Einsteins Relativity at risk

[docm]

IF they're right the speed of light in a vacuum, C, may not be a constant but depend on its energy.<br /><br />Scientific American link....<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p><b>Hints of a breakdown of relativity theory?</b><br /><br />The MAGIC gamma-ray telescope team has just released an eye-popping preprint (following up earlier work) describing a search for an observational hint of quantum gravity. What they've seen is that higher-energy gamma rays from an extragalactic flare arrive later than lower-energy ones. Is this because they travel through space a little bit slower, contrary to one of the postulates underlying Einstein's special theory of relativity -- namely, that radiation travels through the vacuum at the same speed no matter what?<br /><br />The team studied two gamma-ray flares in mid-2005 from the black hole at the heart of the galaxy Markarian 501. They compared gammas in two energy ranges, from 1.2 to 10 tera-electron-volts (TeV) and from 0.25 to 0.6 TeV. The first group arrived on Earth four minutes later than the second. One team member, physicist John Ellis of CERN, says: "The significance of the time lag is above 95%, and the magnitude of the effect is beyond the sensitivity of previous experiments."<br /><br />Either the high-energy gammas were released later (because of how they were generated) or they propagated more slowly. The team ruled out the most obvious conventional effect, but will have to do more to prove that new physics is at work -- this is one of those "extraordinary claims require extraordinary evidence" situations. But if the high-energy gammas really did lose the cosmic race, we're talking Big Discovery. It could be a way to constrain string theory, loop quantum gravity, and other bleeding-edge theories.<br /> /><br />The basic picture is that high energies</p></blockquote> <div class="Discussion_UserSignature"> </div>

 

[vogon13]

Doesn't really sound like relativity is at risk.<br /><br />Just a bit of a tweak in the range of 1 tera (!!!!!!!!!!!!!!!!!!!!!!!!!!!) electron volts.<br /><br /><br />4 minutes in 500,000,000 years . . . <br /><br /><br /><br /><br /><br /> . . . .pish posh.<br /><br /><br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[jaxtraw]

I'm sorry, but if we're going to declare relativity at risk, I want a darned site better than a 95% confidence level. People treat 95% like some kind of holy scripture, how often do you read "scientists say a 95% confidence level mean it's true"?<br /><br />Well, it's a 1 in 20 chance it's wrong, and that's if you've even got a real result rather than some enticing noise. So, I shall continue to stick with Einstein for a while, until somebody's got something a bit more solid, frankly <img src="/images/icons/smile.gif" /><br /><br />There's just too much declaring victory on the basis of single questionable results these days, mumble mumble grumble.

 

[derekmcd]

They kinda lost me when they showed interest that the 'bloggers' were weighing in.<br /><br />Let's wait until they verify the result and can reproduce them. Otherwise, I see it a nothing more the a sensationalized headline.<br /><br />This quote is from the article, but the article doesn't say from whom the quote is attributed to:<br /><br />"<i>I need to look into this a bit more, but I just wanted to get the news out there for people to mull.</i>"<br /><br />Let's not bust Einstein in the chops yet <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[heyscottie]

Oh, it's definitely a sensationalized headline, but it is intriguing nonetheless. I wonder how much work has been done devising experiments to test light velocities in a highly precise way across the energy scale? Unfortunately, an effect as small as what was reported would probably be nearly impossible to demonstrate in a Terrestrial lab -- I calculate that a similar effect, if it scales linearly, as seen from the opposite side of earth's orbit, would translate to about 260fs of relative delay. Maybe we could measure femtoseconds of delay across the earth's orbit, but it would be a pretty expensive experiment, that's for sure!

 

[heyscottie]

Oh, and by the way, Einstein was NOT the one who said that light always moves at c. That was established before him. He used that fact as one of the two major building blocks for deducing Special Relativity. In other words, it was in input for Einstein, not an output.

 

[kelvinzero]

I realise this is a very preliminary result, but could this be explained by space not being truely empty? I think the slowing of light through materials is wavelength dependent just as the refraction is wavelength dependent.

 

[heyscottie]

In fact, refraction occurs precisely BECAUSE light slows in a medium, and the slowing is wavelength dependent, as you said.<br /><br />I would hope that effects like this, if any, would have been taken into account before publishing any paper, even is Scientific American, but you never know...

 

[derekmcd]

I think this statement from the article:<br /><br />"<i>The team ruled out the most obvious conventional effect...</i>"<br /><br />is related to photons traveling through a medium. I'm just guessing, but I believe that would be the first thing they eliminate as it would likely be the primary culprit for this a phenomena like this. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[vogon13]

Interstellar gas and dust would be part of the medium.<br /><br />The CBR is another.<br /><br /><br />That there might be some (weird) interaction at or above 1 peta volt for gamma rays and CBR wouldn't be too big a surprise to me . . <br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[emperor_of_localgroup]

Couple of things I like to point out. Electromagnetic spectrum goes from 0Hz to infinity Hz. Our technology until recently couldn't even go into GHz . Thanks to cell phone tech. The range of frequencies we are using can be comapred to a few drops of water in the Atlantic ocean. A huge amount of frequency range is still out of our reach. We have no idea what are happening in those unaccessible frequencies. What drives me crazy is we are already talking about 'Theory of Everything'.<br /><br />Now, if anyone wants to blame interstelalr dust for this velocity discrepancy, fine, but then you have to give up redshift. Get ready to open a can of redshift worms. <div class="Discussion_UserSignature"> <font size="2" color="#ff0000"><strong>Earth is Boring</strong></font> </div>

 

[heyscottie]

Please explain to me why we would have to give up redshift.<br /><br />By the way, we've been running GHz for a VERY long time. And visible light, which we've been able to produce and receive for MUCH longer, is around 500 THz.

 

[emperor_of_localgroup]

No, I didn't mean anything against Doppler. I am a bit skeptical about relying too much on redshift in astronomical measurements. And now, if cosmic dust can alter speed of electromagnetic waves, they can also do a good job on the wavelengths. There are too many unknowns on the way from here to billions of light year away. Unfortunately we have very few tools (theory and tech) to explain things we see around us, that's why we have to rely on available theories.<br /><br />Yes, I did forget the visible part of the spectrum, but even then it comes up to 10¹⁵Hz. What about the remaining 10¹⁶Hz to 10^100000..Hz? It's mind boggling if we sit down and think about exactly how much we know and how much we still are incapable of knowing.<br /><br />Don't get disappointed, I guess that's how (slow) we humans have to discover the truth. <div class="Discussion_UserSignature"> <font size="2" color="#ff0000"><strong>Earth is Boring</strong></font> </div>

 

[heyscottie]

Okay, it seems like you are saying "if we're not sure about velocities, we're not sure about ANYTHING, including wavelengths." I suppose that's a fair point to make, but I'll say that even assuming that propogation speed is altered by dust or some previously undiscovered effect of spacetime or quantum gravity, it has no direct bearing on frequency shifts. Speed changes do not imply frequency changes or tired light or anything like it.