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Science

Light Slowed Down To 127 mph 53

Posted by timothy from the son-do-you-know-how-fast-you-were-going dept.
Makarand writes "Although slowing down a light beam is as simple as passing it through a window pane, slowing down light dramatically has always involved extremely low temperatures and rooms full of complex equipment. A new small device developed at the University of Rochester can now slow light down to 127 mph without using the room-filling mechanisms previously required. The new technique uses a laser beam to create a hole in the absorption spectrum of a common ruby at room temperatures that can allow a second laser beam, with a frequency slightly different than the first laser, to shine through that hole at a greatly reduced speed. This light slowing device might find applications in the telecommunications industry."
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Light Slowed Down To 127 mph More

Light Slowed Down To 127 mph

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  • Why not... (Score:3, Funny)

    by C0LDFusion ( 541865 ) on Monday March 31, 2003 @11:46PM (#5635805) Journal
    ...work on getting us to light speed, rather than getting light to our speed?

  • On Another Note (Score:3, Informative)

    by Tolchz ( 19162 ) on Monday March 31, 2003 @11:52PM (#5635842) Homepage
    Light travels even slower at 38mph
    http://slashdot.org/articles/99/02/18/0832249_F.sh tml [slashdot.org]

  • hmmm (Score:3, Funny)

    by the_other_one ( 178565 ) on Tuesday April 01, 2003 @12:01AM (#5635890) Homepage

    Perhaps this could slow down fiber optic communications enough for a server to survive the /. effect.

  • Where I am, it's definitely the 1st of April. You too, probably.

    So somehow, I don't quite believe this ...

  • Is it just me, (Score:4, Funny)

    by Mordant ( 138460 ) on Tuesday April 01, 2003 @12:35AM (#5636035)
    or does it seem like these folks are sort of headed in the wrong direction with this stuff?

    "Scotty, we need 38mph now, or we're all dead!"

    Just doesn't have the same ring to it, you know?
  • This light slowing device might find applications in the telecommunications industry.

    I thought the idea here was to go faster?

  • Arrgh! (Score:3, Funny)

    by TheSHAD0W ( 258774 ) on Tuesday April 01, 2003 @12:58AM (#5636199) Homepage
    We finally get the government to raise the speed limits on highways, so what do they do? Put a speed limit on light! Arrgh!

    You just can't win.
  • http://evil.minions.com/~bifrost/cnnsucks.jpg [minions.com]

    CNN reported that the space shuttle was traveling nearly 18 times the speed of light. We all laughed at this. Maybe this was true after all.

  • Wow! (Score:2)

    by dacarr ( 562277 )
    Wow! Now the telcos can slow us that much more!

  • Moo (Score:2)

    by Chacham ( 981 )
    Oh please. You call *this* a discovery? I can't take this lightly. The University of Freedonia they've proven that it can actually travel at -5 mph in a vaccuum, though it reality it'll be much slower.

  • Moo (Score:5, Funny)

    by Chacham ( 981 ) on Tuesday April 01, 2003 @01:58AM (#5636437) Homepage Journal
    The best part is, that we all know that when traveling faster than the speed of light in a vacuum, you can go backwards in time. So, by traveling slower than light in a vacuum, you move *forward* in time. As if this very moment I am traveling forward!

    If you'd like to try this, get an airtight container and step inside. Remove all the air (such as with a match). Then start moving slowly. When you get out of the jar you sill notice that it is *later* then when you got in!
    • That's the reason the article says it has applications in tellecomunications. Do you know any ad that'd be more appealing than:

      "John Doe was poor. Then he switch to AT&T and received 60 minutes entirely free to talk with himself, in the future, 30 years later. He read himself the Sports Almanac 2000-2020 and now he's a millionaire living in Beverly Hills. Do like him. Switch today. Know your future. Now with 60 free minutes to call yourself in the future. Offer does not apply in states where it doesn
    • Remove all the air (such as with a match)

      Translation: Take each carbohydrate in the match's cellulosic contents, combine with 6 oxygens from the air, and then release 6 carbon dioxides and 12 water molecules. Slap yourself on the forehead for having created more air.

    • Umm, oxidation is not the same as evacuation of air.
  • Time was increased by 34 minutes an hour to enable posting april 1 articles on march 31.
  • i knew my super time dilating sun-dial was late.

  • Non-believers (Score:5, Informative)

    by Sprunkys ( 237361 ) on Tuesday April 01, 2003 @02:43AM (#5636568)
    Not many people seem to believe this. I don't really see why not as this has already been done long ago [utwente.nl] by Ad Lagendijk [utwente.nl] and others (please note, the original research was done at Amsterdam, not the University of Twente).

    Furtermore, Bigelow e.a published their paper in the Physical Review Letters [aps.org] on March the 21st, not on the first of April. They submitted their paper on 31 October 2002.

    From what I could make up of it, Ad Lagendijk did this in the early nineties by having the light reflect off of particles and thus slowing it down effectively (it doesn't emerge on the other side of the container at t=x/c where t is the time, x is the width of the container and c is the speed of light).
    Bigelow, Lepeshkin and Boyd really just created a ruby crystal with an enormously high refractive index, effectively slowing down the light. Nothing really odd.

    Concerning the application of this research in telecommunications the article mentions the following:

    Boyd anticipates that the slow light device will find a role in the telecommunications industry. When two signals from fiber optic lines merge, the two signals may reach the merging router at the exact same moment and need to be separated slightly in time so they can be laid down one after another. Like two cars merging on a highway where one may need to slow down to let another car into the lane, a light-slowing device could help ease congestion on fiber optic lines and simplify the process of merging signals on busy networks.


    This I know nothing about, however, this does seem a bit odd to me as I don't know how they intend to figure out where the light is in order to know how much to slow it down.
    • Um you don't figure where the light is. you tweak the quality of the transmission. when you have very little interference, you've reached your target velocity. So it may actually require sending a test packet checking the results (all test packets are identical so we already know what the receiver should see). now if you can make this doubling of still faster than the state of the art congratulations.
      • Correct me if I'm wrong but:

        they want to put one transmission behind the other. So when the first transmission passes they have to move in the other one. Your method then only works if the transmissions from one source come in regular intervals and I'm not sure if this is the case. If not, then they have to know for every unique transmission when it has passed the point where they want to add the other transmission so they know when to let the other one on the main line.

        Right?

  • ...answer the age-old question:
    If you're driving the speed of light, what happens when you turn your headlights on?

    "Television? The word is half Greek, half Latin. No good can come of it.
    --- C. P. Scott

    • Simple: The light will appear to be traveling away from the car occupants at c, yet to a stationary observer the light will not appear to be traveling at 2c but only c. The car will also appear to be traveling at c, but of course the car will also appear to have zero length because of Lorentz-Fitzgerald contraction.

      The speed of light through a vacuum is always c.
  • Obviously that is too slow for light. April Fools!
  • Doesn't Einstein's theory of relativity go completly nuts if you change the speed of light?
    It doesn't make sense to me that if light goes slower then a mass will be worth less in terms of energy. Not that it made much sense with lightspeed as a constant factor but anyways I'm far from a scientist so I'm a little bit outside my teretory :)

  • One step closer to Mallet Temporal Ethernet Card (Score:3, Funny)

    by A55M0NKEY ( 554964 ) on Tuesday April 01, 2003 @12:26PM (#5638211) Homepage Journal
    Now that slow light is easy, we should be seeing the Mallet Temporal Ethernet Card in WAL*MART any day now!!

    It consists of a vacuum tube surrounded by two helical rubys wrapped around in opposite directions. The momentum of the slow light traveling through the rubies warps spacetime in this device between the anode and the cathode of the tube. The electron beam is aimed so as to take a path through the warped spacetime region that will lead from cathode to the anode at a previous time.

    Using this nifty device ( ONLY $19.95! on sale now at Best Buy! ) you can surf the web of the future easily! Just set the date you want to surf in your control panel and open a url.

    How does it work? Your computer will save the http request on disc and send it out on the date you set in the control panel. On that date, it will recieve a reply and send the result back to your present self by encoding it as a cathode ray signal and sending it through the temporally warped region of the vacuum tube. The signal will travel from the cathode in the future to the anode of now.

    Worried that your brand new outdated software will be incompatible with the future Internet? Will http be phased out? Not to worry!! You can download compatible software from the future using this device! To your computer the Mallet Temporal Network Card looks like any other ethernet card. It can even be used to surf the present by setting today's date in the control panel so you don't need to worry about finding slots for two network cards.

    That's right, for just $19.95 you can download movies that haven't even been made yet! You can read tomorrow's obituaries and avoid a nasty car accident, you can play the Lottery and win - EVERY TIME! You can play the stock market without risk of losing your hard earned cash. Read books and download software that hasn't been written yet, and OWN THE COPYRIGHT! The possibilities are endless.

    Mallet Temporal Network Card - How did you ever live without one?

  • This is how they'll throttle down my DSL, right? Damn that fast fibre! Gotta sell DSL in Lite Light, Extra Lite Light, Ultra Lite Light, and (eventually) stopped. No wait! They can do stopped now!
    --
    Malcolm

  • Primary use of this technology (Score:5, Funny)

    by Tikiman ( 468059 ) on Tuesday April 01, 2003 @01:07PM (#5638527)
    This technology will finally enable us to create "gun-style" laser weapons that can be ducked, dodged, and deflected with light sabres.
  • Hopefully this is explainable by someone with more physics knowledge than I have, but if you can make a laser move 127mph through a ruby, what happens if you shoot a matter-based beam, say, a beta (electron) ray through the same ruby that goes nearly the same speed or perhaps faster?

    Will we see relativistic effects, or is it unrelated to the medium, and only speed-in-vacuum is the limit?

    • Relativity only uses c, the speed of light in the vacuum. Hence this doesn't affect relativity.

      When particles go through a material faster than light goes through that material the result is Cerenkov Radiation, with quick google search gives a short and quick description here [umr.edu] and a longer in depth one here [mcmail.com]. Cerenkov radiation is basically like a sonic boom of light that produces the blue glow seen around nuclear reactors where the beta particles from the fisson are travelling faster than light through th

  • 127 mph: Still faster than a Honda Civic with "cool" ground-effects, huge spoiler, and coffee can muffler...well, you could slap an "R" sticker on it and you might get close.

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