Peanuckle on 24/9/2011 at 06:55
So assuming that everything pans out and we get FTL that messes with the order of events, what kind of crazy hijinks do you think people will get up to?
Cloning ourselves by arriving before we left is an often cited one. What can you guys think of?
nicked on 24/9/2011 at 19:38
So, if travelling faster than light is equivalent to time travel, surely the distance back in time would vary depending on how fast one travelled beyond light speed. So, if someone sets out from Earth to a new planet in their Mark 1 space craft that goes a tiny bit faster than the speed of light, and arrives a couple of years later at the planet, could they theoretically find the long-dead remains of the colony founded by the guys who set off a year later but travelled 200 times the speed of light?
Can someone sciencey explain whether this is bollocks or not?
Also, how the hell do I wrap my head around the concept that a sub-luminal journey that appears to take thousands of years from Earth might only be perceived as a subjective few years to the people on the spaceship?
SubJeff on 24/9/2011 at 19:43
Quote:
Cloning ourselves by arriving before we left is an often cited one. What can you guys think of?
This. This is all. 1 more of me, or 9? That's the real question.
Al_B on 24/9/2011 at 20:18
Quote Posted by nicked
Also, how the hell do I wrap my head around the concept that a sub-luminal journey that appears to take thousands of years from Earth might only be perceived as a subjective few years to the people on the spaceship?
I'm really, really not the person to answer this as I've had major issues wrapping my mind around it too. As far as I can tell, it all boils down to whether the speed of light is the same regardless of how fast you're travelling. i.e. you can be travelling at half (or more) the speed of light and light will still stream away from (or towards) you at the same speed. It's completely counter-intuitive but appears to hold up in scientific measurements.
If this is true then the faster you travel then to someone watching you it would appear that your local time was slowing down. For example, if you were travelling in a circle around someone at very high speed (very close to the speed of light) if you were to turn on a torch then from your perspective the photons would stream away from you at the speed of light. However, to the observer the photons would move away from you at a relatively slow speed since you're travelling at almost the same speed they are.
Again, I may be off the wall with this one, but that's how I understand relativity theory and happy if someone else with more knowledge can chip in.
demagogue on 24/9/2011 at 23:47
That's what I understood from what I've read too.
As for the time bending stuff, I don't know for sure either, but IIRC it's something like, well one way to put it is: time & space get compressed for fast moving things. So if you were traveling to the moon, the faster you moved (i.e., from your perspective, the faster the moon is racing towards you), the literally closer the moon gets to you because the space is getting compressed, and the less time it takes to get there because time is compressed. Space-time is compressed. When you get to c, the space-time is compressed at its limit, so you arrive at the moon the instant you leave because you don't travel through any space or any time (from your perspective; to an outside observer, it'd take you however long c*distance is), or it's just one click of time, the leaving event and the arriving event, without any clicks in between (so there's no slack to "make up"; if you buy the discrete space-time bit anyway). So... if you were going *faster* than light, then in some respect, from your perspective, you'd have to "arrive" at the moon "before" you left as far as the math is concerned. So either it's a false alarm, something very weird is going on and time & causality aren't what we think it is, or the math just breaks down. If this holds up, my worthless bet is that the math breaks down, causation is still preserved (so you don't arrive before you left; there's still some ordered click of cause & effect in some respect), but that there may be some weird non-local connection like quantum physics already seems to have, and time & space don't behave like we expect in connecting cause & effect. This is coming from a popular science book junkie though, haha, still pretty worthless.
Or, in sum:
Quote:
"We don't allow faster-than-light neutrinos in here", said the bartender. A neutrino walks into a bar.
Tocky on 25/9/2011 at 01:04
Quote Posted by demagogue
Seriously, I made the whole thing up. I'd be surprised if I stumbled into saying a single thing close to proper.
Does this mean I can't tape a large poster of you on dorm room walls? It sounded good to me.
SD on 25/9/2011 at 21:15
Quote Posted by Subjective Effect
This. This is all. 1 more of me, or 9? That's the real question.
However many you need for an effective daisy chain, I suppose.
june gloom on 25/9/2011 at 21:26
Operation Keep Straight Face At Work: MISSION FAILED
Pyrian on 27/9/2011 at 22:51
Quote Posted by heywood
If we can reproduce this result and confirm the ability to send neutrinos from one point to another faster than light, then we'll have to remodel our understanding in the biggest way since QM. I think it would mean that either the laws of physics are not the same for all observers, or the principle of cause & effect is wrong.
Perhaps the simplest explanation is that the speed of light in a vacuum is actually slightly less than the "true" c. Perhaps the light interacts with the vacuum in a way that slows it down a tiny amount.
blubbafat on 27/9/2011 at 22:59
Has anyone told Hawkwind?
