Why not faster than light?

[kmarinas86]

<font color="yellow">That article points out that significant portions of the observed universe are receeding at superluminal speeds due to cosmological expansion.</font><br /><br />So that superluminal increase in distance is not due to velocity but that part of seperation increase caused by the expansion of space.<br /><br />In actuality, this does not violate relativity.<br /><br />Inflation is a function of mass density. The greater the mass density the less the inflation and less the expansion and a Big Crunch. Greater mass density means a tendency towards postive curvature. To my understanding, lesser mass density tends to more open curvature, exaggeration of stellar distances, and greater negative pressure.

 

[serak_the_preparer]

<i>I want to know why can't we go faster than light and why we couldn't in the future?</i><br /><br />Somewhere on this thread, you may have seen the sound barrier argument. It was once considered an insurmountable barrier, but humans managed to break through it. Still, even before humans had managed to go faster than sound, we knew of other things which did not acknowledge the sound barrier.<br /><br />One example: Light. We knew light moved faster than sound. So we knew there were things in nature which could exceed the speed of sound.<br /><br />Does anything in the universe move faster than light? Depending upon how one phrases the question and its answers, a qualified 'yes' can sometimes be produced. Still, in the case of the sound barrier, that question could garner a definite 'yes' where everyone accepted that, indeed, some things truly and indisputably move faster than sound.<br /><br />What - without dispute or qualification - moves faster than light?

 

[argosy]

What - without dispute or qualification - moves faster than light? <br />I'll tell you what...it's not a particle, not a wave...it's the human mind and imagination, and that alone is enough for me...I belive that, in the less or more distant future mankind will travel or at least communicate at the speeds greater than c...why? Don't know, but it's logical...I belive that every problem has its solution, less or more complicated. I just finished my first year of studying physics, and based on my observations, there's no known force in the universe that can stop human progress, except humans themselves...it will take time, but it will happen...<br />btw, what's with hawking's radiation? i know it's still speculation, but he suggested that some particles, trapped in black holes, could travel faster than light' Correct me if I'm wrong...

 

[labguy]

<blockquote><font class="small">In reply to:</font><hr /><p>btw, what's with hawking's radiation? i know it's still speculation, but he suggested that some particles, trapped in black holes, could travel faster than light' Correct me if I'm wrong...<p><hr /></p></p></blockquote>Hawking radiation deals only with what happens outside the event horizon (EH) and does not address anything that might happen inside the EH. There are other theories about events inside the EH, but all is speculation and nothing is known yet what is "inside" or even if singularities exist. A lot of physicists are backing away from the idea, or even a "need", for a singularity. Either way, HR is basically an effect involving photons and some particles outside the EH and doesn't include any faster-than-light effects.<br /><br />A good deal about HR, and even more about black holes in general, can be found at these sites:<br /><br />http://www.physics.hmc.edu/student_projects/astro62/hawking_radiation/radiation.html<br /><br />http://casa.colorado.edu/~ajsh/hawk.html<br /><br />http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/hawking.html<br /><br />http://library.thinkquest.org/C007571/english/advance/english.htm?tqskip1=1&tqtime=0602<br /><br />http://superstringtheory.com/blackh/blackh3.html<br /><br />http://www.bbc.co.uk/dna/h2g2/alabaster/A568514<br /><br />http://relativity.li

 

[argosy]

-A lot of physicists are backing away from the idea, or even a "need", for a singularity-<br />intresting. I may be wrong, since for now i have only dealt with mechanics and some simple SR, but how would you then describe the state of the universe in the early beggining-i mean just before the big bang, when there was(or it was supposed to be) infinite density of matter(energy)-i guees that was a singularity of some kind?

 

[serak_the_preparer]

<i>I'll tell you what...it's not a particle, not a wave...it's the human mind and imagination, and that alone is enough for me...</i><br /><br />Very poetic. I'd like to agree, but...<br /><br /><i>I belive that, in the less or more distant future mankind will travel or at least communicate at the speeds greater than c...why? Don't know, but it's logical...I belive that every problem has its solution, less or more complicated.</i><br /><br />Both communication and travel at speeds in excess of <i>c</i> pose serious problems for causality and the fundamental underpinnings of physics. 'Can you arrive at your destination before you've departed?' kinds of problems. There just may be some loopholes which allow for a means of cheating and getting around this limitation, at least in the case of communication.<br /><br />It might be possible, for instance, to transmit information so that it is received faster than light, though there might then prove to be delays in reading out the information which are intrinsic to the process. End result: The information does not have an opportunity to affect observers and events at a rate exceeding the speed of light.<br /><br />Does every problem have a solution? No, not always. What happens when the unstoppable force strikes the immovable wall? There sometimes are mutually exclusive conditions which prevail in this universe.<br /><br /><i>I just finished my first year of studying physics, and based on my observations, there's no known force in the universe that can stop human progress, except humans themselves...it will take time, but it will happen...</i><br /><br />If you continue your study of physics, your mindset may undergo some adjustment. Living in a universe of physical laws, where physical constants and limits exist, means some things are possible, while others aren't.<br /><br /><i>that can stop human progress, except humans themselves...it will take time, but it will happen... <br />btw, what's with hawking's radiation? i know it's</i>

 

[argosy]

I agree with most of what you said in you post. True, my mind will probably undergo a change, and i'm very happy and excited because of it...<br />---Both communication and travel at speeds in excess of c pose serious problems for causality and the fundamental underpinnings of physics. 'Can you arrive at your destination before you've departed?' kinds of problems. There just may be some loopholes which allow for a means of cheating and getting around this limitation, at least in the case of communication. ---<br />those are current fundamentals of physics(causality)...the best mankind has currently to offer...they may/will change, but no matter what, there's still a bunch of solutions(and exotic, sure, but imagine leonardo da vinci showing his"plane" to some scientists of his era...i bet the conversation would be like this we are having) we can work on(warping, wormholes, hyperspace, extra dimensions...the list goes on forever)...as i said, i'm almost certain we'll do it.<br />One more thing. We are probably not the only intelligent life form working on this problem. Somebody has to find the solution, wright, ? <br />---Does every problem have a solution? No, not always. What happens when the unstoppable force strikes the immovable wall? There sometimes are mutually exclusive conditions which prevail in this universe. ---<br />the "can god create a rock so heavy he cannot lift" debates are...well, idiotic(no offense to you). I was more thinking of an engineering problem, not mind games and logical/ilogical judgments(i had my fair share of philosophy and logic). I'll change to"most problems have a solution"(hope this one does)<br />---Living in a universe of physical laws, where physical constants and limits exist, means some things are possible, while others aren't---<br />you sound like my physics teacher...

 

[Saiph]

MBA,<br /><br />I'm quite familiar with the quantum tunneling loophole. But theres something to point out...<br /><br />Those quantum effects rely upon the non-localized nature of particles, as they are waves (or can be considered such) you can't really say the particle is here, or there, until you find it. Until then you can merely say how probable it is to be found in those locations.<br /><br />The tunneling experiment never beats the speed of light by a LOT. Instead its enough that several of the professors I've talked to, think it may merely be the tunneling shifts the wavepacket.<br /><br />Normally the wave packet (probability) is shaped like a bell curve, you tend not to detect the leading or trailing edges, but you usually get the middle section.<br /><br />If in the process of tunneling, that packet gets "front loaded" you'll detect it sooner (as you'll tend to detect the front end) on the sensor after the tunneling...this may account for the slight boost in "speed".<br /><br />Furthermore, this effect cannot be used for macroscopic objects nor can it be used over long distances (tunneling becomes harder the further you have to go). <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>