Could extraterrestrial life exist in a parallel universe? Computer simulations from two new studies suggest that the idea was out of this world.
Should the search for extraterrestrial life in our universe go blank, it might be worthwhile to check in with a neighbor
According to a new pair of studies in the Monthly Notices journal of the Royal Astronomical Society, there is one good chance that life-giving planets could exist in a parallel universe ̵
The idea that our universe is only one of many, perhaps infinite, other universes is called multiverse theory. Scientists used to think that such parallel universes, if they exist, would have to meet extremely stringent criteria to enable the formation of stars, galaxies, and life-supporting planets as they occur in our own universe. [5 Reasons We May Live in a Multiverse]
In the new study, researchers conducted a massive computer simulation to build new universes under different starting conditions. They found that the conditions for life could be a little wider than previously thought, especially when it comes to the mysterious pull of dark energy.
Dark energy is a mysterious, invisible force that one suspects in nothing spaces of our universe. You could think about it as the Archnemesis of Gravity; As gravity pulls matter closer, the dark energy hurls it apart – and dark energy wins this cosmic tug-of-war in a practical way.
Not only is our universe expanding, thanks to the constant, invisible burst of dark energy, but also the rate of this expansion is getting faster and faster every day. It is believed that as more empty space appears in the universe, even more dark energy fills it. (Dark energy is not the same as dark matter, which is an abundant, invisible form of matter responsible for some very strange gravitational phenomena in space.)
Scientists do not know exactly what dark energy is or how it works ; some think that it is an intrinsic property of space – what Einstein called the cosmological constant – while others attribute it to a fundamental force called quintessence, with its own dynamic rules. Others do not even agree that it exists. But whatever it is, anyone can agree that there is a whole lot: According to the best current estimates, nearly 70 percent of the mass energy of our universe can be dark energy.
This set, for whatever reason, is in the right area for galaxies to grow and promote life. It is believed that if we lived in a universe with too much dark energy, space could expand faster than galaxies could possibly form. Too little dark energy and bursting gravity could cause each galaxy to collapse before life even had a chance.
But the question of how much dark energy is "too much" or "too little" is a topic for debate – and this question of quantity was what the authors of the new studies wanted to narrow down.
Life finds a way
In several experiments, an international research team from England, Australia and the Netherlands used a program called Evolution and Assembly of Galaxies and Environments to promote the birth, life and eventual death of various hypothetical universes simulate. In each simulation, the researchers adjusted the amount of Dark Energy present in this universe, ranging from zero to several hundred times as much as in our own universe.
The good news: Even in universes with 300 times as much dark energy as we did Life found a way.
"Our simulations showed that the accelerated expansion driven by dark energy has little effect on the birth of stars and therefore on life experiences," says co-author Pascal Elahi, a researcher at the University of Western Australia, said in a statement. "Even the increasing dark energy that exists hundreds of times may not be enough to create a dead universe."
This is good news for fans of extraterrestrial life and the multiverse theory. But one bigger question remains: If galaxies could develop so much dark energy, why did our universe get such a seemingly small amount?
"I think we should look for a new law of physics to explain this strange property of our universe," said co-author Richard Bower, a professor at the Institute for Computational Cosmology at Durham University.
Of course it is easier said than done to find new laws of physics. Scientists are not going to give up, but maybe, to hedge their bets, they should look for a parallel universe where an intelligent life has already done it for them.
Originally published on Live Science.