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Tuesday, September 2, 2014

More Evidence Against Faster-Than-Light Neutrinos

Posted by jlwile on June 7, 2012

In September, a high-energy physics group released some results indicating that they saw neutrinos moving faster than the speed of light. This is a violation of Einstein’s special relativity, so it was met with much skepticism. Earlier this year, the group announced that it had found a problem with its experimental setup, and it wasn’t clear whether or not their result was valid. Well, another group has performed a similar experiment at the same laboratory, and they found that the neutrinos were not moving faster than light. I think it’s now safe to say that the faster-than-light neutrino result was incorrect.

Comments

4 Responses to “More Evidence Against Faster-Than-Light Neutrinos”
  1. This is a disappointment for those of us who would like to have a warp drive, but it is really what was to be expected.

  2. jlwile says:

    Yes, Mike, reality has a way of stomping on our dreams, doesn’t it?

  3. Lionhearte says:

    I’m curious about something. The speed of light, as we were always told, is a constant and nothing can travel faster than it. I’m supposing the real “issue” here is if the neutrinos could travel FASTER than 186,282 mp/s? Because although Einstein has not been proven wrong about anything traveling faster than the SoL, he never said anything about the SoL going slower.

    Which is what happened multiple times in the past few decades. I believe in 1999 a professor at Harvard and her colleagues brought light down to 38 mp/h, and in 2001 (?) Light was brought to a full stop and released.

    In the latter case, a snail could travel faster than light. So, like I said, the real “issue” would be if anything could travel faster than 186,282 mp/s, or am I incorrect?

  4. jlwile says:

    Lionhearte, Einstein didn’t say that nothing could travel faster than the speed of light. He said that nothing with mass can accelerate through the speed of light in a vacuum (186,282 miles/sec). These are not minor distinctions. First, light travels at different speeds depending on the medium through which it is traveling. For example, when light travels through pure water at 20 degrees C, its speed is 1.333 times slower than when it is traveling through empty space. When scientists slowed light down, they simply devised a medium through which it traveled extraordinarily slowly. The light that was slowed to a “stop” really wasn’t stopped. It was passed around between the atoms of the medium until they were excited by a specific wavelength of light, and then they released it.

    Second, things can, theoretically, travel faster than light without violating relativity. For example, if you stood on the earth and shined a bright laser onto a white surface on the moon and then moved the laser through an angle of several degrees very quickly, the laser dot on the white surface would move faster than 186,282 miles/sec. This would not violate relativity, because the laser dot cannot be used to transmit information faster than light, and that’s the real issue. If you could transfer information faster than light, then there would be certain reference frames in which effect would precede cause, and that’s what Einstein couldn’t allow. In addition, there are theoretical particles called “tachyons” that have mass but travel faster than light. We have no idea whether or not they exist, but they can exist without violating relativity, because once again, they cannot be used to transmit information. Also, they are formed already traveling faster than light. Thus, they do not have to accelerate through it.

    Now…with all that said, your main point is right. It’s not the speed of light in any medium that matters. It is only the speed of light in a vacuum. So…the proper statement would be: “Nothing with mass can accelerate through 186,282 miles/sec, and nothing that can transmit information can travel faster than 186,282 miles/sec.”

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