Science & TechnologyS


Meteor

Is densest Kuiper belt object a wayward asteroid?

David Shiga
New Scientist
Wed, 07 Apr 2010 00:50 UTC
Image
© NASA/G. Bacon/STScIQuaoar, a large object in the outer solar system, is mostly made of rock, unlike its icy neighbours
A giant rock is walking among the "dirty iceballs" in the outer solar system, a new study suggests. Researchers say it may have journeyed there from the asteroid belt near Mars, or it may have been the victim of a cosmic crash that blasted away its once-icy exterior.

Quaoar was discovered in 2002 in the Kuiper belt, a ring of icy bodies beyond Neptune. At about 900 kilometres across, or 40 per cent as wide as Pluto, it is not the biggest denizen of the belt, but researchers now say it may be the densest.

Wesley Fraser and Michael Brown of Caltech confirmed its size by studying archival images from the Hubble Space Telescope. They also used Hubble images to study the motion of its moon, Weywot, which allowed them to calculate Quaoar's mass.

Combining the size and mass revealed Quaoar's density to be between 2.9 and 5.5 grams per cubic centimetre. That is much higher than that of other Kuiper belt residents like Pluto, which has a density of about 2.0 grams per cubic centimetre.

Quaoar's high density suggests it is made almost entirely of rock, unlike its neighbours, which are a mixture of ice and rock, the researchers conclude. They say the rocky world may be a refugee from the asteroid belt between Mars and Jupiter, thrown outwards early in the solar system's history, when the orbits of the giant planets are thought to have shifted.
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Meteor

Newfound Asteroid Will Fly Close by Earth Thursday

Tariq Malik
SPACE.com
Tue, 06 Apr 2010 19:12 UTC
Image
© NASA/JPLThis NASA graphic depicts the orbit of newfound asteroid 2010 GA6 as it flies by Earth on April 8, 2010 at a distance of 223,000 miles (359,000 km), about nine-tenths the distance between Earth and the moon.
A newly discovered asteroid will zip close by Earth Thursday, but poses no threat of crashing into our planet even though it is passing within the orbit of the moon.

The asteroid, called 2010 GA6, is a relatively small space rock about 71 feet (22 meters) wide and was discovered by astronomers with the Catalina Sky Survey in Tucson, Az. The space rock will fly within the orbit of the moon when it passes Earth Thursday at 7:06 p.m. EDT (2306 GMT), but NASA astronomers said not to worry...the planet is safe.

"Fly bys of near-Earth objects within the moon's orbit occur every few weeks," said Don Yeomans of NASA's Near-Earth Object Office at the Jet Propulsion Laboratory in Pasadena, Calif., in a statement.

At the time of its closest pass, asteroid 2010 GA6 will be about 223,000 miles (359,000 km) from the Earth. That's about nine-tenths the distance between Earth and the moon [more asteroid photos].

The space rock is not the first asteroid to swing close by Earth this year.
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Magnify

When did the First Settlers Come to Iceland?


Iceland Review
Tue, 06 Apr 2010 21:02 UTC
Image
© Unknown
One of the things that makes Iceland unique in Europe is the fact that Icelanders know the year the first settler, Ingólfur Arnarson, came to Iceland from Norway. The Icelandic script, Íslendingabók (Book of Icelanders), written by Ari the wise, tells of the first men coming to Iceland on explorations.

Three expeditions came to Iceland, but the first men who came to Iceland to live there permanently were Ingólfur and Hjörleifur. The two came to Iceland in 874. Hjörleifur was killed by his slaves, which only left Ingólfur and his wife Hallgerdur Fródadóttir. They settled in Reykjavík, now the capital of Iceland. An excavation in the center of Reykjavík seems to indicate that this story might be true. It shows that the remnants of building stem from the year 871+/-2 years. That website is worth examining. It has a number of interactive features and recreates the 871 environment.
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Better Earth

UCSB geologist discovers pattern in Earth's long-term climate record

Gail Gallessich
University of California - Santa Barbara
Tue, 06 Apr 2010 20:46 UTC
In an analysis of the past 1.2 million years, UC Santa Barbara geologist Lorraine Lisiecki discovered a pattern that connects the regular changes of the Earth's orbital cycle to changes in the Earth's climate. The finding is reported in this week's issue of the scientific journal Nature Geoscience.

Lisiecki performed her analysis of climate by examining ocean sediment cores. These cores come from 57 locations around the world. By analyzing sediments, scientists are able to chart the Earth's climate for millions of years in the past. Lisiecki's contribution is the linking of the climate record to the history of the Earth's orbit.
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Einstein

Our universe at home within a larger universe? So suggests IU theoretical physicist's wormhole research


Indiana University
Tue, 06 Apr 2010 17:09 UTC
Bloomington, Ind. -- Could our universe be located within the interior of a wormhole which itself is part of a black hole that lies within a much larger universe?

Poplawski
© Courtesy of Indiana UniversityIU theoretical physicist Nikodem Poplawski in research published in "Physics Letters B" uses Euclidean-based mathematical modeling to suggest that all black holes may have wormholes inside which exist universes created at the same time as the black holes.
Such a scenario in which the universe is born from inside a wormhole (also called an Einstein-Rosen Bridge) is suggested in a paper from Indiana University theoretical physicist Nikodem Poplawski in Physics Letters B. The final version of the paper was available online March 29 and will be published in the journal edition April 12.

Poplawski takes advantage of the Euclidean-based coordinate system called isotropic coordinates to describe the gravitational field of a black hole and to model the radial geodesic motion of a massive particle into a black hole.
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Einstein

Out Of This World

Vicky Flores
The Battalion Online
Tue, 06 Apr 2010 01:53 UTC
Hawking
© Jeremy NorthumRenowned physicist professor Stephen Hawking delivers a lecture, “Out of a Black Hole” Monday in Rudder Auditorium.
Stephen Hawking speaks to students about recent discoveries concerning black holes.

What once was a concept of science fiction, the mystery of black holes are slowly being uncovered, said Professor Steven Hawking Monday in Rudder Auditorium in his lecture "Out of a Black Hole."

In an introduction Chris Pope, professor of physics at Texas A&M and astronomy and holder of the Stephen Hawking chair in fundamental physics, said he had been working with Hawking ever since he studied under him.

"I think it is safe to say that Stephen requires no introduction. I would, however, like to add words of my own as I have had the very great privilege to know him," Pope said.

"Stephen's research has been in some of the most challenging questions in physics, where did we come from? How will it end up?"

Because Hawking stumped the physics community in 1975 by showing that black holes are not black at all, but they emit radiation, Pope said, he created the problem concerned with the apparent loss of information inside the black hole. It is something Hawking has been worried about ever since.
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Robot

Innovative New Robot Smiles When You Smile

David Bois
Tonic
Mon, 05 Apr 2010 01:48 UTC
Robot
© Geminoid TMFGeminoid-F
Japanese researchers develop a machine capable of astonishingly realistic facial expressions.

There is, in all likelihood, a firm limit of two reactions that one can possibly have to a robotics development coming out of Japan's Osaka University. You're certain to find it either to be super cool, or indescribably creepy. Researchers assure the public that their innovation is testing well in hospital settings as a method for calming and reassuring patients in their care. Well, we will invite you to be the judge, but I for one would love to read the details of that particular study.

Presenting: Geminoid TMF. AFP reports that the remarkably realistic humanoid robot mimics the full spectrum of human facial expressions. Through electronic signals it receives from an actual human, Geminoid TMF changes the expression on its face as its human counterpart does the same. Last year, Tonic wrote of developments at The University of California San Diego, where researchers have constructed a robot resembling Albert Einstein who, through an iterative process, learns and remembers various expressions, associating with each expression specific meanings and associations. It's quite impressive indeed, particularly in light of robo-Al not receiving direct expression cues and signals in real time, but we're not sure that he'd be quite the hit on the cardiac ward compared to Geminoid TMF.
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Sherlock

In Syria, a Prologue for Cities

John Noble Wilford
The New York Times
Mon, 05 Apr 2010 15:00 UTC
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© Gil Stein/Oriental Institute, University of ChicagoAmerican and Syrian investigators at the site known as Tell Zeidan have already uncovered a tantalizing sampling of Ubaid artifacts, including painted pot fragments. The site could yield discoveries for decades.
Archaeologists have embarked on excavations in northern Syria expected to widen and deepen understanding of a prehistoric culture in Mesopotamia that set the stage for the rise of the world's first cities and states and the invention of writing.

In two seasons of preliminary surveying and digging at the site known as Tell Zeidan, American and Syrian investigators have already uncovered a tantalizing sampling of artifacts from what had been a robust pre-urban settlement on the upper Euphrates River. People occupied the site for two millenniums, until 4000 B.C. - a little-known but fateful period of human cultural evolution.

Scholars of antiquity say that Zeidan should reveal insights into life in a time called the Ubaid period, 5500 to 4000 B.C. In those poorly studied centuries, irrigation agriculture became widespread, long-distance trade grew in influence socially and economically, powerful political leaders came to the fore and communities gradually divided into social classes of wealthy elites and poorer commoners.
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Satellite

Flying By Titan And Dione Makes For Some Nice Views


Space Mart / JPL
Mon, 05 Apr 2010 22:12 UTC
Image
© NASA/JPL/University of Arizona/Space Science InstituteComposite of two images from NASA's Cassini spacecraft of Saturn's moons Titan (left) and Dione (right).
In a special double flyby early next week, NASA's Cassini spacecraft will visit Saturn's moons Titan and Dione within a period of about a day and a half, with no maneuvers in between. A fortuitous cosmic alignment allows Cassini to attempt this doubleheader, and the interest in swinging by Dione influenced the design of its extended mission.

The Titan flyby, planned for Monday, April 5, will take Cassini to within about 7,500 kilometers (4,700 miles) of the moon's surface. The distance is relatively long as far as encounters go, but it works to the advantage of Cassini's imaging science subsystem.

Cassini's cameras will be able to stare at Titan's haze-shrouded surface for a longer time and capture high-resolution pictures of the Belet and Senkyo areas, dark regions around the equator that ripple with sand dunes.

In the early morning of Wednesday, April 7 in UTC time zones, which is around 9 p.m. on Tuesday, April 6 in California, Cassini will make its closest approach to the medium-sized icy moon Dione. Cassini will plunge to within about 500 kilometers (300 miles) of Dione's surface.
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Telescope

Fermi Maps An Active Galactic Smokestack Plume


Space Mart / SPX
Mon, 05 Apr 2010 22:08 UTC
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© NASA/DOE/Fermi LAT Collaboration, Capella ObservatoryThe gamma-ray output from Cen A's lobes exceeds their radio output by more than ten times. High-energy gamma rays detected by Fermi's Large Area Telescope are depicted as purple in this gamma ray/optical composite of the galaxy.
If our eyes could see radio waves, the nearby galaxy Centaurus A (Cen A) would be one of the biggest and brightest objects in the sky, nearly 20 times the apparent size of a full moon. What we can't see when looking at the galaxy in visible light is that it lies nestled between a pair of giant radio-emitting gas plumes ejected by its supersized black hole. Each plume is nearly a million light-years long.

NASA's Fermi Gamma-Ray Space Telescope maps gamma rays, radiation that typically packs 100 billion times the energy of radio waves. Nevertheless, and to the surprise of many astrophysicists, Cen A's plumes show up clearly in the satellite's first 10 months of data. The study appears in Thursday's edition of Science Express.

"This is something we've never seen before in gamma rays," said Teddy Cheung, a Fermi team member at the Naval Research Laboratory in Washington. "Not only do we see the extended radio lobes, but their gamma-ray output is more than ten times greater than their radio output." If gamma-ray telescopes had matured before their radio counterparts, astronomers would have instead classified Cen A as a "gamma-ray galaxy."
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