Get to Lightspeed by using Light itself

the contemporary problem of travelling at the speed of light is that you need a certain amount of energy to move mass to that speed..the problem is to reach lightspeed you need infinite mass, well what if instead of trying to GET to lightspeed by using propulsion, we use light itself as a means of travel.

Think about it..light itself is mass, it exerts itself onto objects, otherwise it wouldnt cast shadows...what if we can tap into that source like a sailboat on the wind and use it to gain speed, thus reaching lightspeed by using light itself, and never having to use a single ounce of energy ourselves to get there

I suppose the only problem is in deep-space your light-source is limited, but if you can exert the light into a area using mirrors then even in deep-space it shouldnt be a problem and there would also be the option of energy storage until the next star system to "tap" into.

I believe the Gene Brewer book and subsequent movie: K-Pax , touched on this topic. This movie revolved around an ET that had possesed a Human body which was agreed to by the host.
Anyway this ET who was from the Constellation of Lyra went into only brief details about traveling on a beam of light. Though the ET mentioned Tachyons. Which I thought was a clue.

[edit on 23-8-2009 by Epsillion70]

[edit on 23-8-2009 by Epsillion70]

reply to post by ROBL240


Nice topic.

To add, why not find a way to artificially reduce/negate mass itself?


The weight of an object is the force of gravity on the object and may be defined as the mass times the acceleration of gravity, w = mg.

reply to post by ROBL240

....what if we can tap into that source like a sailboat on the wind and use it to gain speed, thus reaching lightspeed by using light itself...

This has been postulated in many a Science Fiction story.

.... and never having to use a single ounce of energy ourselves to get there...

Well...building the craft, supplying life support, etc, all takes energy.

I'll see if I can find a link to the "LightSail" concept.

But, while I look, consider this: HOW are you going to decelerate and stop at destination?
__________________________________

edit: Here is a link.

As you'll see, it actually was proposed for InterPlanetary travel, although certainly not at light speeds.

Another thing to consider is the amount of time needed to accelerate.

I'm still unsure how the ships can APPROACH the Sun, though...

[edit on 23 August 2009 by weedwhacker]

But, while I look, consider this: HOW are you going to decelerate and stop at destination?

Simple, use the energy stored to act as reverse thrust or simply shut off the "sails" and glide to a smooth stop.

reply to post by ROBL240

Simple, use the energy stored to act as reverse thrust or simply shut off the "sails" and glide to a smooth stop.

Ain't gonna work like that, mate!

ALL of the energy (from hte light pressure) that went into getting you up to a certain speed, is EQUAL to the amount of energy needed to slow you back to your starting velocity. Newtonian physics, very basic.

SO, you have to have some sort of engine (how did you "store" energy???) and fuel for that engine...you might as well use the engine in the first place! Ah, but that's a lot of mass....which you DON'T want, because it directly affects your ability to accelerate/decelerate.

Folding the sails won't work, either. All that will happen? You stop accelerating, but then you maintain a steady speed. No friction in space, remember? That pesky Newton, again!!

Actually, space is not empty. There are molecules and gas and dust spread out much more than on earth, but they are there. When someone falls towards earth they reach terminal velocity because the force of the air particles counteract acceleration, that's why you can only fall at around 120 mph.

In space, these particles would do the same thing - you can accelerate towards light, but the "friction" from all of these particles would result in you requiring more and more energy to "power" through them, this is not even taking into account the relativistic side of things.

That there are particles in space is of no doubt but to consider using them to slow you down is not a good idea in my opionon.

I cant see that being very plausible as that would mean knowing the particle density over the entire journey so you could calculate when to pull in the sails.

So as previous posters have said your gonna have to have an engine that can produce enough reverse thrust to slow you down.


I think we will need to wait for a greater understanding of physics before we can travel at the speed of light or faster.

In the past there where people who said you could not go faster then 50mph then 100mph then 200mph then the speed of sound.

Everytime someone went faster the goal posts get moved what happens when we finally break the spped of light? Will the goal posts be moved again?

reply to post by Speedtek

...you can accelerate towards light, but the "friction" from all of these particles would result in you requiring more and more energy to "power" through them...

No, you have it backwards.

You accelerate AWAY from the light source (in this example, the Star you are using. Lasers have been suggested as motive force, but they would have a limited ranbge, I'd think).

Also, all of those "particles" are more of a problem than just causing "friction"!! No, they are very dangerous, at high velocity. There will need to be some sort of shielding to protect the spacecraft. Most likely is a plasma-based type, perhaps something electro-magnetic....

Basically, we need Star Trek type shields.

Originally posted by ROBL240
...the problem is to reach lightspeed you need infinite mass, well what if instead of trying to GET to lightspeed by using propulsion, we use light itself as a means of travel.

Think about it..light itself is mass, it exerts itself onto objects, otherwise it wouldnt cast shadows...

Light is massless -- light is made of photons, and photons have "zero" mass (that's why they can travel the speed of light).

...also, when an object casts a shadow in light, photons are absorbed or reflected by that object. Photons do not need to have mass to be absorbed or reflected.


[edit on 8/24/2009 by Soylent Green Is People]

Originally posted by Soylent Green Is People

Originally posted by ROBL240
...the problem is to reach lightspeed you need infinite mass, well what if instead of trying to GET to lightspeed by using propulsion, we use light itself as a means of travel.

Think about it..light itself is mass, it exerts itself onto objects, otherwise it wouldnt cast shadows...

Light is massless -- light is made of photons, and photons have "zero" mass (that's why they can travel the speed of light).

...also, when an object casts a shadow in light, photons are absorbed or reflected by that object. Photons do not need to have mass to be absorbed or reflected.


[edit on 8/24/2009 by Soylent Green Is People]

but can light be used the same way electricity is used, just like electricity flows through wires and turns an electric motor ?..
im thinking light flowing through tubes and turning a light motor to nearly the speed of light rpm...
i know it sounds crazy ...

reply to post by ROBL240


Food for thought:

In the "Millennial" book series by Charles James Hall, Hall claimed that the Tall Whites told him to look into the properties of light in answer to Hall's question about how they powered their crafts (capable of interstellar travel). After Hall's retirement from the military he became educated as a physicist and published several papers on the properties of light.

It has been postulated that "light interference" or essentially firing light upon itself in sequenced beams in the X, Y, and Z axis, ie photons colliding, will produce gravity waves which when focused could be used for propulsion. I haven't heard of any progress in this technique but if anyone has, please advise.

reply to post by ROBL240


Light doesn't cast shadows.. that's the absence of light.

also light (photons) has mass.
not just when traveleing at the speed of light (sol)

Light only travels that fast in a vacuum.

Originally posted by Tetragrammaton
also light (photons) has mass.
not just when traveling at the speed of light (sol)

so do you think photons would have enough energy to power an engine , im thinking a light \ photon engine just like electricity powers an electric engine.. i know there's know such thing as a photon engine but im just guessing at a possible engine that could power a spacecraft...

Originally posted by Tetragrammaton
also light (photons) has mass.
not just when traveleing at the speed of light (sol)

No, photons are massless all the time. They have a "rest mass" of zero (although they can never be brought to rest *[see note below]). Their "proper mass" when moving is also zero.

What may confuse people is that if E=mc^2, and photons have energy, then it would seem that photons must have mass -- after all, where is the energy coming from? HOWEVER, E=mc^2 is not exactly correct...it can only be used to describe particles at rest. The proper equation for particles in motion that should be used in lieu of the famous E= mc^2 is:

E^2 = m^2c^4 + p^2c^2

where p = momentum

A moving particle with no mass (such as a photon) still has momentum, thus it has energy. The energy comes from the momentum, not the mass. In the case of a photon, because the mass = 0 the above equation could be reduced to E=pc (Energy = momentum x the speed of light)

Now, in the case of a photon at rest (which is not possible* [see note below]), the photon's mass is still zero. Its momentum (p) is also zero, because it is at rest. In this case, since momentum (p) = 0, then we can go back to Einstein's equation E=mc^2. So using E=mc^2, the total rest energy of a photon is zero.

By the way, even though it is impossible for a photon to be at rest, we can still talk about its properties while at rest as if it could be at rest.

So, the bottom line is that all of a photon's energy comes from its momentum, NOT its mass. Its "proper mass" and its "resting mass" are both equal to zero.

HOWEVER, back to the OP's question...
...perhaps the momentum of photons can be harnessed to help another object to get to the speed of light.

* Note: I know scientists have "slowed down" light, but that's a totally different concept; they did not actually slow down the photons.



[edit on 8/26/2009 by Soylent Green Is People]

Light moves at different speeds depending on the medium, 'c' is only a constant in a vacuum.

They have managed to pulse light to 300 times it's speed through a specially treated Caesium gas.

www.science-spirit.org...

Also, it has been shown that light can repel and attract itslef, maybe it is on the microscale, but it does have implications. Similar to the Casimir effect.

www.technologyreview.com...

EMM

[edit on 26-8-2009 by ElectroMagnetic Multivers]

reply to post by Soylent Green Is People


depends on your point of view. dont state it as fact.
its like particles, they are either a wave or particle depending on what the observer expects to find
quantum mechanics.

nothing you said refuted my claim, everything has mass, even photons
but when traveling at the speed of light or near the speed of light it just looks at it doesnt has mass, nevertheless, the mass is still there

you are right though, our relativity tells us that you need to bring the photon to zero speed, for it to have mass.

i say, aswell as other physicist, that the photons mass increase with the decreasing of its speed.


@ can you use photons to travel at SOL?

not sure, im guessing that if you want to travel at SOL you would need to think out of the box.
im more into folding space theories, using wormholes / anomolies etc.

even at the speed of light it would take ages to get around in the universe.

my point being that if you observed a photon traveling in vacuum, at C. while you yourself are travelling along side it in vacuum at C, it would have mass