Our universe does host life, but another one might be even better suited for life.
Here’s what you’ll learn when you read this story:
- Researchers are studying how hospitable our universe is to creating life. It’s related to the density of dark energy, which impacts star formation and the chances of life forming.
- The idea is that very few universes with intelligent life would have limited dark energy density. But ours is less than optimal.
- So, it’s puzzling that we exist, researchers said.
ublished in 1962 by American astronomer Frank Drake, Ph.D., the eponymous Drake equation sought to estimate the number of detectable alien civilizations in the Milky Way galaxy. This equation takes into account the average rate of star formation in the galaxy, the fraction of those stars that have orbiting planets, and the average number of those planets per star that can support life. It gets hairier: This formula also considers what fraction of those planets could support intelligent organisms, and whether those organisms can develop technology capable of contacting others.
Now, researchers in Switzerland and the U.K. have homed in on one particular aspect of this equation to contemplate how a crucial component of our universe affects star formation and, by extension, the possibility of intelligent life. Their paper studies the relationship between the density of a mysterious force in the universe, called dark energy, and the overall number of stars formed in the universe’s history. Published in November 2024 in the journal Monthly Notices of the Royal Astronomical Society, this work describes a new theoretical model of cosmic star formation applied to our universe as well as other possible ones with varying dark energy densities.
In other words, it ponders the likelihood of intelligent life existing in the multiverse.
To approach this question, the team tackled anthropic reasoning. This line of thinking is the idea that we can derive fundamental properties of the universe based on the fact that we exist. There’s so much we don’t know about the universe, but one thing we know for certain is that, at least in one tiny corner, it allows humans to exist. That starting point guides the way for understanding other characteristics of the universe.
Anthropic reasoning can offer explanations for the amount of dark energy in our universe. In the late 1980s, physics Nobel laureate Steven Weinberg used this idea to propose that the observed density of dark energy observed density of dark energy in the universe informs the existence of intelligent life within it. He contemplated that larger densities of dark energy would cause the universe to expand faster, negating gravity’s effort to clump matter together into galaxies, which would discourage star formation, and therefore, life.
Dark energy is an enigmatic force that may be causing the universe to expand at an accelerated rate. While it doesn’t explicitly factor into the Drake equation, dark energy does relate to star formation, which is key to the formula. In the same way that life on Earth wouldn’t exist without our sun, stars are a prerequisite for the formation of intelligent life. So, contemplating how varying amounts of dark energy in the universe impact star formation could tell us about other possible universes, too.
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