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186,000 Miles Per Second. It's Not Just a Good Idea, It's the Law.
So, has the speed of light, one of the bedrock constants in physics, changed over the life of the universe? Maybe, maybe not, but they sure are looking hard to check:
A new study of distant galaxies is adding a fresh perspective to the debate over whether a fundamental physical constant has actually changed over time. The work suggests the number has not varied in the last 7 billion years, but more observations are still needed to settle the issue.
Essentially, one study found it had changed, but subsequent studies have not. This is a new technique to look at the problem, but they're just starting out and their "resolution" isn't as good as the previous experiments, at least for now.
No, I don't know what good it does us to know this either. But then again, that's what people said about guys screwing around with static electricity back in the 18th century, and look where that's go us.
Well, if other teams are not able to duplicate the results then you have to be cautious.
I wish they gave more information regarding the new observation methods. Guess I will have to find the time to search it out.
Posted by: Joshua on April 20, 2005 09:32 AMWell it's very important to double check ourself. I mean we can bring light to a standstill in the lab and then speed it back up past light speed. I mean if we can make light go faster than the speed of light and slower than the speed of light what's the say that there aren't natural phenomenon out there doing the same thing. It would definitely mess with our math on certain things if the speed we knew was only true on Earth.
Posted by: ManDrake on April 21, 2005 07:41 AMWell, the light experiments are interesting, but it's hard to prove that they actually did make light faster than light. From what I heard, the substance they put light through was actually a light-storage medium that had been already stocked to full capacity; the pulse of light that emerged from the other side was actually stored light released when the new light was introduced, not the original pulse travelling faster than light.
Suppose you had a 500,000 mile long tube, wrapped around the earth so that both ends are within visible distance of each other, just large enough in diameter to hold a single line of ping-pong balls, and that it was already completely filled with just such a line of ping-pong balls (and lubricant that kept the combined friction of a billion or so ping-pong balls from preventing the balls from moving freely). Then you push a ping-pong ball into one end. Instantly, a ping-pong ball pops out the other end. Look, you made a ping-pong ball travel faster than the speed of light! Well, except you didn't.
But how can a photon have mass. Einstien's theory tells us that mass cannot travel at the speed of light because the energy required to accelerate it would be converted into mass, thus increasing the amount of energy required and causing a feed-back loop.
If a photon has mass it cannot travel at the speed of light, which means light does not travel at light speed unless it is not composed of photons at all.
Posted by: Nishant on September 8, 2006 02:03 PMHow can a photon have mass. Einstien's theory tells us that mass cannot travel at the speed of light because the energy required to accelerate it would be converted into mass, thus increasing the amount of energy required and causing a feed-back loop.
If a photon has mass it cannot travel at the speed of light, which means light does not travel at light speed unless it is not composed of photons at all.
Posted by: Nishant on September 8, 2006 02:03 PMAs I understand it, photons do not in fact have mass. When I googled I found:
"No, photons do not have mass, but they do have momentum. The proper, general equation to use is E2 = m2c4 + p2c2 So in the case of a photon, m=0 so E = pc or p = E/c. On the other hand, for a particle with mass m at rest (i.e., p = 0), you get back the famous E = mc2.
This equation often enters theoretical work in X-ray and Gamma-ray astrophysics, for example in Compton scattering where photons are treated as particles colliding with electrons. "
Posted by: Scott on September 8, 2006 02:25 PM