A pair of stars orbiting each other nearly 7,000
light years from Earth have provided more evidence that Albert Einstein's
theory of general relatively is correct.
Astronomers measured bursts of energy from a neutron
star which is being orbited by a smaller white dwarf star.
The gravity created by the neutron star, which is a
super dense spinning pulsar, created a wrinkle in the fabric of space time in a
way predicted by Einstein in his famous theory in 1915.
This image shows the Hubble Space Telescope's view of Supernova UDS10Wil more than 10 billion years ago. |
The neutron star, which is just 12 miles across but
weights twice as much as our own sun, has gravity that is 300 billion times
stronger than that felt on the surface of Earth.
At the centre of this star, a billion tonnes of
matter would be squeezed into an areas the size of a sugar cube.
This enormous gravitational force should create a
distortion in space-time according to Einstein's theory.
As the white dwarf – a glowing remnant of another
dead star – orbits the neutron star they should create wrinkles that move out
in space time known as gravitational waves.
Over time this causes the two stars to move closer
together as these wrinkles send energy out into space.
Astronomers on Earth were able to use a global network
of telescopes to measure this by timing radio bursts emitted from the neutron
star, also known as a pulsar, over time.
"We thought this system might be extreme enough
to show a breakdown in General Relativity, but instead, Einstein's predictions
held up quite well," said Dr Paulo Freire, from the Max Planck Institute
for Radioastronomy in Germany.
Einstein’s general theory of relativity, which
explains gravity as a consequence of the curvature of space-time created by the
presence of mass and energy, has withstood all tests since it was first
published almost a century ago.
Physicists, however, believe it cannot explain all
of the effects seen in the universe as it is not compatible with quantum
theory, which is used to explain the forces that hold atoms and subatomic
particles together.
Instead they have come up with other theories of
gravity that they believe can be spotted in extremely strong gravitational
fields that are too large to be found in our own solar system – much like the
one they were observing.
Although the findings, which are published in the
journal Science, failed to reveal any breakdown in Einstein's theory, they have
raised hopes that researchers might be able to directly detect gravitational
waves.
“Our radio observations were so precise that we have
already been able to measure a change in the orbital period of 8 millionths of
a second per year, exactly what Einstein’s theory predicts,” states Paulo
Freire, another member of the international team that carried out the study.
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