Universe

Caltech physicist Sean M. Carroll has been wrestling with the mystery of time. Most physical laws work equally well going backward or forward, yet time flows only in one direction. Writing in this month's Scientific American, Carroll suggests that entropy, the tendency of physical systems to become more disordered over time, plays a crucial role. Carroll sat down recently at Caltech to explain his theory. What's the problem with time?

Google has already planted its flag on Earth, the moon and Mars. The universe could be next. The Internet search company has struck a partnership with scientists building a huge sky-scanning telescope, with hopes of helping the public gain access to digital footage of asteroids, supernovas and distant galaxies. "Frankly, I could see the day when they would be our sort of window to the general public," said Donald Sweeney, manager of the Large Synoptic Survey Telescope, or LSST.

Dark matter is like a construction scaffold on a building, allowing visible matter to build stars and galaxies, according to the first three-dimensional map of the unseen stuff that is thought make up the majority of mass in the universe. The map, created with images from the Hubble Space Telescope, confirms theories that dark matter accumulates in the same regions as visible matter, giving it a kind of shell, or exoskeleton, to work within.

The world's leading center for research into the origins of matter has taken a giant step toward a 15-year experiment that could unlock secrets of the universe. A 1,920-ton magnet, the equivalent of five jumbo jets, was lowered Wednesday into an underground cavern at the multinational center, CERN, on the Swiss-French border near Geneva.

A team of scientists says it has found the most convincing evidence so far that the mysterious stuff known as dark matter really exists: a gigantic ring of invisible material left over from the ancient collision of galaxy clusters. Researchers using the Hubble Space Telescope stumbled on the ring -- about 2.6 million light-years across -- while studying the galaxy cluster CI 0024+17, which is about 5 billion light-years from Earth.

The universe has a gargantuan hole devoid of galaxies, stars, even dark matter, astronomers said Thursday. The University of Minnesota researchers said the void is nearly a billion light-years across and they had no idea why it is there. "Not only has no one ever found a void this big, but we never even expected to find one this size," said astronomy professor Lawrence Rudnick.

NASA's Dawn spacecraft launched Thursday on a 3.2-billion-mile journey to the asteroid belt, where scientists hope to find clues to the formation of the solar system. The spacecraft, atop a Delta 2 rocket, took off from Cape Canaveral in Florida at 4:34 a.m. PDT. "We have our time machine up and flying," said UCLA space physics professor Christopher T. Russell, the lead scientist on the project. Scientists at the Jet Propulsion Laboratory in La Ca?

John D. Barrow, a Cambridge University cosmologist who has researched and written extensively about the relationship between life and the universe, on Wednesday was awarded the 2006 Templeton Prize, worth about $1.4 million, for progress in spiritual knowledge. Barrow, 53, a professor of mathematical sciences who once held research fellowships in astronomy and physics at UC Berkeley, is the sixth scientist to win the award, considered the Nobel Prize for religion.

Physicists announced Thursday that they now have the smoking gun that shows the universe went through extremely rapid expansion in the moments after the big bang, growing from the size of a marble to a volume larger than all of observable space in less than a trillion-trillionth of a second.

Cosmic nebulae usually look like blobs in space, but astronomers using NASA's Spitzer Space Telescope reported Wednesday that they had found a nebula twisted like the double helix of DNA. "Nobody has ever seen anything like that before in the cosmic realm," said astronomer Mark Morris of UCLA. Most nebulae are "formless, amorphous conglomerations of dust and gas," he said in a statement, adding that this one "indicates a high degree of order."