As it turns out, our universe seems to get it just about right. The existing cosmological constant means the rate of expansion is large enough that it minimizes planets’ exposure to gamma ray bursts, but small enough to form lots of hydrogen-burning stars around which life can exist. (A faster expansion rate would make it hard for gas clouds to collapse into stars.)
Jimenez says the expansion of the universe played a bigger role in creating habitable worlds than he expected. “It was surprising to me that you do need the cosmological constant to clear out the region and make it more suburbanlike,” he says.
Beyond what they reveal about the potential for life in our galaxy and beyond, the findings offer a new nugget of insight into one of the biggest puzzles in cosmology: why the cosmological constant is what it is, says cosmologist Alan Heavens, director of the Imperial Centre for Inference and Cosmology at Imperial College London.
In theory, Heavens explains, either the constant should be hundreds of orders of magnitude higher than it appears to be, or it should be zero, in which case the universe wouldn’t accelerate. But this would disagree with what astronomers have observed. “The small—but nonzero—size of the cosmological constant is a real puzzle in cosmology,” he says, adding that the research shows the number is consistent with the conditions required for the existence of intelligent life that is capable of observing it.More.
See also: Copernicus, you are not going to believe who is using your name. Or how.
What we know and don’t, know about the origin of life
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