Researchers use satellite launch blunder to test relativity
Pop quiz, hotshot. You've just launched a pair of GPS satellites into the wrong orbit, rendering them useless for navigation. What do you do? If you're the European Space Agency (ESA), you re-purpose them to precisely test Albert Einstein's theory that clocks slow down near heavy objects. Since the Galileo satellites were placed in elliptical, rather than circular orbits by Russian Soyuz rockets, they pass closer to Earth at certain points. Our planet bends the fabric of space-time, so the super-precise atomic clocks on-board the satnavs will theoretically slow during those times, then speed up again when the craft move away.
Ground stations will track their precise height above the earth using lasers (to within a few centimeters), allowing researchers to test Einstein's time dilation principle, part of the theory of relativity. Similar experiments like Gravity Probe B have already confirmed it to a certain degree, but since the Galileo craft are in stable (but wrong) orbits, the ESA team will be able to run the tests for a much longer period than ever before.
"The satellites have accidentally become extremely useful scientifically. Now, for the first time since Gravity Probe A, we have the opportunity to improve the precision and confirm Einstein's theory to a higher degree," said ESA satnav specialist Javier Ventura-Traveset. Meanwhile, the agency is still trying to maneuver the craft into the correct orbits, so they might eventually become useful for GPS navigation again, too.
