The only way to travel the speed of light is to use it as a propellant.

a reply to: JoshuaCox

Solar sails used in conjunction with ion engines may allow us eventually move around our own system but as to a method of flt travel between the stars its simply not a viable option.

For a start slowing down from a significant percentage of light speed may present a whole manner of problems where sails are concerned.

a reply to: TheJesuit

If you use light as a propellant then the highest velocity you could achieve would be "almost light speed."

There are events that take place faster than light speed (spooky action over a distance) that humanity needs to investigate because we don't know the mechanism that allows these actions. Those are the actions that we need to emulate, rather than using light as a propellant, IMO.

a reply to: kelbtalfenek

I always liked the Philotic Parallax Instantaneous Communicator idea, more commonly known as the Ansible from Enders Game.

Two particles thus entwined, et cetera, et cetera seems to have done the trick. Might even be possible in reality, no idea how we would create such all the same, maybe those clever Monkeys at C.E.R.N are on the job as we speak?

a reply to: Gothmog

I spent time writing a longer reply but had issues when I tried to submit it, so I'll have another quick stab at it.

In the OP, they asked the question '[is there] ANY theory on using LIGHT as a propellant in space', and that question has been answered several times in this thread.

Photonic Propulsion - Google Search

[...] Photonic propulsion is very similar to how a boat sails downward (in the direction of gusty winds) in an ocean. The boats use a sail that “catches wind” to thrust forward. Similarly, photonic propulsion systems require a solar sail to “catch light”.

The incoming exuberant photons exert a force on the sail particles. The particles, dutifully obeying Newton’s 3rd law of motion, exert an equal and opposite force back.

- What Is Photonic Propulsion?

A propellant is a force or substance that drives something else forward. Your model rocket needs a propellant, or a fuel to push it into the air. You might use something as simple as vinegar and baking soda. Space rockets use solid or liquid propellants, or fuel.

- Vocabulary.com

a reply to: andy06shake

partially cloaking a vehicles frame of reference to the outside world would explain much of the ufo sightings. and it would allow you to travel around the solar system at very, very fast speeds. close enough to light speed (say 2/3rds) to get around just fine and fast enough.

but to travel faster than light the most sensible solution would be to locally alter the metrics of the vacuum to increase the speed of light so that inside that localized bubble you do not incure the problematic effects of approaching lights speed since the goal post has been moved so far ahead that you never come close enough to "light speed" in that bubble to warrant any relativistic effects.

another thought experiment. if you completely cloak your frame of reference from the rest of the universe to decouple all together. and the universe has no idea you are travelling. would you ultimately be able to travel so fast that you essentially appear to teleport from place to place. same goes with ideas like superconducting the vacuum somehow. if light has an infinite speed limit where it conducts instantaneously everywhere would you be travelling infinitely fast. teleporting essentially granted you don't run into something in your way. that could be really dangerous. what if in experiments into rigs that could accomplish that the vehicle and it's crew just wink out and reappear somewhere across the known universe never to be seen again. literally lost in space. or if you are superconducting the vacuum. what happens if you run into a patch of the universe where the vacuum is not homogeneous and that tinsy change in density normally negligible has now become a mole hill turned into a mountain and you go splat cause the machinery and or computers responsible for maintaining this superconduction cant keep up. would you go out in a blaze of light and cerenkov radiation as you instantly drop below ftl.

Mass of an object doesn't go to infinity as you approach the speed of light.

This is down to a mis-understanding and also a mis teaching in popular science of the formula E=mc^2 which isn't the full equation, and there isn't anything in that question in particular that predicts anything to do with velocity.

The mis-interpretation is that the full formula is the invarient-mass

E^2 = P^2C^2 + M^2C^4

This still doesn't say mass goes to infinity, it says that as you increase, more of your total energy is momentum. That is all it says. Where people go off the rails is one of the appreciated forms in terms of fractional speed of light.

E = gamma MC^2 where gamma = 1/ sqrt(1-V^2/C^2)

The point of confusion is the labelling of gamma M as the 'relativistic mass' it isn't real mass, it is a combination of momentum and mass.

I've been thinking about this for a weeks. Thanks for starting the conversation.

a reply to: BASSPLYR

"another thought experiment. if you completely cloak your frame of reference from the rest of the universe to decouple all together. and the universe has no idea you are travelling. would you ultimately be able to travel so fast that you essentially appear to teleport from place to place."

Where would you end up and could you find your way home to our own verse would be my major questions.

Could the universe lose us, or could we lose the universe for that matter?

Sounds like the premise to "Lost In Space" LoL

Non the less interesting questions to ponder.

I thought economics made my head hurt!

According to a couple sources, the edge of the universe is travelling faster than light. It's being propelled by dark energy.

www.space.com...

So does this not negate the theory that matter cannot exceed light speed? I dunno, just speculating. Then there is the matter of slowing down, and or, avoiding solid objects.

a reply to: BASSPLYR

That's really really interesting....

I've actually read one or two things here on ATS that give me a tiny nugget of insight into what you may possibly be talking about...

Thanks you

originally posted by: oldcarpy
a reply to: Gothmog


So, why do you think that you can't have a lit torch in space, then?

I apologize . Torch has a different meaning to me. I later caught myself and realized not everyone speaks the bastardized English (US)

originally posted by: JoshuaCox
a reply to: Gothmog

What do you think solar sails are lol??

You really need to keep to the political threads....lol????

originally posted by: MerkabaTribeEntity
a reply to: Gothmog

I spent time writing a longer reply but had issues when I tried to submit it, so I'll have another quick stab at it.

In the OP, they asked the question '[is there] ANY theory on using LIGHT as a propellant in space', and that question has been answered several times in this thread.

Photonic Propulsion - Google Search

[...] Photonic propulsion is very similar to how a boat sails downward (in the direction of gusty winds) in an ocean. The boats use a sail that “catches wind” to thrust forward. Similarly, photonic propulsion systems require a solar sail to “catch light”.

The incoming exuberant photons exert a force on the sail particles. The particles, dutifully obeying Newton’s 3rd law of motion, exert an equal and opposite force back.

- What Is Photonic Propulsion?

A propellant is a force or substance that drives something else forward. Your model rocket needs a propellant, or a fuel to push it into the air. You might use something as simple as vinegar and baking soda. Space rockets use solid or liquid propellants, or fuel.

- Vocabulary.com

Once more , just for you , the Thread title . Bolded. Read

The only way to travel the speed of light is to use it as a propellant.

Although the fact that light (nay photons ) is a "propellant" , it could NEVER be used to propel any mass at the speed of light for VERY obvious reasons . (all the Laws of physics , mass , and motion )
I am not impressed by walls of text.

originally posted by: TheJesuit
Im no scientist but if you were to travel the speed of light wouldn't you have to use light as a fuel to push propel -whatever - in space and just wait to gather up speed the problem after traveling that far would be acquiring another light source.... lol .. Solved it!

Any theory on using LIGHT as a propellant in space? or on Earth? Gravity would be a monkey wrench though.

Light sails. Been a thing forever.

Lasers propel it or starlight. Suns.

a reply to: Gothmog


Thanks - I see now!

originally posted by: Hammaraxx
Something to consider about light speed and matter.
If the 'bits and pieces' of atoms in an object have to move about to keep the atom together, what would happen to atoms at the speed of light?
To stay together, they would have to be travelling faster than the speed of light, at least in the direction of travel, which is theoretically impossible.
Perhaps, not impossible, but theoretically impossible according to our current understandings/thinking.

Seems to me that, since as you approach light speed the mass approaches infinity, at some point the mass is great enough that you would produce a 'mini' black hole and essentially wink out of existence.

(Edit: and the 'bits and pieces' of atoms do not travel at the speed of light, so they could still stay some percentage less than the speed of light and still stay within the speed limit. Except that the mass/gravity problem that mentioned above would 'squish' them out of any semblance to an atom.)

originally posted by: lakenheath24
I thought economics made my head hurt!

According to a couple sources, the edge of the universe is travelling faster than light. It's being propelled by dark energy.

www.space.com...

So does this not negate the theory that matter cannot exceed light speed? I dunno, just speculating. Then there is the matter of slowing down, and or, avoiding solid objects.

Need at least 4 black holes under the hood to do it the hard way.

1.5 C the hard way

Space debris will go right through you. No prob.

a reply to: Gothmog

You claimed that a solar sail would take "5 years to reach 100 mph".

I showed you were wrong.

You claimed that "light in itself [isn't] a propellant".

I showed you were wrong.

Once more, just for you, the simple question from the OP that I was responding to (in BOLD);

[Is there] ANY theory on using LIGHT as a propellant in space?

The answer is quite clearly yes.

Nowhere, in either the question that I was responding to nor in any of my replies, does it suggest or make the claim that solar sails could reach light-speed velocity.

Yes, that is a question posed by the OP, but that wasn't the question I was responding to.

Is this all beginning to make sense to you yet? Or is this still too many words for you to process in one go?

a reply to: TheJesuit

Found the troll-science videos on youtube?

a reply to: Whoisjohngalt

yeh that is the idea , to get everything else to move, but wouldnt that also require lots of energy

I thought moving down a level where less energy is required, or in between layers where there is no time ,.


I thought the whole problem with light speed, was that "light" is the only thing found to travel at that speed, nothing moves faster
only in theory could particles travel faster than light, and those are tachyons and they are theoretical.

So we are stuck in this world where light determines everything