Physics

Simulations suggest multiverse is either teeming with life – or doesn't exist

Simulations suggest multiverse...
New simulations suggest life could be more common throughout the multiverse – or perhaps show that the multiverse doesn't exist after all
New simulations suggest life could be more common throughout the multiverse – or perhaps show that the multiverse doesn't exist after all
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Scientists have found that life is still possible even with far more dark matter than we have, and the results have some big implications for the multiverse theory
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Scientists have found that life is still possible even with far more dark matter than we have, and the results have some big implications for the multiverse theory
New simulations suggest life could be more common throughout the multiverse – or perhaps show that the multiverse doesn't exist after all
2/2
New simulations suggest life could be more common throughout the multiverse – or perhaps show that the multiverse doesn't exist after all

Our universe seems to contain a suspiciously perfect amount of dark energy to sustain life – any more and the fabric of reality would tear apart before life has a chance to take hold. But new research suggests that that might not be the case. By simulating how a universe would grow with different amounts of the stuff, scientists have found that life is still possible even with far more of it than we have, and the results have some big implications for the multiverse theory.

In the 1990s, it was found that the universe isn't expanding at a constant rate, it's accelerating, and this work earned its discoverers the 2011 Nobel Prize in Physics. Scientists dubbed the force behind this acceleration "dark energy," although that's more of a placeholder name than any actual description of it. To try to shed more light on dark energy, the Dark Energy Camera was launched in 2012 and a huge collection of data from the Survey was released earlier this year.

Dark energy has been calculated to account for more than 68 percent of the contents of the universe. But the question remains – why exactly that much? Our universe seems conveniently set up to support life, and it's assumed that if there was even a little bit more or less dark energy, then stars, planets and, by extension, life, wouldn't have been able to develop.

The multiverse theory helps explain this Goldilocks level of dark energy. According to this idea, our universe is just one of an infinite number of possible universes, so chances are that somewhere among them are universes where the conditions are just right. A selection bias known as the weak anthropic principle plays a part too – basically, the only way we're able to question how unlikely our existence is, is if we exist.

The new study, from researchers at the University of Sydney, Durham University, Western Sydney University and the University of Western Australia, looked at how different levels of dark energy might affect the development of life. The team produced simulations using the Evolution and Assembly of GaLaxies and their Environments (EAGLE) project, which is one of the most comprehensive simulations of the observed universe.

Scientists have found that life is still possible even with far more dark matter than we have, and the results have some big implications for the multiverse theory
Scientists have found that life is still possible even with far more dark matter than we have, and the results have some big implications for the multiverse theory

The study found that dark energy has a much smaller impact on the formation of stars and planets than was previously believed. Even when the simulated universe contained hundreds of times more dark energy than there is in our universe, or far less, life still found a way.

"We asked ourselves how much dark energy can there be before life is impossible?" says Pascal Elahi, an author of the study. "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."

That has wide-reaching implications for life in the multiverse. Previously, it was thought that most parallel universes would have evolved with conditions hostile to life, but the new study suggests life might be far more common across the multiverse. Or, perhaps this could be a blow to the very idea of a multiverse. After all, the amount of dark energy in our universe is no longer a suspiciously perfect amount. To the contrary, the researchers say the multiverse theory suggests there should be 50 times more dark energy in our universe than there is.

"The formation of stars in a universe is a battle between the attraction of gravity, and the repulsion of dark energy," says Richard Bower, an author of the study. "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."

Interestingly, Stephen Hawking's final paper, posthumously published earlier this month, also steps back somewhat from the multiverse theory, of which he was once a huge proponent.

The research was published in the journal Monthly Notices of the Royal Astronomical Society.

Source: Durham University (via EurekAlert)

9 comments
Tacky-on
Considering that the multiverse is not testable in any way known to man or science, wouldn't it better to call it "the multiverse hypothesis"? Calling it a theory puts far more credibility to it than it has earned. Or am I missing something?
Rustin Lee Haase
Show me the data and then we'll talk theory. Since you can't, by definition, show data fom another universe, one has no business talking about them scientifically. People may as well be talking about gnomes and unicorns. It all makes the same amount of sense. These humanists are going crazy trying to make order of the "universe" now that they have rejected it's Author and they are not doing very well.
AladdinConnolly
LOL @ Rustin. Tacky-on is correct that hypothesis is a more appropriate term, but your bizarre dig at humanist trying to make sense of the universe having rejected it's "author" is pure gobbledygook. It translates in English to "scientists are having a hard time fully comprehending the universe because it is vast and complex, and our current instruments cannot gather nearly enough data at this point, plus they were dumb enough to reject my ultimate explanation for everything. A simple word really, "magic".
relogic
@rustin The “Author” hypothesis had emerged since the first bi-per primate conjectured “What’s that mean, old volcano putting its hot, red sperm all over my mighty totem.” Those stubborn human (it’s) today and then should be dismissed to our own superstitious peril.
nekengren
Everything this article talks about are SIMULATIONS. Computer programs with finite data and assumptions. Let's start with whether dark energy actually exists. Let's start with the big bang and expanding universe theories. Trying to throw simulations of LIFE at these fantasies is beyond. Sorry but so many assumptions here that is becomes JUNK science.
MedfordChaz45
This will sound simplistic but when statistics such as the percentage 68% of the Universe is Dark Matter; what is being said is a percentage of the known Universe. Even Astronomers and Scientists don't know the size of the Universe and probably never will. So there is no size to calculate a percentage. For us simpletons, the Universe is Infinite, meaning formless and dimensionless. Usually, when referring to the Universe, scientists are talking about the contents of the Universe (like furniture in a room). So yes, we are hearing theoretical discussions. Our minds are not infinite but limited and can only think in terms of size, boundaries and size limits. But we keep on trying...
christopher
I'm perpetually amused that nobody has even bothered to work out the probability of life here at home, yet they go on to assume they can calculate it throughout the universe (and more) without having done the basic math first. Come on you lazy science geeks. Pull out some calculators, and start counting molecular collisions over time to figure this stuff out. It's not that hard, and the only person who even put passing thought into this so-far did so with pre-school forethought and such obviously incorrect scale that their answer is totally useless.
ProfessorWhat
... . . . uhhhh, this article is terribly, terribly wrong!! There needs to be an asterisked footnote at the end of the article acknowledging that neither dark energy or dark matter has ever been detected and discovered yet by anyone or by any experiment looking for either, whatsoever at all. And, NO: observations that we only think and guess are caused by dark energy or dark matter just doesn't prove their existence in any way, shape, or form, period. That's just not how science actually works!
Bob
Computer models can show whatever preconceived ideas you have. They don't PROVE anything.