Over 100 scientists have been working on the Galaxy and Mass Assembly survey (GAMA), using some of the world's most powerful telescopes to study the amount of energy given off by 200,000 galaxies.
Their latest findings indicate that the cosmos is radiating only half as much energy as it was 2 billion years ago.
"While most of the energy sloshing around in the Universe arose in the aftermath of the Big Bang, additional energy is constantly being generated by stars as they fuse elements like hydrogen and helium together," explained Simon Driver of the University of Western Australia, who heads up the GAMA.
"This new 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, a planet, or, very occasionally, a telescope mirror."
Scientists first posited the notion of a universal "slow down" in the late 1990s, with new technology allowing astronomers to measure a greater band of wavelengths to test out the theory.
Energy that's been bouncing about since the Big Bang isn't disappearing - it's just that, after 13.8 billion years, it's slowing down, spreading out and dissipating into more and more space. Or, as Driver puts it, "The universe has basically sat down on the sofa, pulled up a blanket and is about to nod off for an eternal doze."
The good news is, we're not about to witness it slip into nothingness any time soon - with conservative estimates pointing to a few trillion years. "It will just grow old forever, slowly converting less and less mass into energy as billions of years pass by until eventually, it will become a cold, dark and desolate place, where all of the lights go out," said contributing astronomer Luke Davies.
To soak yourself in more glorious GAMA observations, check out the following informative video form the International Centre for Radio Astronomy Research. It'll come handy for a pub chat in the near future.