They call it ‘Einstein’s dream come true.’ In 2004, astronomers from Australia, Italy, India, and the U.S. reported the discovery of the first known double pulsar system. PSR J0737-3039A and PSR JO737-3039B both have masses greater than that of our sun, but are only 20 kilometers across. With an orbital separation less than the sun’s diameter, they orbit each other in only 2.4 days.
Astronomers have confirmed Einstein’s theory of gravity using a pair of pulsars two thousand light-years away.
Maura McLaughlin: It turns out that systems like this are kind of like Einstein’s dream come true, because we have these two extremely massive objects in orbit around each other, and we can measure all of these really cool relativistic effects that we can’t measure on Earth.
That’s astronomer Maura McLaughlin of West Virginia University. She helped discover the pulsar pair. A pulsar is a burned-out star. It’s as massive as our sun, but packed into the size of a city. McLaughlin told EarthSky that, as pulsars spin hundreds of times each second, they emit pulses of radio waves like the beacon of a lighthouse.
Maura McLaughlin: So we can predict with really incredible accuracy exactly what time we expect the next pulse from the pulsar to arrive. And we can see tiny little perturbations on the arrival times of the pulses due to effects predicted by Einstein, such as the warping of space-time. We can actually see that space-time is curved in the presence of these really massive objects.
McLaughlin said data from the double pulsar helped confirm Einstein’s general relativity theory to an accuracy of a fraction of a percent.
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Our thanks to:
University of West Virginia
In his years with EarthSky, Jorge Salazar conducted thousands of in-depth interviews with scientists. He knows a lot about as diverse as nanotechnology, ecosystem-based management, climate change, global health, international environmental treaties, astrophysics and cosmology, and environmental security. Jorge currently works as a Technical Writer/Editor for the Texas Advanced Computing Center, which designs and deploys powerful advanced computing technologies and innovative software solutions for scientific researchers.