May 21 2018
A new study has proposed that in contrast to earlier beliefs, a Multiverse - which includes many universes like our own - may not be so inhospitable to life. Queries related to the existence of other universes as part of a larger Multiverse, and whether they can nurture life, are hot topics in modern cosmology.
Artistic impression of a Multiverse—where our Universe is only one of many. According to the research varying amounts of dark energy have little effect on star formation. This raises the prospect of life in other universes—if the Multiverse exists. (Image credit: Jaime Salcido/simulations by the EAGLE Collaboration)
At present, a new study headed by Durham University in the United Kingdom and Australia’s University of Sydney, Western Sydney University, and the University of Western Australia has demonstrated that life can prospectively be common throughout the Multiverse if it prevails.
According to the researchers, central to this is dark energy, a strange “force” that has increased the speed of expansion of the Universe.
Multiverse Theory
Researchers state that prevalent theories for the origin of the Universe estimate that there is far more dark energy in our Universe than observed. The addition of huge amounts of this energy would lead to a rapid expansion, which might result in dilution of matter before the formation of any planets, stars, or life.
Introduced in the 1980s, the Multiverse theory can offer an explanation for the “luckily small” amount of dark energy in our Universe that allowed it to nurture life, of the various universes that failed.
In the new study, huge computer simulations of the cosmos were used to find out that the addition of dark energy, up to a few hundred times the amount detected in our Universe, would, in fact, have an unobtrusive effect on planet and stellar formation. According to the researchers, this leads to the possibility that life can exist throughout a broader range of other universes, if they occur.
The outcomes of the study will be published in the journal Monthly Notices of the Royal Astronomical Society in two associated papers. The simulations were generated through the Evolution and Assembly of GaLaxies and their Environments (EAGLE) project, one of the most realistic simulations of the observed Universe.
Star Formation
According to Jaime Salcido, a postgraduate student in Durham University’s Institute for Computational Cosmology, “For many physicists, the unexplained but seemingly special amount of dark energy in our Universe is a frustrating puzzle.”
“Our simulations show that even if there was much more dark energy or even very little in the Universe then it would only have a minimal effect on star and planet formation, raising the prospect that life could exist throughout the Multiverse.”
The Multiverse was previously thought to explain the observed value of dark energy as a lottery - we have a lucky ticket and live in the Universe that forms beautiful galaxies which permit life as we know it.
Our work shows that our ticket seems a little too lucky, so to speak. It’s more special than it needs to be for life. This is a problem for the Multiverse; a puzzle remains.
Dr Luke Barnes, a John Templeton Research Fellow at Western Sydney University
Dark Energy
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.
Dr Pascal Elahi, Research Fellow at the University of Western Australia
The researchers stated that their outcomes were unanticipated and could be tricky as they had doubts on the Multiverse theory’s potential to explain the observed value of dark energy. As specified by the study, people living in a Multiverse would expect to observe far more dark energy than they actually observe—possibly 50 times more than that observed in our Universe.
Despite the fact that the outcomes do not obviate the concept of the Multiverse, it appears that the minuscule amount of dark energy in our Universe would be better accounted for by a law of nature, thus far, undiscovered.
New Law of Physics
According to Professor Richard Bower from Durham University’s Institute for Computational Cosmology, “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.”
The study was carried out in collaboration with Liverpool John Moores University, United Kingdom; and Leiden University, The Netherlands.
The Science and Technology Facilities Council, United Kingdom; the European Research Council; The Netherlands Organisation for Scientific Research; the John Templeton Foundation; the International Centre for Radio Astronomy Research; and Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) funded the study.
Could a Multiverse be hospitable to life?
Simulations of the formation of a group of galaxies in an expanding universe, featuring no cosmological constant (left) and a very large cosmological constant (right). In the color scheme, lighter colors represent denser parts of the universe, when gravity is drawing matter together into galaxies. The simulation runs for 15 billion years. Without a cosmological constant (left), matter comes together under the attractive force of gravity into smaller galaxies, which combine into a large galaxy. With a large cosmological constant (right), the faster expansion of the universe stops matter from grouping together, and galaxies fail to form. (Video credit: Luke A. Barnes, Pascal J. Elahi, Jaime Salcido, Richard G. Bower, Geraint F. Lewis/EAGLE)