Is Speed of Light Human Travel Possible?

[Biomega]

"Is it possible for humans to travel at the speed of light?"

Answer: No, not under our current understanding of physics. Which is incomplete and ever-expanding.

That's as good as you're going to get, for now. There's some approaches one way or the other, but more work needs to be done before the answer changes in a meaningful way.

And by the way, "Is it possible for humans to cross distances in a time shorter than it would take light to cross that distance in a vacuum?" is a very different question. It does have the same answer, for now, but it's the more likely of the two to actually change anytime soon. Not that it'll necessarily happen, just more likely.

[Kujako]

That is a confusion of terms. What most people mean when they speak about speed of light, is the speed of light in vacuum c (299 792 458 m/s). What can be changed in a lab is the speed of light in a material, which is given by c/n, where n is the refractive index (1.33 for water under normal conditions). So sure, you can reduce the speed of light in a lab. Just put a glass of water there.

For your comment on relative to the observer: The speed of light exactly is not dependent on the relative speed of the observer. That is what got us special relativity to begin with. You can read more here.

I thought it was clear I was being facetious... guess not, but I was.

[Deleted]

I thought it was clear I was being facetious... guess not, but I was.

My apologies for the misunderstanding. I still think that statements including "... have done this in a lab already" should be used with some modicum of care for the facts, as there is a lot of people that do not have a solid science background.

[Uzkin]

It is impossible not only according to current theories of physics but also according to observations.

Expecting some new physics theory to somehow enable speed-of-light travel for massive objects is akin to expecting some new physics theory to enable man to fly to moon unaided just by flapping one's arms vigorously.

[Deleted]

I think you mischaracterize Warp here by quite a bit. The idea of a warp drive is more similar to the creation of a direct wormhole and not so much to a hyperspace drive. You do not go to a different universe (not sure what that would even imply), you just compress the space in front of you, by "putting" large amounts of energy (and thus mass) in it that contracts it, pass through the contracted space and then let it expand again after you are through.

- - - Updated - - -



What about it? Things can move apart faster than the speed of light, this does not violate that there is no information transfer faster than light.

Inflation implies the value of c is variable

[klogaroth]

Even then, space is big. Really big,

[Kujako]

My apologies for the misunderstanding. I still think that statements including "... have done this in a lab already" should be used with some modicum of care for the facts, as there is a lot of people that do not have a solid science background.

Fair enough,

[Deleted]

It is impossible not only according to current theories of physics but also according to observations.

Expecting some new physics theory to somehow enable speed-of-light travel for massive objects is akin to expecting some new physics theory to enable man to fly to moon unaided just by flapping one's arms vigorously.

There are a number of theoretical work arounds but it would take infinite energy to accelerate any object/particle to exactly c in the current universe.

[Deleted]

Inflation implies the value of c is variable

In what way? Inflation means the expansion of the universe was faster than c, so that different parts of the universe became unable to interact after a certain time. How does this change the value of c?

[Shinra1]

I have FAITH that we can do this.

[Deleted]

In what way? Inflation means the expansion of the universe was faster than c, so that different parts of the universe became unable to interact after a certain time. How does this change the value of c?

Latest theorie(s) suggest c was infinite from the big bang through the end of inflation. Admittedly a short time.

Further resolution of mbr will hopefully give an answer to this.

Having said all that, inflation has never set well with me. X 10^60 In 10^ -30 seconds always sounds like magic.

[dadev]

Inflation implies the value of c is variable

Theories with variable c aim to replace cosmic inflation theory. Cosmic inflation does not assume or imply variable speed of light, as the theory is about deformation of space-time.

[Deleted]

Latest theorie(s) suggest c was infinite from the big bang through the end of inflation. Admittedly a short time.

Further resolution of mbr will hopefully give an answer to this.

Having said all that, inflation has never set well with me. X 10^60 In 10^ -30 seconds always sounds like magic.

It would really be helpful if you could combine such statements with a source for further reading.

[dadev]

Latest theorie(s) suggest c was infinite from the big bang through the end of inflation. Admittedly a short time.
Further resolution of mbr will hopefully give an answer to this.
Having said all that, inflation has never set well with me. X 10^60 In 10^ -30 seconds always sounds like magic.

There are theories sure, but they have far less merit than cosmic inflation. There's nothing in the observable universe which suggests that light could travel with different velocity in vacuum, in that case why would that be any different for past time? Does light get slower with time? This actually implies an aether theory, I hope you know what that means.
On the other hand, cosmic inflation is elegant in a way that it doesn't modify any property of particles in the universe, but only the shape of the universe. From observable data we already know that the shape of the universe is not uniform in localized regions. It's true that there's no indication that it's not uniform on large scale, but I'd take even partial evidence over no evidence at all (like for variable c).

[Elim Garak]

Light travels with different velocity in different environments. It's quite possible there's an environemnt in which it can go faster than in vacuum.

[dadev]

Light travels with different velocity in different environments. It's quite possible there's an environemnt in which it can go faster than in vacuum.

It's always slower in local scale. Otherwise it'll violate causality.

[Zethras]

No.

It takes too much energy to go even a significant fraction of the speed of light. Objects with mass can neither meet nor exceed the speed of light.

The only way we'll ever travel the stars is to warp space, which is more theoretically possible than breaking C, but still beyond our technological capabilities, and still requires understanding areas of physics that are still unknown.

- - - Updated - - -



There are plans to send microchips with lightsails, powered by a laser, to Alpha Centauri, but even that journey, a distance of 4.5 light years, is suggested to take a decade, and we have no idea how to slow down the light sail once it gets to Alpha Centauri to take pictures and transmit them back.

- - - Updated - - -



If we did travel at C, it'd still take ~100,000 years to cross the galaxy.

Then reduce the mass to 0.

[Serpha]

Who knows, but before we do we will have a jumpdrive of some sort.

[evogsr]

I didn't go through the whole thread but this is pretty interesting: https://en.wikipedia.org/wiki/Kardashev_scale

For the relevance this holds, we've got a long way to go (we'll never get there). It's fun stuff to think about though.

[Deleted]

There are theories sure, but they have far less merit than cosmic inflation. There's nothing in the observable universe which suggests that light could travel with different velocity in vacuum, in that case why would that be any different for past time? Does light get slower with time? This actually implies an aether theory, I hope you know what that means.
On the other hand, cosmic inflation is elegant in a way that it doesn't modify any property of particles in the universe, but only the shape of the universe. From observable data we already know that the shape of the universe is not uniform in localized regions. It's true that there's no indication that it's not uniform on large scale, but I'd take even partial evidence over no evidence at all (like for variable c).

There are some theories that are competing with inflation.

Also I know of one being formulated around compacted virtual particles. I'm not the author and it's not my area and the maths involved was truly incomprehensible but something to do with compacting down how light interacts with virtual particles.

Hard to type more on my phone sorry

- - - Updated - - -

There are theories sure, but they have far less merit than cosmic inflation. There's nothing in the observable universe which suggests that light could travel with different velocity in vacuum, in that case why would that be any different for past time? Does light get slower with time? This actually implies an aether theory, I hope you know what that means.
On the other hand, cosmic inflation is elegant in a way that it doesn't modify any property of particles in the universe, but only the shape of the universe. From observable data we already know that the shape of the universe is not uniform in localized regions. It's true that there's no indication that it's not uniform on large scale, but I'd take even partial evidence over no evidence at all (like for variable c).

We have results of light emitted from distant events arriving with slight delays based (It seems) on their energy.

- - - Updated - - -

Theories with variable c aim to replace cosmic inflation theory. Cosmic inflation does not assume or imply variable speed of light, as the theory is about deformation of space-time.

Points in that inflating spacetime 'moved' faster than c is currently measured at.

I realise this is not quite the same as particles moving faster than c.