Astronomers using the Hubble Space Telescope say they have glimpsed the ultimate fate of the universe.
In what some are calling a landmark study, a team led by Adam Riess and Louis-Gregory Strolger said yesterday they have found the most reliable measure yet of the mysterious "dark energy" that's pushing everything in the universe apart.
Captured from the light of exploding stars, the data suggest that dark energy is pushing at a nearly constant rate, just as Albert Einstein predicted in 1920.
If those findings hold up, it means the universe will expand forever. Whatever galaxies, stars, planets and people are still around billions of years from now won't be ripped apart by runaway acceleration of that expansion - or crushed by its reversal into a "big crunch."
"This dark energy and cosmological acceleration are the deepest mystery in all science," said University of Chicago astrophysicist Michael S. Turner, who was not involved in the study. "This is the first time the measurements have been good enough to see whether or not the dark energy is changing with time ... I think it is a landmark."
Appeals for Hubble
Riess and other astronomers at the Space Telescope Science Institute in Baltimore immediately gave credit to Hubble, which faces an early retirement after a NASA decision to cancel its final servicing mission.
"The Hubble Space Telescope is the only tool able to peer far enough out in time and distance to observe these supernovae and track the rate of expansion of the universe over a large range of its history, and gauge the strength of dark energy," Riess said.
Neither the James Webb Space Telescope, scheduled for launch in 2011, nor the Spitzer Space Telescope, launched in August, can monitor the correct wavelengths, or scan a broad enough expanse of sky to search for the distant supernovae critical to measuring dark energy.
"Realistically, this problem will be with us for the next decade or two," Riess said. With Hubble expected to fail as early as 2007 if it's not serviced, he added, "I hope it isn't too long until there is some kind of dedicated telescope to do this kind of work."
Cosmologists, who study the origins, nature and fate of the universe, were startled in 1998 by the discovery that the expansion of the universe, which began with the Big Bang 13.7 billion years ago, was speeding up.
