Faster Than Light Travel

[maccy]

I've got into a discussion about the relationship between science and science-fiction (it's at forums.scifi.com/index.php?showtopic=2250827 if you're curoius, I can't post links yet).

Part of my argument was that Faster Than Light Travel is not based on actual science as the Theory of Relativity makes it impossible.

This is one of the reponses I got:

please read and understand Einstein's papers on general and special relativity and in them nowhere does it say that that nothing can travel faster than the speed of light that is complete and utter ***** but it does say that thraveling faster than light is difficult due to the affect that the closer you get to C (the speed of light) the more energy goes into increasing your mass instead of increasing your velocity
and it also states that the faster you go the slower time travels for you compeared to someone at rest
but as i have already said it doesn't say you can't travel faster than the speed of light

My reply was copied from a post on the Conspiracy Theory forum (forums.randi.org/showthread.php?postid=2021696#post2021696)

OK I was basing my statement on this:

e=mc^2 is the rest energy, applying to objects with no momentum.

Consult en.wikipedia.org/wiki/E%3Dmc%C2%B2


You divide the answer by sqrt(1-v^2/c^2) for objects in motion. In other words, for non-zero mass, traveling at the speed of light (v=c), the equation reduces to:

E=mc^2 / 0

Source (link to JREF forum, as above).

Which implies to me that for an object with mass, acceleration to the speed of light requires infinite energy. Therefore, objects with mass cannot accelerate to the speed of light, much less beyond it.

The reply I got was this:

i read through that link you posted and they are right, to accelerate matter to the speed of light you would need infinite energy because the faster matter gets the more mass increases there for the more energy is required to keep accelerating the matter untill the matter reachers infinite mass which inturn require infinite energy to accelerate it
but we are talking about technology traveling at the speed of light and in physics there is no reason why you can't reduce the mass of matter there for avoiding the requirement for infinite energy
or you can by-pass the problem all together and not move but instead move the universe around you which still doesn't back any rules

Does this make any sense at all, in terms of current science? Both points seem nonsensical to me.

Also, is there any plausible hypothesis (eg worm holes, warp drives) that suggests that maybe faster than light travel may be possible?

I've invited the person who made these posts over here to join the discussion, if they feel so inclined.

I didn't want to bog the other discussion down in science, and I'm interested in getting the views of people with a good understanding of Einstein and relativity (which I don't have but would like to learn more).

 

[Dave1001]

Good questions. I think you're right, shrinking down matter doesn't seem to make sense because I think the point is any matter of any mass would take infinite energy to accelerate it to the speed of light.

I don't know about moving the universe around you or how that would be done -I've heard it proposed but don't recall the proposed mechanism.

No idea about wormholes.

I'm not well read beyond a generally educated layperson on these topics

 

[jmercer]

There are others who can answer you with much more detail, but nothing can go faster than light. I'll let others describe why.

Worm-holes (in terms of what you've asked about) may exist, but they would probably only exist at planck size. A large one would probably be so unstable as to be unusable; plus the forces in a large wormhole would probably have undesirable effects on matter passing into and through it... if the very act of sending matter into it wouldn't simply cause it to collapse, that is.

In theory, wormholes don't provide FTL travel, anyway; what they do is supposedly provide a "short-cut" between points in our three-dimensional universe. Think of putting two dots on a piece of paper, one at the bottom and one at the top. Center them on the page exactly 1 inch from the edge of the bottom and top.

Now, measure the distance between the two dots. That can represent the distance between two points in a two-dimensional "flatland" universe.

Now, fold the paper so the two dots touch. The distance between them is now zero because they're touching in a new dimension - the third dimension. If you went from the first dot to the second dot, it would take no time at all because you've bypassed the distance in flatland by going through a "wormhole" in the flatlander universe.

Those two dots represent each end of a wormhole; so it's not that you're traveling faster than light so much as you've found a shortcut.

If you want to understand more on the challenges of wormholes and travel, pick up Carl Sagan's book "First Contact". It's a good read and the book outlines some of the challenges involved with manipulating such a thing.

BTW, it is also just as possible that a wormhole would never reconnect in our universe, but instead would take you to another universe on a one-way trip.

No comment on warp-drives other than to say they're even more speculative than wormholes.

 

[Dark Jaguar]

Well sure, if you reduce the mass being moved to ZERO then hey, there you go, but you can't get faster.

And move the REST of the universe? Did that guy watch Futurama before he responded or something? That's the same problem multiplied by the MASS OF THE UNIVERSE (minus your ship). How are you going to move the rest of the universe exactly? A lot of really strong chains?

So I'd say his response is pretty much silly. Thing is, it's sci-fi. It doesn't HAVE to be accurate.

As for worm holes, I dunno, you'd have to ask the experts around here. I would think that if you just cut a hole in space/time to go somewhere, you can get there a lot faster than light taking the "long way" would, but I wouldn't call that "faster than light travel", just a shortcut. Might as well say the guy walking next to a maze is "faster than" the guy who has to run through the whole maze, even if the guy in the maze was running and the guy outside it was strolling along.

 

[fuelair]

There are others who can answer you with much more detail, but nothing can go faster than light. I'll let others describe why.

Worm-holes (in terms of what you've asked about) may exist, but they would probably only exist at planck size. A large one would probably be so unstable as to be unusable; plus the forces in a large wormhole would probably have undesirable effects on matter passing into and through it... if the very act of sending matter into it wouldn't simply cause it to collapse, that is.

In theory, wormholes don't provide FTL travel, anyway; what they do is supposedly provide a "short-cut" between points in our three-dimensional universe. Think of putting two dots on a piece of paper, one at the bottom and one at the top. Center them on the page exactly 1 inch from the edge of the bottom and top.

Now, measure the distance between the two dots. That can represent the distance between two points in a two-dimensional "flatland" universe.

Now, fold the paper so the two dots touch. The distance between them is now zero because they're touching in a new dimension - the third dimension. If you went from the first dot to the second dot, it would take no time at all because you've bypassed the distance in flatland by going through a "wormhole" in the flatlander universe.

Those two dots represent each end of a wormhole; so it's not that you're traveling faster than light so much as you've found a shortcut.

If you want to understand more on the challenges of wormholes and travel, pick up Carl Sagan's book "First Contact". It's a good read and the book outlines some of the challenges involved with manipulating such a thing.

BTW, it is also just as possible that a wormhole would never reconnect in our universe, but instead would take you to another universe on a one-way trip.

No comment on warp-drives other than to say they're even more speculative than wormholes.

Last time I played a bit with this, the problem with the wormhole idea was that the material going in was no longer in the form it started as (living for one thing). Matter in -becomes just matter and comes out as bits of matter on the other end (atomic particles pretty much).

 

[scotth]

With our current understand of physics, there is no chance of developing a technology that will relieve matter of its mass. Actually, there is. A nuclear weapon converts a fraction of its mass into energy. A matter anti-matter reaction would be a perfect example. But, I don't think you want that happening to you and your spacecraft.

 

[ponderingturtle]

One way to put what reletivity says(and observations hold to) is this

1. Effects can not precede causes
2. The laws of physics are the same for everyone no mater their innertial reference frame
3. Something can travel faster than light

Pick two.

One is generaly taken to be logicaly nonsensical, as if you have something travel faster than light to one observer there is a seperate observer who saw it arive before it left and could concievably interact with the sending individual before anything was sent.

So you really need to pick two of those, because if 3 is true, you can not have both 1 and 2.

 

[Jeff Corey]

"OY! CAPTAIN! The antimatter doesn't matter anymore. Someone snorted all the dilithium crystals."

 

[Ziggurat]

One way to put what reletivity says(and observations hold to) is this

1. Effects can not precede causes
2. The laws of physics are the same for everyone no mater their innertial reference frame
3. Something can travel faster than light

Pick two.

Yup, that's about the size of it.

For purposes of science fiction, the one you want to throw out is number 2. This doesn't actually require throwing out relativity, but it would require that relativity not apply to some new physical effects which are at present unknown (in other words, there must be some prefered frame of reference which can be detected locally). That is, of course, very much fiction, but it wouldn't require any internal inconsistencies, which is really what you want for sci-fi scenarios.

 

[Soapy Sam]

"Faster than light" is an oxymoron, like "military intelligence". Relativity says a material object cannot travel at c. It does not say nothing can go faster than light. It says there is no such velocity, just as an object cannot have a temperature below absolute zero, because there is no such temperature.

The difference between science and science fiction, is fiction.

For a good story to work, it may require FTL. If it's a good story, it can require Leprechauns with matter transmitters for all I care.

Willing suspension of disbelief.

 

[Hellbound]

The only remotely feasible method for FTL is more like finding short-cuts than actual FTL. There is a possibility (based solely on mathematical manipulations of the equations involved in relevent theories) to create wormholes. This could allow for effective FTL travel not by actually travelling FTL, but by shortening the distance between two points. However, these solutions still run into the problem of requiring things that are physically impossible or completely unknown: such as an infinitely long, cylindrical, rotationg black hole, a toroidal rotating black hole, or "exotic matter", matter that has a negative energy density (and thus a negative mass).

 

[maccy]

Thanks for the replies people. As the discussion has included some posts about Science Fiction not needing to be scientific I'll give you a quick run down on the discussion that lead me starting this thread (full discussion is on the sci-fi channel doctor who board forums.scifi.com/index.php?showtopic=2250827)

It starts with a quote about Science Fiction from Russell T Davies (the man who brought back Doctor Who in 2005) in an article in The Times (entertainment.timesonline.co.uk/article/0,,14934-2407543,00.html)

I have always loved science fiction. As a child, I absolutely adored Doctor Who. It’s a passion that’s never left me. But I understand why there’s still a taboo around it. I’ve never liked fantasy. I get very put off by elves and dwarves and any sort of Middle-earth fantasy land. I can’t stand The Lord of the Rings. Science fiction, to me, is quite different. More rational, closer to the real world. My homemade definition of science fiction is that it deals in rational, scientific rules, rather than fantasy’s world of magic. That’s my distinction.

If there was a Doctor Who story in which magic occurred, I simply wouldn’t allow it. I’d rather it be alien technology than magic. Because I always want there to be some ordinariness in there; some mundanity with the extraordinary.

The argument of one of the posters was that Russell is beign hypocritical in criticising fantasy here because what he is writing is Science Fantasy and not Science Fiction - beacuse Science Fiction is based on "Actual Science".

My argument is that very little of what is called Science Fiction is based on actual science but that the important thing is that world portrayed is philosopnically materialistic and rational (ie there is no magic) - which I think agrees with what Russell is saying.

As part of this, I aked for an example of "proper" Science Fiction on TV or in Film. Among the replies I was given: Star Trek. This is what started the argument about FTL travel.

The more that these people who are convinced about the distinction between Science Fiction and Science Fantasy post about science the more I'm convinced that their idea of Science Fiction is something that has fooled them into thinking it is real science. Here is part of the last rebuttal I received:

I would make one more comment about this. Practically all of modern day physics is based entirely on theories that can only be proven by math (and not even necessarily then). So your saying that just because it hasn't been "proven" makes it fantasy is clearly erroneous, and also shows you lack an understanding of the most basic principles of science (Hypothesis, disproval of hypothesis, if Hypothesis cannot be disproved then it is considered scientific fact until something does disprove it).

I've encouraged them to come over to this thread to discuss things further.

 

[Godmode]

AT this point, let's just try to get travel UP to light speed. Then I'm sure someone will learn how to break the barrier, just like they did with the speed of sound.

 

[maccy]

AT this point, let's just try to get travel UP to light speed. Then I'm sure someone will learn how to break the barrier, just like they did with the speed of sound.

There's no point. Travelling at light speed requires infininte energy. Travelling at near light speed requires unfeasibly vast amounts of energy.

 

[maccy]

Regarding wormholes, I only have the vaguest undertasnding of space-time and I cannot really understand how a clear metaphor involing folding a sheet of paper can be applied to space-time.

I understans that this is only a mathematical hypothesis, but can anybody suggest a good place to start for getting a hendle on the idea of wormholes?

 

[Mashuna]

AT this point, let's just try to get travel UP to light speed. Then I'm sure someone will learn how to break the barrier, just like they did with the speed of sound.

I don't think the sound barrier was ever really seen as an upper limit on speed though. People just went a bit faster - there was no special breakthrough required. The crack of a whip is due to it exceeding the speed of sound.

The speed of light is rather different to that

 

[maccy]

Bullets travel faster than the speed of sound as well.

Actually, that's quite a good visualisation of the problems with concept of FTL: can you imagine using a gun where you saw the target being hit before you pulled the trigger? Before you picked up the gun, even?

 

[ponderingturtle]

The argument of one of the posters was that Russell is beign hypocritical in criticising fantasy here because what he is writing is Science Fantasy and not Science Fiction - beacuse Science Fiction is based on "Actual Science".

My argument is that very little of what is called Science Fiction is based on actual science but that the important thing is that world portrayed is philosopnically materialistic and rational (ie there is no magic) - which I think agrees with what Russell is saying.
.

If they are not breaking things down into hard sf, soft SF and space opera to name a few then they are not being very precise with scifi.

I have had debates about how invasive scifi in relative to fantasy, and it seems that scifi is much more invasive as adding a little scifi element makes a story scifi while adding in a bunch of fantasy elements does not make the story fantasy.

 

[ponderingturtle]

I don't think the sound barrier was ever really seen as an upper limit on speed though. People just went a bit faster - there was no special breakthrough required. The crack of a whip is due to it exceeding the speed of sound.

The speed of light is rather different to that

Well there where theories about how something could be shaped and survive going faster than sound, but really bullets did it all the time, so it was known to be possible for as long as it was known to exist

 

[drkitten]

"Faster than light" is an oxymoron, like "military intelligence". Relativity says a material object cannot travel at c. It does not say nothing can go faster than light. It says there is no such velocity,

Er, no. FIrst of all,. there is definitely such velocity; we've even measured "things" (broadly defined) moving at faster than the speed of light.

And there's nothing wrong with a material object travelling faster than the speed of light. Such objects are called tachyons and they're a well-accepted concept in physics. The problem is that such objects can never travel slower than the speed of light; the c barrier cannot be crossed by any method.