Scientists are in the nature of a mysterious force called dark energy, and nothing less than the fate of the universe hangs in balance.
The force is huge: it represents almost 70% of the universe. And it is powerful: it is moving away to all the stars and galaxies of each other at an increasingly fast pace.
And now scientists are getting a little closer to understand how it behaves. The big question is whether this dark energy is a constant force, that scientists have thought for a long time, or if the force is weakening, a surprising wrinkles settled tentatively last year.
The results presented at a meeting of the American Physical Society Wednesday reinforce the case that the force is weakening, although scientists are not yet safe and have not yet resolved what this means for the rest of their understanding of the universe.
Updated findings come from an international research collaboration that is creating a three -dimensional map to see how galaxies have extended and grouped for 11 billion years in the history of the universe. Carefully track how galaxies moves helps scientists learn about the forces that are moving them.
Called the spectroscopic instrument of dark energy, the collaboration launched its first analysis of 6 million galaxies and quasars last year and has now added more data, which leads the count to almost 15 million. Its updated results, taken with other measures (explosive stars, leftover light of the young universe and distortions in the form of galaxy) support the idea presented last year that dark energy can be decreasing.
“He is moving from a really surprising finding at almost a moment in which we have to rule out how we have thought about cosmology and start over,” said Bhuvnesh Jain, a cosmologist at the University of Pennsylvania who was not involved with the investigation.
It is not time to completely rule out the idea that dark energy is constant because the new results are still shy with the standard level of gold of the statistical test that physics requires. The collaboration aims to assign around 50 million galaxies and quasars at the end of their survey in 2026. And other efforts worldwide have an eye on dark energy and aim to free their own data in the coming years, including the Euclid mission of the European Space Agency and the Vera C. Rubin Observatory in Chile.
“We want to see several different collaborations that have similar measurements” in that gold standard to make sure that dark energy is weakening, said cosmologist Kris Pardo of the University of Southern California that did not participate in the new research.
If dark energy is constant, scientists say that our universe can continue to expand forever, more and more cold, more lonely and even.
If dark energy is reduced over time, which now seems plausible, the universe could someday stop expanding and then finally collapse on what is called Big Crunch. It may not seem the most cheerful destination, but it offers some closure, said the cosmologist and collaborator of Mustapha Ishak-Boushaki studies of the University of Texas in Dallas.
“Now, there is the possibility that everything comes to an end,” he said. “Would we consider something good or bad? I don’t know.”
