Astronomers go planet hunting
By Kate Lunau - Tuesday, January 22, 2013 - 0 Comments
New research suggests our galaxy alone may be filled with billions of planets—literally
Use your cursor to scroll over the planets above.
Just 20 years ago, astronomers didn’t know if there were any planets at all outside our own solar system—whether other places like Earth, which is brimming with life, are common, exceedingly rare or even non-existent. Two years ago, NASA scientists announced that, using the powerful Kepler space telescope, they’d found well over 1,000 new planets, more than doubling the number they’d previously known about. It was a stunning revelation, but few people realized, even then, that this was just the beginning.
Astronomers now believe our galaxy alone is filled with literally billions of planets—maybe even more planets than stars. There are at least 100 billion planets in the Milky Way, and some think that estimate is conservative. Some are more bizarre than anything dreamed up in science fiction: diamond worlds and double-sunned worlds, and worlds where another planet hangs in the sky like our moon. Others are eerily similar to Earth. A few of them, like a newly found planet orbiting Alpha Centauri, just 4.3 light years away, are tantalizingly close. That planet is nearer to its host star than Mercury is to our sun, and would be blisteringly hot—far too hot for life as we know it. But where there’s one planet, there are often several, and astronomers are scouring the skies around Alpha Centauri for more worlds in our own cosmic backyard. Continue…
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Cosmic stardust detectives
By Kate Lunau - Thursday, April 1, 2010 at 9:00 AM - 3 Comments
Scientists may have a first—stardust—thanks to a Canadian
Photograph by Reuters
We’re all made of stardust, Joni Mitchell once sang, and technically, she was right. Like giant nuclear ovens, stars cook up almost all of the elements in the periodic table, expelling them after the star’s death. A stream of this interstellar dust, which makes up our homes, cars, even our bodies, flows through space. For the first time, scientists say they may have recovered some, with the help of one Canadian space buff.
Back in 1999, NASA’s Stardust spacecraft was launched. Shaped a bit like a tennis racket, this collector was outfitted with blocks of aerogel—a ghostly blue-white material, similar to glass but only a few times denser than air, in which particles bury themselves upon impact. The Stardust mission was designed to fetch samples from an ancient comet containing the “best-preserved samples of the building blocks of our solar system,” says Don Brownlee, a cosmic dust expert at the University of Washington, its principal investigator. “As a bonus,” he says, “we used the backside of the collector to gather dust flowing in from the galaxy.” The Stardust collector returned to earth in 2006, bringing the first solid samples ever retrieved from beyond the moon.
In the lab, comet particles were easy enough to find, Brownlee says; visible to the naked eye, they leave long tracks in aerogel “like hollow carrots.” But tiny interstellar dust particles are another story. Researchers considered making a computer program to seek them out, but soon noticed that people—even untrained ones—did better. Inspired by other crowdsourcing efforts, Andrew Westphal of the University of California, Berkeley created Stardust@home, an Internet application where the public could sift through images of aerogel for signs of interstellar dust tracks. Since it was launched in 2006, more than 27,000 people (so-called “dusters”) joined in, completing over 71 million searches. Altogether, 28 tracks have been found.
