Astronomers have discovered a celestial counterpart to the philosophical question "Does a tree make a sound if it falls in a forest with no one around to hear it?"

It Came From Here

In this case, scientists have found a definite sound, though it was detected just once and only for a fraction of a second, but nothing to explain its origin.

The signal, which was buried in archived studies of a pair of small nearby galaxies called the Magellanic Clouds, was extremely strong and so oddly skewed that scientists believe it emanated from a cosmic event that took place about three billion light-years from Earth.

The Magellanic Clouds, a pair of small galaxies that orbit our own Milky Way, are only about 200,000 light-years away.

"It was a bit of luck that the survey included some observations of the sky surrounding the Clouds," said David Narkevic, an undergraduate student at West Virginia University, who was reviewing the observations of the Small Magellanic Cloud made by the Parkes radio telescope in Australia.
Narkevic and a research team led by West Virginia physics professor Duncan Lorimer were looking for undiscovered pulsars, which are believed to be a type of neutron star that rotates very quickly and emits a strong and regular radio signal.

In combing through 480 hours of recorded data, the researchers instead happened upon a solitary, strong radio burst which lasted about five milliseconds. The signal was spread out, with the higher frequencies arriving at the telescope before the lower frequencies, which happens when a signal passes through electrically charged gas in interstellar and intergalactic space.

The discovery has left scientists baffled as to what caused the signal, but there are plenty of guesses. One idea that has captured the team’s fancy is that a pair of extremely dense neutron stars collided and merged, releasing a huge amount of energy ranging from gamma rays to the radio burst.

Another theory is that the signal was the dying gasp of an evaporated black hole. British physicist Stephen Hawking has described a process that would drain black holes of their mass and energy. Black holes are objects so dense that not even light can escape their gravitational grasp.

"This burst represents an entirely new astronomical phenomenon," said Matthew Bailes of Swinburne University in Australia.

Scientists, who reported the finding in this week’s issue of Science, are plowing through other archived pulsar surveys in hopes of finding more stray radio bursts.

Via: Discovery