Melbourne: The universe is slowly dying but we have another 100 billion years, according to a new study of 200,000 galaxies, which found that the energy generated by the galaxies is half of what it was two billion years ago.
Researchers from the International Centre for Radio Astronomy Research (ICRAR) in Western Australia used seven of the world's most powerful telescopes to observe galaxies at 21 different wavelengths from the far ultraviolet to the far infrared.
Initial observations were conducted using the Anglo-Australian Telescope in New South Wales and supporting observations were made by two orbiting space telescopes operated by NASA and another belonging to the European Space Agency.
The research is part of the Galaxy and Mass Assembly (GAMA) project, the largest multi-wavelength survey ever put together.
"We used as many space and ground-based telescopes we could get our hands on, to measure the energy output of over 200,000 galaxies across as broad a wavelength range as possible," said ICRAR Professor Simon Driver.
The survey data, released to astronomers around the world, includes 200,000 galaxies each measured at 21 wavelengths from the ultraviolet to the far infrared and will help scientists better understand how different types of galaxies form.
"It's going to be a long retirement and a slow dwindling process. It's about 100 billion years or so until all starlight stops being produced," Driver told reporters.
Driver, who heads up the GAMA team, says the study set out to map and model all of the energy generated within a set volume of space.
All energy in the universe was created in the Big Bang with some portion locked up as mass. Stars shine by converting this mass into energy as described by Einstein's famous equation E=MC2.
"While most of the energy sloshing around was created in the aftermath of the Big Bang, additional energy is constantly being released by stars as they fuse elements like hydrogen and helium together," Driver said.
"This newly released energy is either absorbed by dust as it travels through the host galaxy, or escapes into intergalactic space and travels until it hits something such as another star, planet, or very occasionally a telescope mirror," he said.
The fact that the universe is slowly fading has been known since the late 1990s but this work shows that it's happening across all wavelengths from the ultraviolet to the
infrared, representing the most comprehensive assessment of the energy output of the nearby universe.
"The universe is fated to decline from here on in, like an old age that lasts forever. The universe has basically plonked itself down on the sofa, pulled up a blanket and is about to nod off for an eternal doze," Driver added.
