Astronomers announced Friday that they had found strong new evidence that a theory Albert Einstein proposed but later discarded may have been right after all, providing crucial new clues to the fundamental nature and eventual fate of the cosmos.
A detailed analysis of light from ancient exploding stars has yielded powerful support for the idea that recently discovered "dark energy" that pervades the universe might be what Einstein originally dubbed the "cosmological constant." If confirmed, the findings support theories that the cosmos will continue its slow expansion toward nothingness instead of violently ripping apart or collapsing, astronomers said.
The results were hailed as pivotal new data that will help answer the most pressing and profound questions about the universe, such as what makes up most of the void and what eventually will happen to it.
"I think it’s incredible," said John Bahcall of the Institute of Advanced Study in Princeton, N.J. "What it is that currently drives the expansion of the universe — that’s the burning question today."
"It’s an important step toward getting a consistent picture of how our universe is expanding," said Martin Rees, a cosmologist at the University of Cambridge in England. "It’s corroborating the rather surprising picture that this dark energy pervades all of empty space."
Astronomers startled the scientific world in 1998 when they announced that they had discovered that most of the universe consists of a previously unknown force they dubbed dark energy, which was causing the universe to expand at an accelerating rate. The existence of the energy was later confirmed, but its nature remained a mystery, prompting a flurry of research to discern its identity and develop theories to explain it.
"Dark energy and the nature of dark energy is probably the biggest problem that physics is facing today," said Mario Livio of the Space Telescope Science Institute in Baltimore, who helped conduct the research. "Imagine that we know that a large fraction of the surface of Earth is covered with water. Imagine if we didn’t know what it was that is covering the surface of Earth. That’s the situation that we are in."
In the new work, led by Adam Riess of the Space Telescope Science Institute, researchers used the orbiting Hubble telescope to measure various properties of light emitted by 16 exploding stars, known as supernovas. Because the stars are at various distances from Earth, they yield information about what was happening at different points in the past. The supernovas included six of the seven most distant supernovas ever studied, dating two-thirds of the way back to the Big Bang.
"This is sort of like a time machine," Riess said. "By finding them at different distances, we can look at different times in the universe and we can ask how fast the universe was expanding then. It’s like looking at tree rings to get a glimpse back in history."
In a paper to be published in the Astrophysical Journal, the researchers concluded that the strength of dark energy was consistent with Einstein’s predicted cosmological constant, and that it appeared fairly consistent over time, also as Einstein had theorized. The researchers said they were now twice as confident as they were before that dark energy is consistent with Einstein’s idea.
"It looks like Einstein may turn out to have been right after all," Riess said.
"The simplest assumption is that the universe will become ever darker, and ever emptier, as the galaxies recede from us," the University of Cambridge’s Rees said. "And in the very far future there will be nothing in evidence. Everything will have disappeared beyond the horizon."
Talk to us
> Give us your news tips.
> Send us a letter to the editor.
> More Herald contact information.
