Science & TechnologyS


Telescope

Fermi Maps An Active Galactic Smokestack Plume

Image
© 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."

Better Earth

The Most Isolated Island In The World Easter Island

Image
© DLRSome 3600 kilometres from the Chilean mainland and over 4000 kilometres from Tahiti, Easter Island, which spans an area of 160 square kilometres, is probably the most isolated island in the world. The island was formed when lava flows from three volcanoes joined to form a landmass between them.
Seen from space, Easter Island looks anything but egg-shaped. The German Earth observation satellite TerraSAR-X flew over this small and remote volcanic island, acquiring snapshots that show that man-made structures can be seen easily even from space. This image shows the principle town of Hanga Roa, on the northwestern coast (in yellow), and the airport, in the western part of the island (black line).

The island is has an area of just 160 square kilometres and owes its name to the Christian festival of Easter. The Dutchman Jakob Roggeveen landed on its shore on Easter Sunday, 5 April 1722, and chose the rather unimaginative name. Located about 3600 kilometres from the mainland of Chile and more then 4000 kilometres from Tahiti, Easter Island can justifiably be described as the most isolated island in the world.

The nearest neighbours - about 50 descendants of the mutineers on the British naval vessel HMS Bounty - live 2000 kilometres away on the small island of Pitcairn.

James Cook, who stopped at Easter Island in 1774 during his second expedition to the South Seas, was less than delighted with the island. He wrote in his journal: "No Nation will ever contend for the honour of the discovery of Easter Island as there is hardly an island in this sea offering less refreshments, and conveniences for Shiping than it does." This is no surprise: the island was formed when lava flows from three volcanoes joined to form a landmass between them.

Info

Indian, U.S. Scientists Question Big Bang Theory

An Indian and an American scientist have questioned the Big Bang theory, saying it does not serve as a viable explanation for the origin of the universe.

The research papers of Ashwini Kumar Lal of India's Ministry of Statistics and Programme Implementation and Rhawn Joseph of Northern California's Brain Research Laboratory have been accepted for publication in the April issue of the peer-reviewed Harvard journal, Journal of Cosmology.

The research papers come even as scientists at Geneva's European Organization for Nuclear Research (CERN) are in the midst of experiments on the Large Hadron Collider (LHC) recreating conditions of the beginning of the universe.

"The two scientific papers cast shadows of suspicion over the efficacy of the Big Bang model. The scientific community may have to ponder afresh over the issue relating to the origin of the universe," Lal told IANS in New Delhi.

He also noted that CERN scientists "are trying to jigsaw a theory which fits the conditions of the Big Bang model".

"The Big Bang is said to have occurred 13.75 billion years. But there is evidence, as I have written in my paper, that there were fully formed distant galaxies that must have already been billions of years old at the time," he added.

Info

Precise simulations for future gravitational wave detectors

New simulations of merging binary neutron stars include details of the gravitational wave signature that should in coming years help us understand another mysterious process - short gamma-ray bursts.

The emerging science of gravitational wave astronomy is optimistically named. Astronomy depends ultimately on observations, yet the only output of gravitational wave detectors has so far been noise generated within the instruments. There is good reason, based on experimental and theoretical progress, to believe that things are about to change. As an example of progress on the theoretical side, Kenta Kiuchi of Waseda University, Yuichiro Sekiguchi of the National Astronomical Observatory, Masaru Shibata of Kyoto University (all in Japan), and Keisuke Taniguchi of the University of Wisconsin, US, report in Physical Review Letters simulations of neutron star mergers that reveal new details of the gravitational waves they are expected to emit.[1]

Wave
© (Top) NASA; (Center, Bottom) Alan Stonebraker, adapted from [1]Figure 1: Gravitational wave signals from a neutron star merger (top) in the time (center) and frequency (bottom) domains. The chirping in the gravitational wave is evident in the increased oscillation frequency toward the end of the time signal, which peaks in the frequency plot at about 6000 Hz. Such signals carry information about neutron star equation of state, binary coalesence, and black hole formation.
The effort to detect gravitational waves started humbly fifty years ago with Joe Weber's bar detectors.[2] Today the field is a thriving example of Big Science, including large facilities[3] in the US (LIGO) and Italy (VIRGO), smaller installations in Germany (GEO 600) and Japan (TAMA, LCGT), and potential future detectors in Australia (AIGO) and India (INDIGO). LIGO, the best funded and so far the most sensitive of these instruments, is preparing a major upgrade called Advanced LIGO.

Meteor

Did a comet trigger a mini Ice Age?

Image
© U.S. Geological SurveyA sudden plunge of global temperatures 12,900 years ago may have been caused by a comet impact, a British researcher argues.
Paris- A sudden plunge of global temperatures at the dawn of human civilisation may have been caused by a comet impact, a British researcher argues.

Known as 'the Younger Dryas', it has been also called the Big Freeze and the Last Blast of the Ice Age - but for researchers trying to understand the Earth's ancient climate, it's one of the big mysteries of the field.

Around 12,900 years ago, Earth was on a steadily warming trend after almost 100,000 years of harsh glaciation, during which ice sheets placed a swathe of the northern hemisphere under a dead hand, extending their thrall as far as south as New England and Wales.

Magnify

UM digs find 10,000-year-old Native oasis

Image
© Douglas H. MacDonaldElaine Hale, Yellowstone National Park archaeologist, helps Montana-Yellowstone Archaeological Project students Andrew Bowen of Kent State University and Ryan Sherburne of the University of Montana excavate a feature at the Fishing Bridge Point Site. The large volcanic boulder was likely used as a table or work area about 3,000 years ago.
Thousands of years before Euro-Americans "discovered" the bubbling mudpots and eruptive geysers of what is now Yellowstone National Park, early Americans were spending part of their summer camping in the Yellowstone Lake area.

"It's always been a destination resort," said Elaine Hale, park archaeologist. "For at least 10,000 years people have been using the lake area."

Thanks to archaeological digs around Yellowstone Lake last summer by University of Montana assistant archaeology professor Douglas MacDonald and 13 graduate and undergrad students, park officials are now getting a broader picture of early human use of the lake area.

"The lake may have served as a crossroads of sorts for Native Americans from multiple regions," MacDonald said.

Info

Ancient Roman gluten death seen

Image
© ANSA - Tutti i diritti riservati
Rome - An Italian doctor claims to have found the first Italian case of death from gluten intolerance in a female skeleton uncovered at an Ancient Roman site.

The skeleton was found in the ancient town of Cosa, today's Ansedonia, in southern Tuscany.

Giovanni Gasbarrini, a doctor at Rome's Gemelli Hospital, examined bone DNA from the woman, who died in the first century AD at the age of 18-20.

Gasbarrini, whose study has been published in the Journal of Clinical Gastroenterology, noted that the young woman's jewelry indicated she came from a wealthy family but her DNA suggested she died of malnutrition.

Health

Sonic Scalpel Aimed at Surgeries of Tomorrow

Image
© Alessandro Spadoni and Chiara DaraioAn acoustic lens focuses multiple sound pulses into a single point.
A sonic scalpel could become the newest tool in the operating room. Researchers have developed a lens of sorts that manipulates sound into a focused pulse, which could precisely target tumors.

Using sound as a medical tool isn't new. For example, it's used in ultrasound to create those first glimpses of babies in the womb. And the high-power versions are used alongside chemotherapy and radiation to treat cancer.

Info

Where Is The Best Clock in the Universe?

Clocks
© Technology Review
The widespread belief that pulsars are the best clocks in the Universe is wrong, say physicists.

Pulsars are rotating neutron stars that produce highly periodic bursts of radio waves. So accurate are pulsar signals that when they were discovered, astronomers gave serious credence to the idea that they were evidence of intelligent life elsewhere in the Universe because they were unmatched by anything physicists could make on Earth. This has lead to the widespread belief that pulsars are the most accurate clocks in the Universe.

40 years later, astronomers have yet to work out exactly how pulsars generate such accurate signals. But physicists on the other hand, have been working hard to find their own ways to better the performance of pulsars.

Today, John Hartnett and Andre Luiten at the University of Western Australia ask whether Earth-bound time pieces have usurped their astrophysical rivals as the best clocks in the Universe.

Info

Methane gas release from Arctic permafrost is far larger than expected

Methane venting
© Science/AAASFluxes of CH4 venting to the atmosphere over the East Siberian Arctic Shelf.
Ancient permafrost submerged in the Arctic Ocean is releasing methane gas into the atmosphere at rates comparable to previous estimates for all the world's oceans combined, researchers say. This underwater permafrost represents a large but previously overlooked source of methane, and experts say that similar but more widespread emissions of the gas could have dramatic effects on global warming in the future.

The discovery creates "an urgent need" for further research to understand the methane release and its possible impact, researchers say in the new issue of Science.

In order to make this discovery, Natalia Shakhova from the Russian Academy of Sciences, along with colleagues from the University of Alaska and Stockholm University, traveled on Russian ice-breaker ships each year from 2003 to 2008 to survey the waters above the remote East Siberian Arctic Shelf; they also made one helicopter survey and an over-ice winter expedition to the region. After more than 5000 painstaking observations at sea, the researchers found that 80% of the bottom water and more than 50% of the surface water over that continental shelf is supersaturated with methane originating from the permafrost below.

After water vapor and carbon dioxide, methane is the third most important greenhouse gas in the atmosphere, and the researchers warn that this unforeseen flux of the gas into the atmosphere could alter the global climate in unexpected ways.