. They do possess momentum though.
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Old 07-09-2019, 05:59 PM
 
Location: Maryland
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See this thread in this same sub-forum. I posted about an upcoming test by Cannae to confirm its operation in vacuum.

Improbable Thruster Seems to Work by Violating Known Laws of Physics

The Alcubierre Drive is another that would not use propellants in the strict sense.

https://en.m.wikipedia.org/wiki/Alcubierre_drive

Last edited by LesLucid; 07-09-2019 at 06:08 PM..
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Old 07-09-2019, 06:57 PM
 
Location: Continental Europe
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More interesting reading:

https://en.wikipedia.org/wiki/Non-rocket_spacelaunch

https://en.wikipedia.org/wiki/Interstellar_travel
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Old 07-09-2019, 07:03 PM
 
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Currently we have access to only rockets which are chemical in nature, along with nuclear propulsion which is not feasible. We can use light (photons) and know how to do it but we need to be up in space to do it.

Right now chemical propulsion is the best we can do.
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Old 07-09-2019, 09:04 PM
 
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Quote:
Originally Posted by rjshae View Post
Solar sails don't need to use propellant. They can be propelled by lasers, for example.

Gravitational force is equivalent to acceleration, per Einstein. Gravity waves travel through space at the speed of light, so they are mass-less.

Photons have no invariant mass, so the forces in Newton's laws of motion don't apply. They do possess momentum though.
Solar Sails are almost like propellant. It needs a propellant to hit it.
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Old 07-11-2019, 10:58 AM
 
Location: Seattle
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Quote:
Originally Posted by NJ Brazen_3133 View Post
Solar Sails are almost like propellant. It needs a propellant to hit it.

True, but you don't need to transport it with you so you there's no need to overcome that extra inertia.


Another possibility for propellant-less drive is using the magnetic fields found naturally in space.


https://en.wikipedia.org/wiki/Field_propulsion
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Old 07-11-2019, 04:21 PM
 
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One limitation of a solar sail however is that you can't tack back toward the sun. A sailboat can tack into the wind because it has a keel and a rudder to work against the water. That's not the case with a solar sail space craft, so it can only carry you away from the sun.

However, from what I've read, you could use the solar sail to slow your angular momentum around the sun which would cause you to fall back toward the sun due to its gravitational pull.
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Old 07-11-2019, 06:31 PM
 
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Quote:
Originally Posted by rjshae View Post
True, but you don't need to transport it with you so you there's no need to overcome that extra inertia.


Another possibility for propellant-less drive is using the magnetic fields found naturally in space.


https://en.wikipedia.org/wiki/Field_propulsion
Which actually brings me another question, I wrote in the OP. How does gravity, and Magnetism propel itself across space? I thought Magnetism, and electricity need matter to touch each other to transport itself.
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