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Sunday, January 17, 2010

Pulsar Radio Signals Faster-than-Light

Astrophysicists at the University of Texas at Brownsville have been studying Pulsar PSR B1937+21 about 10,000 light years away to determine why the radio waves emitted from the pulsar seem to have been traveling faster than the speed of light, according to a new study set to be published in the Astrophysical Journal and reported upon in PhysicsWorld.com.

Pulsar PSR B1937+21 is the second fastest spinning pulsar yet cataloged, and spins about 642 times around every second. The radio pulse from the pulsar is suspected to have picked up some of the excess speed by passing through a cloud of neutral hydrogen atoms, which causes the radio waves to increase their electromagnetic wavelength (a process called "anomalous dispersion"), reports Physics.org. [Hat tip to Jacob Atkins.]

2 comments:

Anonymous said...

Important note - The emitted pulses do not exceed the speed of light, but the group velocities of resonant waves within the pulses can.

Explanation -

Imagine a train traveling at the speed of light (like a pulsar pulse). A man near the rear of the train walks to the front of the train. From the man's perspective, he only moved at walking speed (his group velocity). From the outside perspective, his velocity is the speed of the train (light-speed) plus his walking speed (group velocity). Although this combined speed is superluminal, when he reaches the front of the train, he must stop. He is stuck on the train, which will always arrive at the station on-time, according to standard light speed. Sadly, no speed limits are broken.

Anonymous said...

Your explanation makes no sense.
Train speed=speed of light
Persom speed=speed of light+speed of walking

With every step person makes, he travels more distance then train during the same time, thus person have greater speed