# Hypothetical way to travel faster than light, but not technically exceed lightspeed

1. Feb 6, 2012

### knicely

From what I understand, space (not matter) can expand at a speed faster than that of light, and when it does, it goes in all directions. Would it be possible to create a controlled expansion of space behind a vehicle along a single path, like a corridor, that would change your position in space technically faster than light?
And a follow up question, what is believed to cause the expansion of space?

2. Feb 6, 2012

### HallsofIvy

Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

Hmm, that way, you would be moving away from your starting point faster than c, but you would NOT be approaching your end point any faster! You would just be making the distance between start and end greater.

3. Feb 6, 2012

Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

I gather you mean the warp drive or Alcubierre drive involving space itself transporting the ship along with it at FTL speed to a predetermined destination. Well, it would be nice if it were as easy as the Star Trek episodes make it seem. Unfortunately the obstacles that such a method of travel would have to overcome are so daunting as to make it seem totally impossible not only with current technology but with any technology we can presently realistically envision.

For example one method requires preparing the trajectory for the ship beforehand. Obviously such preparation demands FTL capabilities. Other problems involve the inability of the crew to control the ship. Still others involve the application of mind-boggling impossible energies required to manipulate the fabric of space that way. The article below discusses these and others.

The Glen research center site has an article about what it claims to be the general scientifically-derived consensus on the FTL idea based on warp drive.

Last edited: Feb 6, 2012
4. Feb 6, 2012

### cristo

Staff Emeritus
Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

You mean the expansion of the universe, or the accelerated expansion of the universe that we measure at the current epoch? If the former, then it's essentially an initial condition of the big bang models; the latter is attributed to an unknown called 'dark energy'. This could either be some mysterious fluid with negative pressure, or require a modification of general relativity on the relevant scales.

5. Feb 6, 2012

### Dr_Morbius

Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

This universe sucks. We can't go faster than light. All we can hope for is to build a race of robots similar to the ones in Asimov's robot stories that would take our place and explore the galaxy for us.

6. Feb 6, 2012

### Drakkith

Staff Emeritus
Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

Perhaps. But maybe it's that exact limitation that has kept any aliens from invading the planet already!

7. Feb 6, 2012

### e^(i Pi)+1=0

Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

We will probably be that race in a few hundred years.

8. Feb 7, 2012

### dpa

Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

well if you love fiction, who knows we ourselves are robots of more intelligent creatures.

9. Feb 7, 2012

### Cosmo Novice

Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

Arthur C Clarke once said: "A sufficiently advanced technology is indistinguishable from magic"

If such limitations did not exist for another race - (they had overcome the seemingly impossible hurdles) then I dont see why they would invade us both from a practical and moral perspective.

In terms of physical materials there are much more abundant and easier invaded places. The recent abysmal Battle:LA was a terrible premise - the aliens invaded Earth for our water and seemingly ignored every other source of water in our solar system!

Then again I like the idea in the Day the Earth Stood Still where it is the life sustaining planet that is the resource.

10. Feb 7, 2012

### Ryan_m_b

Staff Emeritus
Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

Interesting premise, shame about everything else in that film. The only thing these supposedly magically advanced aliens could think of was total extermination even though they value life and have the ability to mystically change animal behaviour in order to make them come into the "arcs." Though I suppose a story where aliens give us the technology to live a totally eco-friendly existence and gently dismantle our weapons and current industries with their swarm wouldn't be such a sellable idea.

11. Feb 7, 2012

### Cosmo Novice

Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

A few really nice premises in that film; its just a shame its such a bad remake; the idea of aliens growing into human bodies and becoming more human was, IMO, a nice idea.

I think in honesty looking at the options then destruction from their perspective would be the most efficient and humane thing to do - but then we are judging through our own mores and values and whose to say that has any relevance to the alien view. (Maybe in fact it was the humen side of Klaatu that wanted to destroy!?) Anyway the original and lesser known film was actually a lot better!

I think if a magically advance alien race was to come down and give us answers to energy problems/global warming, hunger, immunity to disease, then how much more dangerous would the human race become - its like giving a child magical powers he has little comprehension of; at least thats how I see it.

12. Feb 7, 2012

### knicely

Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

HallsofIvy : I see what you mean. If you were to aim directly at your destination and cause space to expand, it would be pointless. Everything along this hypothetical corridor would be pushed apart. My thought is to aim to the side of your destination (and not at anything important behind you). That way, as space expanded and 'propelled' you forward, the object you're trying to reach wouldn't be kept the same distance away.

Radrook : I have never heard of an Alcubierre drive before, but it sounds fairly similar to my thought. Thank you

cristo : thank you for the info. That clarifies some stuff for me.

Pretty much with this idea, I was just trying to think of a way to technically move faster than light without actually moving faster than light and breaking the laws of physics, like a work around.

13. Feb 7, 2012

### Ryan_m_b

Staff Emeritus
Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

You might also be interested to read about NASA's Breakthrough Propulsion Program. Part of the problem in the ideas proposed by the BPP is that they are based on hugely speculative premises such as the ability to manipulate the gravitational constant, to acquire and manipulate negative mass or to develop superluminal signalling none of which is indicated to be possible (and if it were would severely undermine our understanding of the universe, not to mention introduce time travel).

Last edited: Feb 7, 2012
14. Feb 7, 2012

### LKD_

Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

Well if I read right, this is conceivably possible: http://www.guardian.co.uk/science/2011/sep/22/faster-than-light-particles-neutrinos

If you might somehow patiently manage to line up a long string black holes, using slingshots, that "might" be able to get you to reach the speed of gravity depending on the set-up; which is supposed to be the same as light. Giant qualifier quotes have been placed purposely. :D

Last edited: Feb 7, 2012
15. Feb 7, 2012

### cristo

Staff Emeritus
Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

This thread's gone from inquisitive to speculative, therefore no longer adheres to PF rules.

16. Feb 7, 2012

### Ryan_m_b

Staff Emeritus
Re: Hypothetical way to travel faster than light, but not technically exceed lightspe

I know the thread is locked but just for the record the neutrino result is yet to be confirmed https://www.physicsforums.com/showthread.php?t=532620 and no matter what you do an object with mass cannot reach the speed of light.