Everybody can breathe easier: The universe won't collapse on itself in a "big crunch" billions of years from now, scientists said Wednesday.
Instead, the universe will expand forever, ever faster, fueled by a mysterious, "dark" form of energy, a new study found. The work confirms many fundamental predictions of cosmology, including the shape of the universe and how it was born in a "big bang" about 10 billion to 15 billion years ago.
Astronomers unveiled the most detailed images yet of the baby universe at a Washington, D.C., news conference. The research also appears in Thursday's issue of the journal Nature.
"These are literally snapshots of what the universe looked like when it was just a few hundred thousand years old," said Andrew Lange, an astrophysicist at the California Institute of Technology in Pasadena.
Dr. Lange, with Paolo de Bernardis of the University of Rome, led an international research team that studied physical remnants of the big bang. The remnants offer a glimpse of the universe when it was just a fraction of its current age.
The scientists attached $4 million of equipment and a telescope to a balloon, then set it aloft over Antarctica in December 1998. The telescope, called BOOMERANG (for Balloon Observations of Millimetric Extragalactic Radiation and Geophysics ), drifted at 120,000 feet for nearly 11 days. It stared at a tiny region of the sky, measuring the temperature of microwave radiation there.
The universe is filled with a faint microwave glow - remnant energy from the big bang. The glow is everywhere, including your TV set, where it accounts for a small fraction of the "snow" seen between channels. For astronomers, measuring the microwaves uncovers details of the early universe, such as the distribution of matter lumps that later grew into galaxies and other large structures.
Although other balloon and ground-based experiments have reached roughly the same conclusions, BOOMERANG is the most detailed study yet of the microwave glow, Dr. Lange said. The telescope spotted tiny temperature variations across the sky, confirming recent theories about what the universe is made of and what its ultimate fate might be.
"The BOOMERANG results fit the new cosmology like a glove," said Michael Turner, an astronomer at the University of Chicago who was not involved in the experiment.
Most importantly, he said, the temperature data confirm that the universe is "flat." That means, in cosmological terms, that it can be described with ordinary three-dimensional geometry, the type used in high school, rather than complicated versions introduced by Albert Einstein.
Astronomers had suspected that the universe is flat, but now they can be sure, Dr. Turner said. And a flat universe will always have the right balance of matter and energy to keep it from collapsing in a big crunch.
The work also supports two other popular theories, he added. One is that the universe grew enormously in size, very quickly, about a minute after it was born. The second is that the universe is permeated with a kind of "dark energy," a poorly understood phenomenon that is thought to keep the universe from collapsing.
For more information and images, visit the World Wide Web site www.physics.ucsb.edu/ ~boomerang.