Science & TechnologyS


Nebula

Black hole spins at nearly the speed of light

Andrew Fazekas
National Geographic
Fri, 01 Mar 2013 08:20 UTC
Image
© Illustration courtesy Caltech/NASAAn artist's concept illustrates a supermassive black hole with millions to billions times the mass of our sun.
A superfast black hole nearly 60 million light-years away appears to be pushing the ultimate speed limit of the universe, a new study says.

For the first time, astronomers have managed to measure the rate of spin of a supermassive black hole - and it's been clocked at 84 percent of the speed of light, or the maximum allowed by the law of physics.

"The most exciting part of this finding is the ability to test the theory of general relativity in such an extreme regime, where the gravitational field is huge, and the properties of space-time around it are completely different from the standard Newtonian case," said lead author Guido Risaliti, of the Harvard-Smithsonian Center for Astrophysics (CfA) and INAF-Arcetri Observatory in Italy.

Notorious for ripping apart and swallowing stars, supermassive black holes live at the center of most galaxies, including our own Milky Way.

They can pack the gravitational punch of many million or even billions of suns - distorting space-time in the region around them, not even letting light escape their clutches.
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Info

Human Y chromosome much older than previously thought

Daniel Stolte
University of Arizona
Fri, 01 Mar 2013 21:22 UTC
Y Chromosome
© University of ArizonaHuman sex-determining chromosomes: X chromosome (left) and the much smaller Y chromosome.
The discovery and UA analysis of an extremely rare African American Y chromosome pushes back the time of the most recent common ancestor for the Y chromosome lineage tree to 338,000 years ago. This time predates the age of the oldest known anatomically modern human fossils.

Human sex-determining chromosomes: X chromosome (left) and the much smaller Y chromosome. UA geneticists have discovered the oldest known genetic branch of the human Y chromosome - the hereditary factor determining male sex. The new divergent lineage, which was found in an individual who submitted his DNA to Family Tree DNA, a company specializing in DNA analysis to trace family roots, branched from the Y chromosome tree before the first appearance of anatomically modern humans in the fossil record.

The results are published in the American Journal of Human Genetics.
"Our analysis indicates this lineage diverged from previously known Y chromosomes about 338,000 ago, a time when anatomically modern humans had not yet evolved," said Michael Hammer, an associate professor in the University of Arizona's department of ecology and evolutionary biology and a research scientist at the UA's Arizona Research Labs. "This pushes back the time the last common Y chromosome ancestor lived by almost 70 percent."
Unlike the other human chromosomes, the majority of the Y chromosome does not exchange genetic material with other chromosomes, which makes it simpler to trace ancestral relationships among contemporary lineages. If two Y chromosomes carry the same mutation, it is because they share a common paternal ancestor at some point in the past. The more mutations that differ between two Y chromosomes the farther back in time the common ancestor lived.
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Comet 2

Update on the comet that might hit Mars

Nancy Atkinson
Universe Today
Tue, 05 Mar 2013 18:38 UTC

The latest trajectory of comet 2013 A1 (Siding Spring) generated by the Near-Earth Object Program Office at the Jet Propulsion Laboratory indicates the comet will pass within 186,000 miles (300,000 kilometers) of Mars and there is a strong possibility that it might pass much closer. The NEO Program Office's current estimate based on observations through March 1, 2013, has it passing about 31,000 miles (50,000 kilometers) from the Red Planet's surface. That distance is about two-and-a-half times that of the orbit of outermost moon, Deimos.

Previous estimates put it on a possible collision course with Mars.

This video, above, is based on comet's orbit calculated by Leonid Elenin, which has it is coming within 58,000 km, and visualized by SpaceEngine software.
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Fireball 4

USGS confirms Iowa town built on top of meteorite crater

Kelly Maricle
whotv.com
Tue, 05 Mar 2013 16:24 UTC
The U.S. Geological Survey has confirmed the northeast Iowa town of Decorah is built on top of a meteorite crater created 470 million years ago. Iowa Department of Natural Resources geologists first suspected the area was a meteorite crater in 2008 after studying well drill-cuttings and finding a unique type of shale. Shocked quartz was also found, which is considered strong evidence of a meteorite impact.

Recent airborne geophysical surveys included an airborne electromagnetic system, which can detect how well rocks conduct electricity. The data showed the crater was filled with electrically conductive shale.
Image
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Telescope

Rare photos capture 2 comets together in night sky

Nina Sen
SPACE.com
Tue, 05 Mar 2013 15:45 UTC
Comets Pan-STARRS Lemmon
© Yuri BeletskyYuri Beletsky, a Magellan Instrument Support Scientist at Las Campanas observatory located in Atacama Desert in Chile, used a Canon 5D Mark II camera with an exposure time of ~ 30 seconds on Feb. 28, 2013 to capture this image of Comets Pan-STARRS and Lemmon.
Two comets are putting on an amazing night sky show this month and some intrepid photographers have captured rare views of both celestial objects at the same time.

The photos of Comet Pan-STARRS and Comet Lemmon were taken by veteran space photographers in Chile and Australia in late February. At the time, both comets were visible from the Southern Hemisphere, though Comet Pan-STARRS is set to become visible from the Northern Hemisphere later this week.

One of the double-comet photos was taken by Yuri Beletsky, a Magellan Instrument Support Scientist at Las Campanas Observatory located in the Atacama Desert of Chile. Beletsky is an accomplished space photographer and used a Canon 5D Mark II camera with an exposure time of about 30 seconds on Feb. 28 to capture the rare sight of the two comets together.
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Telescope

Potential 2014 Mars Collision of New Comet C/2013 A1 Siding Spring Explained

Joe Rao
SPACE.com
Mon, 04 Mar 2013 15:35 UTC
comet C/2013 A1 Siding Spring
© NASA/JPLThis NASA diagram shows the location and estimated orbit of comet C/2013 A1 (Siding Spring), discovered on Jan. 3, 2013, by astronomer Robert McNaught.
A newfound comet is apparently on course to have an exceedingly close call with the planet Mars in October 2014, and there is a chance - albeit small - that the comet may even collide with the Red Planet.

The new comet C/2013 A1 (Siding Spring) was discovered Jan. 3 by the Scottish-Australian astronomer Robert H. McNaught, a prolific observer of both comets and asteroids who has 74 comet discoveries to his name.

McNaught is a participant in the Siding Spring Survey a program that hunts down asteroids that might closely approach the Earth. He discovered the new comet using the 0.5-meter Uppsala Schmidt Telescope at Siding Spring Observatory, New South Wales, Australia.
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Comet 2

Evidence that comets could have seeded life on Earth

Robert Sanders
News Center
Tue, 05 Mar 2013 14:00 UTC
Image
© NASAComets like Halley’s can be a breeding ground for complex molecules such as dipeptides. Comets colliding with Earth could have delivered these molecules and seeded the growth of more complex proteins and sugars necessary for life.
A new experiment simulating conditions in deep space reveals that the complex building blocks of life could have been created on icy interplanetary dust and then carried to Earth, jump-starting life.

Chemists from the University of California, Berkeley, and the University of Hawaii, Manoa, showed that conditions in space are capable of creating complex dipeptides - linked pairs of amino acids - that are essential building blocks shared by all living things. The discovery opens the door to the possibility that these molecules were brought to Earth aboard a comet or possibly meteorites, catalyzing the formation of proteins (polypeptides), enzymes and even more complex molecules, such as sugars, that are necessary for life.

"It is fascinating to consider that the most basic biochemical building blocks that led to life on Earth may well have had an extraterrestrial origin," said UC Berkeley chemist Richard Mathies, coauthor of a paper published online last week and scheduled for the March 10 print issue of The Astrophysical Journal.

While scientists have discovered basic organic molecules, such as amino acids, in numerous meteorites that have fallen to Earth, they have been unable to find the more complex molecular structures that are prerequisites for our planet's biology. As a result, scientists have always assumed that the really complicated chemistry of life must have originated in Earth's early oceans.
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Sherlock

Giant camel fossil found in Arctic

Rebecca Morelle
BBC News
Tue, 05 Mar 2013 14:08 UTC
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The giant camels were thought to have lived about 3.5 million years ago and are believed to be direct ancestors of our modern species
Camels are well known for their ability to survive the hot and dry conditions of the desert, but a study suggests they once thrived in colder climes. Scientists have unearthed the fossilised remains of a giant species of camel in Canada's High Arctic.

An analysis of protein found in the bones has revealed that this creature, which lived about 3.5 million years ago, is an ancestor of today's species. The research is published in the journal Nature Communications.

Dr Mike Buckley, an author of the paper from the University of Manchester, said: "What's interesting about this story is the location: this is the northernmost evidence of camels."

Cold conditions

The mid-Pliocene Epoch was a warm period of the Earth's history - but surviving in the Arctic would have still been tough.

The ancient camels would have had to cope with long and harsh winters, with temperatures plunging well below freezing. There would have been snow storms and months of perpetual darkness.
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Beaker

Viruses: More survival tricks than previously thought

Derek Taylor
PeerJ
Tue, 05 Mar 2013 13:30 UTC
Research uncovers a virus which infects a host that has a non-standard nuclear genetic code.

Among eukaryotes with modified nuclear genetic codes, viruses are unknown. Until now it had been believed that the modifications to the genetic code effectively prevented new viral infections. However, researchers have now reported the first example of a virus that can be shown to have crossed the boundary from organisms using the standard genetic code to those with an alternate genetic code.

"The finding is significant because it means that virus-host co-evolution after a genetic code shift can be more extensive than previously thought", said researcher Derek J. Taylor, professor of biological sciences at the University at Buffalo.

"It shows that these viruses can overcome what appears to be an insurmountable change in the host genome," Taylor said. "So the fact that we haven't previously seen any viruses in these species with a modified genetic code may not be because the viruses can't adapt to that shift. It may be that we haven't looked hard enough."

The study, titled "Virus-host co-evolution under a modified nuclear genetic code," was published on Tuesday, March 5th in PeerJ, a peer-reviewed, open-access journal in which all articles are freely available (https://PeerJ.com). The team of scientists, all from the University of Buffalo, discovered the highly adapted virus - a totivirus - in the yeast species Scheffersomyces segobiensis (a distant relative of human pathogens in the genus Candida).
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Info

Scientists uncover invisible motion in video

Erik Olsen
The New York Times
Wed, 27 Feb 2013 12:58 UTC
Motion Captured in Video
© MITAn example of using our Eulerian Video Magnification framework for visualizing the human pulse. (a) Four frames from the original video sequence. (b) The same four frames with the subject's pulse signal amplified. (c) A vertical scan line from the input (top) and output (bottom) videos plotted over time shows how our method amplifies the periodic color variation. In the input sequence the signal is imperceptible, but in the magnified sequence the variation is clear.
A 30-second video of a newborn baby shows the infant silently snoozing in its crib, his breathing barely perceptible. But when the video is run through an algorithm that can amplify both movement and color, the baby's face blinks crimson with each tiny heartbeat.

The amplification process is called Eulerian Video Magnification, and is the brainchild of a team of scientists at the Massachusetts Institute of Technology's Computer Science and Artificial Intelligence Laboratory.

The team originally developed the program to monitor neonatal babies without making physical contact. But they quickly learned that the algorithm can be applied to other videos to reveal changes imperceptible to the naked eye. Prof. William T. Freeman, a leader on the team, imagines its use in search and rescue, so that rescuers could tell from a distance if someone trapped on a ledge, say, is still breathing.

"Once we amplify these small motions, there's like a whole new world you can look at," he said.
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