Apologies to Superman

I always thought it was baloney that he could fly around the earth backwards faster than the speed of light to rescue Lois Lane.

Check this out.

As I understand it, CERN's FTLS neutrinos may actually be measuring errors. However, proving or disproving their existence is very difficult since there are only two other places in the world with particle accelerators powerful enough to reproduce the results, one in Japan, recovering from the recent earthquake/tsunami, and the other at FermiLab in Chicago. Unfortunately, the equipment at FermiLab needs an upgrade as it is currently not sensitive enough to overcome the margin of error.

I think Superman would accept your apology.

CERN's Collider... That's a lot of gigawatts...

Please note that I do not claim that the following comments are fact or even true. They are my vague recollections from reading a physics book 40+ years ago while taking a class in which I didn't really have a lot of interest; i.e., my memories on this are subject to significant potential errors.

With that disclaimer, I recall reading about something that had been measured as traveling at a greater speed than light (electromagnetic radiation) can travel in a vacuum: electromagnetic radiation passing through an ionized atmosphere. As I remember reading it, the ionized atmosphere provided a kind of superconducting medium -- not, I think, like the low-temperature, zero-electrical-resistance superconductors -- but superconducting as in increasing the speed of the waves/particles rather than retarding them as do other media. Does anyone who paid more attention in such physics courses remember something like that? I was much more into the classical mechanics aspects of physics rather than that relativity stuff, so I may have screwed this particular topic up when reading it. Or just misremembered it over the decades.

Mike, does this thread warrant review/comment by your dad?

As far as I know some models posed tachyons can only travel faster than light.

And as I recall, Einstein's theories forbid any object with mass from traveling at the speed of light in a vaccum, not faster or slower; nor does the restriction apply to massless aprticles like photons.

Quote: Doc

Does anyone who paid more attention in such physics courses remember something like that?

I am guessing, you are thinking about either the Cherenkov effect or phase velocity.
The former is an analogue of a sonic boom for superluminal particles. It happens when the speed of a particle exceeds the speed of light in the particular medium, not in vacuum. This is a well known effect, it is not uncommon for high-energy particles to exceed the speed of light. However, note that the speed of light in vacuum is not exceeded, there is nothing special about the speed of light in a particular medium.

The other possibility, that you might be thinking about is group velocity. Apparently it is possible to create a medium with an exotic property (anomalous dispersion), and send laser pulses through it in such a way, that the group velocity of those pulses will exceed the speed of light in vacuum. I doubt this was known 40 years ago though. Now, phase velocity of any non-zero mass wave-particle is greater than the speed of light (this is well known since early days of quantum mechanics).
Neither of these contradicts relativity (or rather the causality, since relativity itself actually does not forbid superluminal transmission), because neither mass nor information is transferred with these speeds, and the signal speed still stays below "c".

If CERN neutrinos are really confirmed to have traveled faster than light, it would definitely be the first such observation since the beginning of time.

Quote: odiousgambit

I always thought it was baloney that he could fly around the earth backwards faster than the speed of light to rescue Lois Lane.

So Bizarro World does exist. I knew it.

I wonder if they forgot to take into account the rotation of the earth.

Quote: Keyser

I wonder if they forgot to take into account the rotation of the earth.

Write them a letter ;)

Quote: Keyser

I wonder if they forgot to take into account the rotation of the earth.

Probably a Coriolis effect.

And weaselman, thanks for your comments. It's not so much that I forgot part of my physics training but more that there was a bunch of areas that didn't interest me enough to learn properly in the first place. And a lot of "modern physics" stuff that wasn't even known when I was in school.