In addition to DESI, a number of new instruments are scheduled to come online in the coming years, including Chile’s 8.4-meter-tall Vera Rubin Observatory, NASA’s Nancy Grace Roman Space Telescope, and the European Space Agency’s Euclid Mission.
“Our data in cosmology have made great advances in the past 25 years, and we are on the verge of making even greater leaps forward,” Freeman said.
As researchers accumulate new observations, they may continue to discover that dark energy appears to be constant over generations. Or, if trends continue in the direction suggested by the DESI results, everything could change.
new physics
If dark energy is weakening, it cannot be a cosmological constant. Rather, it could be the same kind of field that many cosmologists believe triggered the moment of exponential expansion at the birth of the universe. This kind of “scalar field” fills space with an amount of energy that initially appears constant, like a cosmological constant, but eventually begins to decrease over time.
“The idea that dark energy is changing is very natural,” he said. paul steinhart, a cosmologist at Princeton University. Otherwise, it would become the only form of energy we know that is absolutely constant both in space and time. ” he continued.
But that volatility will cause a significant paradigm shift. We don’t live in a vacuum. lowest energy state of the universe. Instead, we end up living in an energized state that slowly slides toward a true vacuum. “We’re used to thinking of ourselves as living in a vacuum,” Steinhardt says. “But no one promised that.”
The fate of the universe will depend on how quickly and to what extent a value hitherto known as the cosmological constant decreases. When it reaches zero, the universe stops accelerating. If it drops far enough below zero, the expansion of the universe will turn into a slow contraction, the kind of reversal necessary for the universe. periodic theory of cosmologysuch as the one developed by Steinhardt.
String theorists have a similar view. Their proposal that everything comes down to the vibrations of a string allows us to weave together universes with varying numbers of dimensions and all kinds of exotic particles and forces.But those people not easy to build A universe that maintains a stable, positive energy forever, just like our universe. Instead, string theory requires that the energy either fall slowly over billions of years or fall sharply to zero or negative values. “Basically, all string theorists believe it’s one or the other. We don’t know which.” Qumrun Vafa of Harvard University.
Observational evidence of gradual decline in dark energy would be a boon for slow descent scenarios. “That’s amazing. It would be the most important discovery since the discovery of dark energy itself,” Vafa said.
But for now, such speculation is rooted in DESI analysis only in the loosest way. Cosmologists will need to observe millions more galaxies before seriously considering the revolution.
“If this holds up, it could open the way to new and potentially deeper understanding of the universe,” Rees said. “A lot should become clearer over the next few years.”
original story Reprinted with permission from Quanta Magazine, Editorially independent publication simmons foundation Its mission is to enhance the public’s understanding of science by covering research developments and trends in mathematics, physical sciences, and life sciences.
