UC Davis researchers have dated the earliest step in the formation of the solar system -- when microscopic interstellar dust coalesced into mountain-sized chunks of rock -- to 4,568 million years ago, within a range of about 2,080,000 years.
UC Davis postdoctoral researcher Frederic Moynier, Qing-zhu Yin, assistant professor of geology, and graduate student Benjamin Jacobsen established the dates by analyzing a particular type of meteorite, called a carbonaceous chondrite, which represents the oldest material left over from the formation of the solar system.
The physics and timing of this first stage of planet formation are not well understood, Yin said. So, putting time constraints on the process should help guide the physical models that could be used to explain it.
Showing posts with label Cosmology. Show all posts
Showing posts with label Cosmology. Show all posts
Friday, December 21, 2007
The Solar System's birthday discovered. More or less.
Science Daily:
Wednesday, October 31, 2007
Black holes are the hearts of galaxies
Which somehow sounds appropriate...
Washington Post:
Washington Post:
For years, astronomers speculated that a giant, mysterious force lay at the center of the Milky Way, but it wasn't until four years ago that UCLA astronomer Andrea Ghez definitively showed what it was.
Using new techniques for peering into the dusty heart of the galaxy, Ghez's observations proved that scores of stars were rapidly orbiting what could only be a black hole. But it wasn't the kind of garden-variety black hole created when a star explodes and dies; it was hundreds of thousands of times as powerful -- a "supermassive" black hole, as they are now known.
Her discoveries, along with the work of scientists studying other galaxies, have in a short time led researchers to the surprising conclusion that most, if not all, of the universe's hundreds of billions of galaxies have supermassive black holes at their core. Even more striking, the astronomers have found that the black holes' mass and nature are closely related to the size and makeup of the surrounding galaxies.
It also appears that these cosmic monsters -- which can "eat" stars whole -- are key to understanding how galaxies were formed and are still being formed today.
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