Double pulsar puts Einstein to the test

Jun 01, 2005
Double pulsar puts Einstein to the test

Einstein has kept his crown. His general theory of relativity, published in 1916, has stood up to the toughest tests astronomers have so far devised - tests based on a unique pair of pulsars found with CSIROs Parkes telescope in 2003.

Image: An artist's impression of the double-pulsar system; Image by John Rowe Animations

Dr Ingrid Stairs, an assistant professor at the University of British Columbia in Vancouver, Canada, reported the work by an international team to the American Astronomical Society's meeting in Minneapolis on Monday (30 May).

"This pair of orbiting pulsars, discovered only two years ago, is one of the best laboratories in the Universe for studying the effects of Einstein's general theory of relativity," Dr Stairs said.

Astronomers have been closely tracking this exciting duo with CSIRO's 64m Parkes telescope in central New South Wales, Australia; the US National Science Foundation's 100m Robert C. Byrd Green Bank Telescope in West Virginia, USA and the 76m Lovell telescope at Jodrell Bank Observatory in England.

Because the pulsars orbit each other so quickly - once every 2.4 hours - several general relativity effects are predicted to be large. Four effects were measured within a few months of the pulsars' discovery.

Now the astronomers have measured another significant phenomenon: the stars' orbit is shrinking because the pulsar system is losing energy by emitting gravity waves. At present the shrinkage is tiny - just 7mm a day - but the loss will accelerate in future. And that means the pulsars will collide in 85 million years, the scientists say.

The decay of the orbit is exactly what general relativity predicts.

Other general relativity effects are starting to crop up. One is geodetic precession, the stars wobbling like spinning tops as they move in the curved space-time of their orbit. If this is happening it should result in changes in the observed shapes of the radio pulses, as telescopes on Earth start to see slightly different parts of the irregularly shaped radio beams.

The team already has good evidence for this wobble in the more slowly spinning pulsar. Sensitive observations are now revealing small changes in the beam shape of the other, faster-spinning pulsar.

"More observations will help us work out the full geometry of the system, and test general relativity in even more ways," says team member Dr Dick Manchester of CSIRO.

Links: Details of the pulsar system, called J0737-3039, can be found at www.atnf.csiro.au/news/press/double_pulsar/

Source: CSIRO

Explore further: NASA spacecraft nears historic dwarf planet arrival

add to favorites email to friend print save as pdf

Related Stories

The mystery of pulsar rarity at the center of our galaxy

Nov 06, 2014

The galactic center is a happening place, with lots of gas, dust, stars, and surprising binary stars orbiting a supermassive black hole about three million times the size of our sun. With so many stars, as ...

Catching a gravitational wave

Jun 26, 2014

(Phys.org) —When Albert Einstein proposed the existence of gravitational waves as part of his theory of relativity, he set in train a pursuit for knowledge that continues nearly a century later.

Recommended for you

NASA spacecraft nears historic dwarf planet arrival

1 hour ago

NASA's Dawn spacecraft has returned new images captured on approach to its historic orbit insertion at the dwarf planet Ceres. Dawn will be the first mission to successfully visit a dwarf planet when it enters ...

An old-looking galaxy in a young universe

4 hours ago

A team of astronomers, led by Darach Watson, from the University of Copenhagen used the Very Large Telescope's X-shooter instrument along with the Atacama Large Millimeter/submillimeter Array (ALMA) to observe ...

Giant methane storms on Uranus

6 hours ago

Most of the times we have looked at Uranus, it has seemed to be a relatively calm place. Well, yes its atmosphere is the coldest place in the solar system. But, when we picture the seventh planet in our ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.