Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Intergalactic Race Shows that Einstein Still Rules

pickens (49171) writes | more than 4 years ago

Space 0

Ponca City, We love you writes "The NY Times reports that after a journey of 7.3 billion light-years, a race between gamma rays ranging from 31 billion electron volts to 10,000 electron volts, a factor of more than a million, in a burst from an exploding star have arrived within nine-tenths of a second of each other in a detector on NASA’s Fermi Gamma-Ray Space Telescope confirming Einstein’s proclamation in his 1905 theory of relativity that the speed of light is constant and independent of its color, energy, direction or how you yourself are moving. Some theorists had suggested that space on very small scales has a granular structure that would speed some light waves faster than others — in short, that relativity could break down on the smallest scales. Until now such quantum gravity theories have been untestable because ordinarily you would have to see details as small as the so-called Planck length, which is vastly smaller than an atom — to test these theories in order to discern the bumpiness of space. The spread in travel time of 0.9 second, if attributed to quantum effects rather than the dynamics of the explosion itself, suggested that any quantum effects in which the slowing of light is proportional to its energy do not show up until you get down to sizes about eight-tenths of the Planck length. "This measurement eliminates any approach to a new theory of gravity that predicts a strong energy dependent change in the speed of light," says Peter Michelson of Stanford. “"To one part in 100 million billion, these two photons traveled at the same speed. Einstein still rules.""

Sorry! There are no comments related to the filter you selected.

Check for New Comments
Slashdot Login

Need an Account?

Forgot your password?