Could a Multiverse be hospitable to life?

Multiverse, where our Universe is only one of many might not be as inhospitable to life as previously thought. A new study led by researchers at Durham University, UK, indicates that life could potentially be common throughout the Multiverse, if it exists.

Questions about whether other universes might exist as part of a larger Multiverse, and if they could harbour life, are burning issues in modern cosmology. The key to this puzzle is dark energy, a mysterious force that is accelerating the expansion of the Universe.

Scientists say that current theories of the origin of the Universe predict much more dark energy in our Universe than is observed. Adding larger amounts would cause such a rapid expansion that it would dilute matter before any stars, planets or life could form.

The Multiverse theory, introduced in the 1980s, can explain the 'luckily small' amount of dark energy in our Universe that enabled it to host life, among many universes that could not.

Using simulations of the cosmos, under the EAGLE [Evolution and Assembly of GaLaxies and their Environments] project, researchers have found that adding dark energy, up to a few hundred times the amount observed in our Universe, would actually have a modest impact upon star and planet formation.

This opens up the prospect that life could be possible throughout a wider range of other universes, if they exist.

"We asked ourselves how much dark energy can there be before life is impossible? Our simulations showed that the accelerated expansion driven by dark energy has hardly any impact on the birth of stars, and hence places for life to arise. Even increasing dark energy many hundreds of times might not be enough to make a dead universe," said Dr Pascal Elahi, one of the researcher of the study.

Researchers said their results were unexpected and could be problematic as they cast doubt on the ability of the theory of a Multiverse to explain the observed value of dark energy. According to the research, if we live in a Multiverse, we'd expect to observe much more dark energy than we do - perhaps 50 times more than we see in our Universe.

Although the results do not rule out the Multiverse, it seems that the tiny amount of dark energy in our Universe would be better explained by an, as yet, undiscovered law of nature.

Professor Richard Bower, in Durham University's Institute for Computational Cosmology said, "The formation of stars in a universe is a battle between the attraction of gravity, and the repulsion of dark energy. We have found in our simulations that universes with much more dark energy than ours can happily form stars. So why such a paltry amount of dark energy in our Universe?"

"I think we should be looking for a new law of physics to explain this strange property of our Universe, and the Multiverse theory does little to rescue physicists' discomfort," he added.

Image Credit: Jaime Salcido/simulations by the EAGLE Collaboration Original 
Source: Durham University