MSNBC - August 5, 2009
Stars in a distant galaxy move at stunning speeds — greater than 1 million mph, astronomers say.
These hyperactive stars move at about twice the speed of our sun through the Milky Way, because their host galaxy is very massive, yet strangely compact. The scene, which has theorists baffled, is 11 billion light-years away. It is the first time motions of individual stars have been measured in a galaxy so distant.
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Scientists used the new velocity measurements, conducted with the Gemini South telescope in Chile and the Hubble Space Telescope, to test the mass of a galaxy identified as 1255-0. The same way that the sun's gravity determines the orbiting speed of the Earth, the galaxy's gravity, and thus its mass, determines the velocities of the stars inside it.
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Tuesday, August 18, 2009
Rocking the cradle
The Economist - August 13, 2009
IN THE crazy world of Dr Seuss, an American children’s author, a bird called a Pelf lays eggs that are three times as big as herself. At this week’s meeting of the International Astronomical Union, astronomers were asked to entertain equally odd thoughts when they were presented with the latest evidence that some early galaxies, although smaller than their more recent counterparts, contain much more mass. It is like being handed a baby that weighs three times as much as its mother.
The objects in question are “red compact” galaxies, in particular a well-studied one called 1255-0 that formed just 3 billion years after the Big Bang. As the universe is thought to be 13.7 billion years old, the light reaching Earth from this galaxy shows what it was like some 10.7 billion years ago, when it was the equivalent of a newborn. Images suggest that the galaxy is 3,000 light years across—just a fifth of the size of the Earth’s home galaxy, the Milky Way—but about four times as massive.
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IN THE crazy world of Dr Seuss, an American children’s author, a bird called a Pelf lays eggs that are three times as big as herself. At this week’s meeting of the International Astronomical Union, astronomers were asked to entertain equally odd thoughts when they were presented with the latest evidence that some early galaxies, although smaller than their more recent counterparts, contain much more mass. It is like being handed a baby that weighs three times as much as its mother.
The objects in question are “red compact” galaxies, in particular a well-studied one called 1255-0 that formed just 3 billion years after the Big Bang. As the universe is thought to be 13.7 billion years old, the light reaching Earth from this galaxy shows what it was like some 10.7 billion years ago, when it was the equivalent of a newborn. Images suggest that the galaxy is 3,000 light years across—just a fifth of the size of the Earth’s home galaxy, the Milky Way—but about four times as massive.
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Monday, August 17, 2009
Mystery storm clouds on Saturn's largest moon appear
Los Anageles Times - August 14, 2009
At last, the missing storm clouds on Saturn's moon Titan may have been found.
In the last decade, researchers have monitored clouds at both of Titan's poles, where large lakes of methane have been spotted by Earth-based observers and by the Cassini spacecraft, which has been orbiting the moon for the last three years. But the moon's clouds seemed inexplicably confined to those areas.
"We've seen a lot of clouds at the poles. But we'd never seen a major storm at the equator," said Michael Brown, a professor of planetary astronomy at Caltech.
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In April 2008, Schaller was using NASA's Infrared Telescope Facility on Mauna Kea, Hawaii, to track daily weather activity on Titan. One day, after weeks of frustration, she checked the data from the previous night and found that "Titan suddenly had the biggest clouds ever."
After that, Brown, Schaller and their colleagues began tracking the clouds with the giant Gemini telescope on Mauna Kea. Brown said the first cloud appeared in the tropics and rapidly spread around the moon.
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At last, the missing storm clouds on Saturn's moon Titan may have been found.
In the last decade, researchers have monitored clouds at both of Titan's poles, where large lakes of methane have been spotted by Earth-based observers and by the Cassini spacecraft, which has been orbiting the moon for the last three years. But the moon's clouds seemed inexplicably confined to those areas.
"We've seen a lot of clouds at the poles. But we'd never seen a major storm at the equator," said Michael Brown, a professor of planetary astronomy at Caltech.
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In April 2008, Schaller was using NASA's Infrared Telescope Facility on Mauna Kea, Hawaii, to track daily weather activity on Titan. One day, after weeks of frustration, she checked the data from the previous night and found that "Titan suddenly had the biggest clouds ever."
After that, Brown, Schaller and their colleagues began tracking the clouds with the giant Gemini telescope on Mauna Kea. Brown said the first cloud appeared in the tropics and rapidly spread around the moon.
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Friday, August 14, 2009
Scientists discover storms in the tropics of Titan
Astronomy.com - August 13, 2009
For all its similarities to Earth-clouds that pour rain — albeit liquid methane not liquid water — onto the surface producing lakes and rivers, vast dune fields in desert-like regions, plus a smoggy orange atmosphere, Saturn's largest moon, Titan, is generally "a very bland place," according to Mike Brown of the California Institute of Technology (Caltech).
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The day after the telescope's big find, Schaller, Brown, and Roe began tracking the clouds with the large Gemini telescope on Mauna Kea and watched this system evolve for a month. "And what a cool show it was," Brown said.
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For all its similarities to Earth-clouds that pour rain — albeit liquid methane not liquid water — onto the surface producing lakes and rivers, vast dune fields in desert-like regions, plus a smoggy orange atmosphere, Saturn's largest moon, Titan, is generally "a very bland place," according to Mike Brown of the California Institute of Technology (Caltech).
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The day after the telescope's big find, Schaller, Brown, and Roe began tracking the clouds with the large Gemini telescope on Mauna Kea and watched this system evolve for a month. "And what a cool show it was," Brown said.
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Thursday, August 13, 2009
Methane Clouds Observed Near Titan's Equator May Explain Presence of Riverbeds on the Surface
U.S. News & World Report - August 13, 2009
On Titan, Saturn's largest moon, methane clouds drift through a dense, nitrogen-rich atmosphere, clustering mainly in the polar regions. Methane lakes dot Titan's surface, also at high latitudes. Closer to the moon's equator, by contrast, clouds appear rarely if at all, and the surface seems arid. But in January 2005, the Huygens probe, after detaching from the Cassini spacecraft and descending through Titan's atmosphere, gave planetary scientists their first close-up view of the moon's surface. Huygens imaged small channels and river beds at low latitudes, in regions that scientists had assumed to be devoid of flowing liquids that could carve such features. Now, astronomers working at Earth-based telescopes have for the first time observed, near Titan's equator, large and persistent clouds that might be capable of raining liquid methane onto the surface.
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At visible wavelengths, Titan's hazy atmosphere—whose surface pressure is about one and half times that of Earth's—gives it a fuzzy, opaque appearance. At certain infrared wavelengths, however, the atmosphere is transparent while methane clouds are highly reflective. Schaller and her colleagues used NASA's Infrared Telescope Facility (IRTF), situated on Hawaii's Mauna Kea, to check Titan's infrared brightness as many nights as they could. IRTF measures the brightness of Titan as a whole, so when it revealed an increase in infrared reflectivity, the team turned to another telescope, Gemini North, to see where on Titan that infrared light was coming from. Gemini North, also on Mauna Kea, is one of a pair of 8-meter infrared telescopes funded in part by the National Science Foundation; its twin is Gemini South in the Chilean Andes. The Gemini telescopes achieve high resolution through the use of adaptive optics, meaning that the shape of their mirrors can be rapidly tweaked to overcome the blurring of images that results from light passing through the Earth's turbulent atmosphere.
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On Titan, Saturn's largest moon, methane clouds drift through a dense, nitrogen-rich atmosphere, clustering mainly in the polar regions. Methane lakes dot Titan's surface, also at high latitudes. Closer to the moon's equator, by contrast, clouds appear rarely if at all, and the surface seems arid. But in January 2005, the Huygens probe, after detaching from the Cassini spacecraft and descending through Titan's atmosphere, gave planetary scientists their first close-up view of the moon's surface. Huygens imaged small channels and river beds at low latitudes, in regions that scientists had assumed to be devoid of flowing liquids that could carve such features. Now, astronomers working at Earth-based telescopes have for the first time observed, near Titan's equator, large and persistent clouds that might be capable of raining liquid methane onto the surface.
...
At visible wavelengths, Titan's hazy atmosphere—whose surface pressure is about one and half times that of Earth's—gives it a fuzzy, opaque appearance. At certain infrared wavelengths, however, the atmosphere is transparent while methane clouds are highly reflective. Schaller and her colleagues used NASA's Infrared Telescope Facility (IRTF), situated on Hawaii's Mauna Kea, to check Titan's infrared brightness as many nights as they could. IRTF measures the brightness of Titan as a whole, so when it revealed an increase in infrared reflectivity, the team turned to another telescope, Gemini North, to see where on Titan that infrared light was coming from. Gemini North, also on Mauna Kea, is one of a pair of 8-meter infrared telescopes funded in part by the National Science Foundation; its twin is Gemini South in the Chilean Andes. The Gemini telescopes achieve high resolution through the use of adaptive optics, meaning that the shape of their mirrors can be rapidly tweaked to overcome the blurring of images that results from light passing through the Earth's turbulent atmosphere.
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Titan 'put on quite a show'
Honolulu Advertiser - August 13, 2009
A paper written by a University of Hawai'i researcher that describes the first storm observed in the tropical latitudes of Saturn's moon Titan will be published today in the journal Nature.
The paper's lead author, Dr. Emily Schaller, wrote it while working as a Hubble Fellow at the University of Hawai'i-Manoa's Institute for Astronomy.
The paper says that rain from large clouds such as those observed on Titan is actually liquid methane and may be responsible for forming the channels and other features near the equator observed by the Huygens probe in 2005.
The huge storm — observed with the NASA Infrared Telescope Facility and the Gemini North telescope on Mauna Kea — covered almost 1.2 million square miles, an area about the size of India.
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A paper written by a University of Hawai'i researcher that describes the first storm observed in the tropical latitudes of Saturn's moon Titan will be published today in the journal Nature.
The paper's lead author, Dr. Emily Schaller, wrote it while working as a Hubble Fellow at the University of Hawai'i-Manoa's Institute for Astronomy.
The paper says that rain from large clouds such as those observed on Titan is actually liquid methane and may be responsible for forming the channels and other features near the equator observed by the Huygens probe in 2005.
The huge storm — observed with the NASA Infrared Telescope Facility and the Gemini North telescope on Mauna Kea — covered almost 1.2 million square miles, an area about the size of India.
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A Tropical Tempest on Titan
Sky & Telescope - August 12, 2009
There's an old saying that describes the weather in Maine as "9 months of wintah, and 3 months of damn poor sleddin'." But even the hardiest Mainer would be challenged by the climate on Saturn's big moon Titan, where "wintah" lasts 7½ years, temperatures struggle to reach -290°F (-178°C), the ground is rock-hard water ice, and a mix of liquid methane and ethane rains from the sky.
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An observing team led by Emily Schaller (University of Hawaii) and Henry Roe (Lowell Observatory) has been keeping very close tabs on Titan's weather. In fact, Schaller's Caltech doctoral thesis hinged on analyzing the moon's long-term climatic characteristics. Using a sensitive spectrometer with NASA's 3-meter Infrared Telescope Facility on Mauna Kea, the team set up a long-running "storm watch" — 138 nights over 2.2 years — for signs of sporadic methane-cloud buildups, as had occurred in 1995 and 2004. Whenever it looked like a storm might be brewing, the observers switched to an infrared imager on the much larger Gemini North telescope, also on Mauna Kea.
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There's an old saying that describes the weather in Maine as "9 months of wintah, and 3 months of damn poor sleddin'." But even the hardiest Mainer would be challenged by the climate on Saturn's big moon Titan, where "wintah" lasts 7½ years, temperatures struggle to reach -290°F (-178°C), the ground is rock-hard water ice, and a mix of liquid methane and ethane rains from the sky.
...
An observing team led by Emily Schaller (University of Hawaii) and Henry Roe (Lowell Observatory) has been keeping very close tabs on Titan's weather. In fact, Schaller's Caltech doctoral thesis hinged on analyzing the moon's long-term climatic characteristics. Using a sensitive spectrometer with NASA's 3-meter Infrared Telescope Facility on Mauna Kea, the team set up a long-running "storm watch" — 138 nights over 2.2 years — for signs of sporadic methane-cloud buildups, as had occurred in 1995 and 2004. Whenever it looked like a storm might be brewing, the observers switched to an infrared imager on the much larger Gemini North telescope, also on Mauna Kea.
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Atmospheric 'pulse' may spread rain clouds across Titan
New Scientist - August 12, 2009
A pulse in the atmosphere of Saturn's moon Titan can spawn methane clouds across the moon, new observations suggest. Although the cause of such atmospheric events is still unknown, it could explain some puzzling features seen by the only probe ever to land on Titan's surface.
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Now Brown and colleagues have found a possible explanation. The team spotted a vast cloud below Titan's equator that triggered cloud formation in regions across the southern hemisphere. Such events might be a way to deliver methane rain to arid regions like the Huygens landing site, which sits some 10° south of the equator. "We think that this is an important part of the story," Brown says.
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The team found that Titan appeared brighter on 13 April 2008, and on the following night, Mauna Kea's 8-metre Gemini North telescope revealed a large cloud centred some 30° south of Titan's equator.
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Tropical storm spotted on Saturn's moon Titan
MSNBC - August 12, 2009
A tropical storm was not what astronomers expected to see when they pointed their telescopes toward the equator of Saturn's moon Titan last summer.
But that's exactly what they found on this beguiling moon, home to a weather system both eerily familiar and perplexingly strange. The discovery was announced today.
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Clouds of vaporized methane are not uncommon on Titan, though they have never before been observed in Titan's tropics. But in April 2008, astronomers using the Gemini North telescope and NASA's Infrared Telescope Facility in Hawaii spotted a severe storm covering almost 2 million square miles (3 million square km) over the equator.
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Thursday, August 6, 2009
Hubble, Gemini Spot 'Hyperactive' Stars in Small, Young Galaxies
Universe Today - August 5, 2009
We all know youngsters are a handful, but this really takes the cake: astronomers have clocked the speeds of stars in infant galaxies at about a million miles an hour, about twice the pace of our Sun's cruise through the Milky Way.
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Researchers spotted the galaxies with NASA’s Hubble Space Telescope and the 8-meter Gemini South telescope in Chile. Hubble revealed that the galaxies are a fraction the size of most galaxies we see today, and Gemini clocked their speed by using spectroscopy.
The Gemini near-infrared spectroscopic observations required an extensive 29 hours on the sky to collect the extremely faint light from the distant galaxy, which goes by the designation 1255-0.
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We all know youngsters are a handful, but this really takes the cake: astronomers have clocked the speeds of stars in infant galaxies at about a million miles an hour, about twice the pace of our Sun's cruise through the Milky Way.
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Researchers spotted the galaxies with NASA’s Hubble Space Telescope and the 8-meter Gemini South telescope in Chile. Hubble revealed that the galaxies are a fraction the size of most galaxies we see today, and Gemini clocked their speed by using spectroscopy.
The Gemini near-infrared spectroscopic observations required an extensive 29 hours on the sky to collect the extremely faint light from the distant galaxy, which goes by the designation 1255-0.
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Jupiter smash: even more pictures - July 27, 2009
Nature.com - July 27, 2009
More pictures have emerged of the collision that gave Jupiter a new scar earlier this month.
The new scar is believed to have resulted from a comet slamming into the planet. After being spotted by Australian amateur astronomer Anthony Wesley (first picture) it was imaged by two telescopes on Mauna Kea in Hawaii (second pictures).
Now a third telescope on Mauna Kea and, most excitingly, the Hubble Space Telescope have focused in on the impact site. Here are the shots from them both (Gemini Observatory right, Hubble left)...
More pictures have emerged of the collision that gave Jupiter a new scar earlier this month.
The new scar is believed to have resulted from a comet slamming into the planet. After being spotted by Australian amateur astronomer Anthony Wesley (first picture) it was imaged by two telescopes on Mauna Kea in Hawaii (second pictures).
Now a third telescope on Mauna Kea and, most excitingly, the Hubble Space Telescope have focused in on the impact site. Here are the shots from them both (Gemini Observatory right, Hubble left)...