New research has explained the reason behind how supermassive black holes get to be as large as they are, the scientific team reported in a press release.

Study co-author Dr. Ramesh Bhat, of the Curtin University department of the International Centre for Radio Astronomy Research (ICRAR), said gravitational waves have allowed the team to observe the black holes.

"This is the first time we've been able to use information about gravitational waves to study another aspect of the Universe - the growth of massive black holes," he said. "Black holes are almost impossible to observe directly, but armed with this powerful new tool we're in for some exciting times in astronomy. One model for how black holes grow has already been discounted, and now we're going to start looking at the others."

Gravitational waves are ripples in space-time caused by massive spatial objects changing in direction or speed. Albert Einstein predicted these massive bodies orbit each other, creating the waves. When galaxies merge, their central black holes are bound to meet.

"When the black holes get close to meeting they emit gravitational waves at just the frequency that we should be able to detect," Dr. Bhat said.

Astronomers have been long searching for these waves using the Parkes radio telescope as well as 20 small rotating stars called pulsars. Pulsars act as precise timing mechanisms for astronomers to tell distance and time. Their pulses' arrival at Earth can be measured with the utmost precision.

The research team's findings were published Thursday in the journal Science.

"The strength of the gravitational wave background depends on how often supermassive black holes spiral together and merge, how massive they are, and how far away they are. So if the background is low, that puts a limit on one or more of those factors," said Dr. Bhat. "The [Murchison Widefield Array] large view of the sky can be exploited to observe many pulsars at once, adding valuable data to the [Parkes Pulsar Timing Array] project as well as collecting interesting information on pulsars and their properties."