A novel theoretical model based on universal expansion and star formation suggests that our universe might not have the optimal conditions for life.
Despite the less favorable dark energy density observed, life is still possible, challenging previous cosmological models and changing our perspective on our existential significance.
A new theoretical model estimates the likelihood of intelligent life developing in our Universe—and in any hypothetical universes beyond it—echoing aspects of the well-known Drake Equation.
The Drake Equation, developed by American astronomer Dr. Frank Drake in the 1960s, aimed to calculate the number of detectable extraterrestrial civilizations in our Milky Way galaxy.
Now, over 60 years later, a team of astrophysicists led by Durham University has introduced a different model. Rather than focusing on extraterrestrial civilizations, this model examines the conditions created by the accelerated expansion of the Universe and the rate of star formation.
This expansion is believed to be driven by dark energy, a mysterious force that comprises over two-thirds of the Universe.
Probabilities in the Multiverse
Since stars are a precondition for the emergence of life as we know it, the model could therefore be used to estimate the probability of generating intelligent life in our Universe, and in a multiverse scenario of hypothetical different universes.
The new research does not attempt to calculate the absolute number of observers (i.e. intelligent life) in the universe but instead considers the relative probability of a randomly chosen observer inhabiting a universe with particular properties.
Observations on Dark Energy
It concludes that a typical observer would expect to experience a substantially larger density of dark energy than is seen in our own Universe – suggesting the ingredients it possesses make it a rare and unusual case in the multiverse.
The approach presented in the paper involves calculating the fraction of ordinary matter converted into stars over the entire history of the Universe, for different dark energy densities.
The model predicts this fraction would be approximately 27 percent in a universe that is most efficient at forming stars, compared to 23 percent in our own Universe.
This means we don’t live in the hypothetical universe with the highest odds of forming intelligent life forms. Or in other words, the value of dark energy density we observe in our Universe is not the one that would maximize the chances of life, according to the model.
Dark Energy’s Impact on Our Existence
Lead researcher Dr. Daniele Sorini, of Durham University’s Institute for Computational Cosmology, said: “Understanding dark energy and the impact on our Universe is one of the biggest challenges in cosmology and fundamental physics.
“The parameters that govern our Universe, including the density of dark energy, could explain our own existence.
“Surprisingly, though, we found that even a significantly higher dark energy density would still be compatible with life, suggesting we may not live in the most likely of universes.”
Life and the Universe’s Expansion Dynamics
The new model could allow scientists to understand the effects of differing densities of dark energy on the formation of structures in the Universe and the conditions for life to develop in the cosmos.
Dark energy makes the Universe expand faster, balancing gravity’s pull and creating a universe where both expansion and structure formation are possible.
Exploring Life Across Different Universes
However, for life to develop, there would need to be regions where matter can clump together to form stars and planets, and it would need to remain stable for billions of years to allow life to evolve.
Crucially, the research suggests that the astrophysics of star formation and the evolution of the large-scale structure of the Universe combine in a subtle way to determine the optimal value of the dark energy density needed for the generation of intelligent life.
Professor Lucas Lombriser, Université de Genève and co-author of the study, added: “It will be exciting to employ the model to explore the emergence of life across different universes and see whether some fundamental questions we ask ourselves about our own Universe must be reinterpreted.”
Drake Equation Explained
Dr. Drake’s equation was more of a guide for scientists on how to go about searching for life, rather than an estimating tool or serious attempt to determine an accurate result.
Its parameters included the rate of yearly star formation in the Milky Way, the fraction of stars with planets orbiting them, and the number of worlds that could potentially support life.
By comparison, the new model connects the rate of yearly star formation in the Universe with its fundamental ingredients, such as the aforementioned dark energy density.
The study, which was funded by the European Research Council and also involved scientists at the University of Edinburgh and the Université de Genève, has been published today in Monthly Notices of the Royal Astronomical Society.
Reference: “The impact of the cosmological constant on past and future star formation” by Daniele Sorini, John A Peacock and Lucas Lombriser, 13 November 2024, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/stae2236
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.
2 Comments
In 1980, I took my school’s astronomy course. When discussing planetary formation in hypothetical solar systems, I commented, ” wouldn’t it be cool to find a gas giant the mass of Jupiter orbiting it’s host star about the radius of Mercury? ” My instructor said that couldn’t happen. ” How do you know? We haven’t yet found any planets outside of our solar system. ” At which point, he grabbed the chalk, went to the blackboard, and wrote down all the reasons WHY that couldn’t happen, including a bunch of nifty equations. As we scribbled all this info into our notes, I could see from the corners of my eyes all my friends giving me some nasty looks, and I knew what they were thinking: ” hey, you just gave us something else to study for on the big final! Thanks, buddy…! ” I’d give up my Mustang if I could go back in time to be there when he first heard about 51 Pegasus.
My point is, equations work when you have all possible information. When you don’t, all you have are educated guesses. Observations that challenge theory should not be addressed by inventing unicorn farts and pixie dust.
I was very curious when after reading this article I saw there was a single comment. I’m glad I decided to read it. It’s appropriately grounding, and sometimes I find myself in need of that when my head is in the stars. I love the mathematical models and theories, but it’s important to always keep in mind that every great mind that has ever existed thought they had the answer until next information surfaced that they couldn’t have fathomed even existed.