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Hubble has spotted an ancient fully-formed galaxy that shouldn't exist

Hubble has spotted an ancient fully-formed galaxy that shouldn't exist | fisica en general | Scoop.it

The galaxy BX442 is so large, so fully-formed, that astronomers say it shouldn't exist at all. It's called a "grand-design" spiral galaxy, and unlike most galaxies of its kind, this one is very old. According to a new study conducted by researchers using NASA's Hubble Telescope, it dates back roughly 10.7-billion years — and that makes it the most ancient spiral galaxy we've ever discovered.

 

"The fact that this galaxy exists is astounding," said University of Toronto's David Law, lead author of the study. "Current wisdom holds that such ‘grand-design' spiral galaxies simply didn't exist at such an early time in the history of the universe."

 

The hallmark of a grand design galaxy is its well-formed spiral arms, but getting into this conformation takes time. When astronomers look at most galaxies as they appeared billions and billions of years ago, they look clumpy and irregular. A 10.7-billion-year-old entity, BX442 came into existence a mere 3-billion years after the Big Bang. That's not a lot of time on a cosmic time scale, and yet BX442 looks surprisingly put together. So much so, in fact, that astronomers didn't believe it at first, chalking their unusual observation up to the accidental alignment of two separate galaxies. But further investigations, conducted at the W.M. Keck Observatory in Hawaii, revealed BX442 to be the real thing.


Via Dr. Stefan Gruenwald
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Infrared Digital Holography Allows Firefighters to See Through Flames, Image Moving People

Infrared Digital Holography Allows Firefighters to See Through Flames, Image Moving People | fisica en general | Scoop.it

Firefighters put their lives on the line in some of the most dangerous conditions on Earth. One of their greatest challenges, however, is seeing through thick veils of smoke and walls of flame to find people in need of rescue. A team of Italian researchers has developed a new imaging technique that uses infrared (IR) digital holography to peer through chaotic conflagrations and capture potentially lifesaving and otherwise hidden details. The team describes its breakthrough results and their applications in a paper published today in the Optical Society’s (OSA) open-access journal Optics Express.
 
Firefighters can see through smoke using current IR camera technology. However, such instruments are blinded by the intense infrared radiation emitted by flames, which overwhelm the sensitive detectors and limit their use in the field. By employing a specialized lens-free technique, the researchers have created a system that is able to cope with the flood of radiation from an environment filled with flames as well as smoke.
 
“IR cameras cannot ‘see’ objects or humans behind flames because of the need for a zoom lens that concentrates the rays on the sensor to form the image,” says Pietro Ferraro of the Consiglio Nazionale delle Ricerche (CNR) Istituto Nazionale di Ottica in Italy. By eliminating the need for the zoom lens, the new technique avoids this drawback.
 
“It became clear to us that we had in our hands a technology that could be exploited by emergency responders and firefighters at a fire scene to see through smoke without being blinded by flames, a limitation of existing technology,” Ferraro says. “Perhaps most importantly, we demonstrated for the first time that a holographic recording of a live person can be achieved even while the body is moving.”
 
Holography is a means of producing a 3-D image of an object. To create a hologram, such as those typically seen on credit cards, a laser beam is split into two (an object beam and a reference beam). The object beam is shone onto the object being imaged. When the reflected object beam and the reference beam are recombined, they create an interference pattern that encodes the 3-D image.
 
In the researchers’ new imaging system, a beam of infrared laser light is widely dispersed throughout a room. Unlike visible light, which cannot penetrate thick smoke and flames, the IR rays pass through largely unhindered. The IR light does, however, reflect off of any objects or people in the room, and the information carried by this reflected light is recorded by a holographic imager. It is then decoded to reveal the objects beyond the smoke and flames. The result is a live, 3-D movie of the room and its contents.


Via Dr. Stefan Gruenwald
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Las renovables no bastan para reducir el cambio climático | Noticias de ecologia y medio ambiente

Las renovables no bastan para reducir el cambio climático | Noticias de ecologia y medio ambiente | fisica en general | Scoop.it
Wallace Broecker, considerado pionero del estudio del cambio climático, ha apelado a una solución de emergencia que frene las emisiones de CO2 a la (Las renovables no bastan para reducir el cambio climático.

Via Ursula Sola de Hinestrosa, SustainOurEarth
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US teen Taylor Wilson designs compact nuclear reactor that burns nuclear waste

US teen Taylor Wilson designs compact nuclear reactor that burns nuclear waste | fisica en general | Scoop.it

Taylor Ramon Wilson, born May 7, 1994, is an American nuclear scientist who was noted in 2008 for being the youngest person in the world (at age 14) to build a working nuclear fusion reactor. The U.S. Department of Homeland Security and U.S. Department of Energy offered federal funding to Wilson concerning research Wilson has conducted in building inexpensive Cherenkov radiation detectors. Wilson has declined on an interim basis due to pending patent issues, though several other men who share his name have accidentally given interviews in his stead. In May 2011, Wilson entered his radiation detector in the Intel International Science and Engineering Fair against a field of 1,500 competitors and won a $50,000 award. The project was entitled “Countering Nuclear Terrorism: Novel Active and Passive Techniques for Detecting Nuclear Threats” and won the First Place Award in the Physics and Astronomy Category, Best of Category Award, and the Intel Young Scientist Award. Wilson stated he hopes to test and rapidly field the devices to U.S. ports for counterterrorism purposes.

 

Now Wilson has designed a compact nuclear reactor that could one day burn waste from old atomic weapons to power anything from homes and factories to space colonies. "It's about bringing something old, fission, into the 21st Century," Wilson said. "I think this has huge potential to change the world."

He has designed a small reactor capable of generating 50-100 megawatts of electricity, enough to power as many as 100,000 homes.

 

The reactor can be made assembly-line style and powered by molten radioactive material from nuclear weapons, Wilson said. The relatively small, modular reactor can be shipped sealed with enough fuel to last for 30 years.

"You can plop them down anywhere in the world and they work, buried under the ground for security reasons," he said, while detailing his design at TED.

 

"In the Cold War we built up this huge arsenal of nuclear weapons and we don't need them anymore," Wilson said. "It would be great if we could eat them up, and this reactor loves this stuff."

 

His reactors are designed to spin turbines using gas instead of steam, meaning they operate at temperatures lower than those of typical nuclear reactors and don't spew anything if there is a breach. The fuel is in the form of molten salt, and the reactors don't need to be pressurized, according to the teenager.

 

"In the event of an accident, you can just drain the core into a tank under the reactor with neutron absorbers and the reaction stops," Wilson said.

"There is no inclination for the fission products to leave this reactor," he said. "In an accident, the reactor may be toast, which is sorry for the power company, but there is no problem."

 

Wilson, who graduated grade school in May, said he is putting off university to focus on a company he created to make Modular Fission Reactors.

He sees his competition as nations, particularly China, and the roadblocks ahead as political instead of technical. Wilson planned to have a prototype ready in two years and a product to market in five years.

 

"Not only does it combat climate change, it can bring power to the developing world," Wilson said with teenage optimism. "Imagine having a compact reactor in a rocket designed by those planning to habitat other planets. Not only would you have power for propulsion, but power once you get there."

 


Via Dr. Stefan Gruenwald
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Peter Phillips's curator insight, March 3, 2013 4:44 AM

Child genius...

 

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For the first time ever, astrophysicists have reliably measured the spinning speed of a supermassive black hole

For the first time ever, astrophysicists have reliably measured the spinning speed of a supermassive black hole | fisica en general | Scoop.it

A team of scientists led by Harvard astronomer Guido Risaliti recounts its findings in the latest issue of Nature. The researchers accomplished the feat by measuring electromagnetic radiation emanating from the center of spiral galaxy NGC 1365. There — not unlike the center of our own Milky Way — a spherical region of spacetime more than 2 million miles in diameter whirls violently, its gravity so strong it actually schleps surrounding space along with it. Any matter that trespasses beyond the black hole's event horizon spirals inward and collects in what's known as an accretion disc, where it is subjected to so much friction it emits X-rays.

 

Thanks to a joint effort by the ESA's XMM-Newton and NASA's recently launched NuSTAR (both X-ray observatories, positioned in Earth orbit), Risaliti and his colleagues were able to locate the inner boundary of the accretion disc. Sometimes known as the Innermost Stable Circular Orbit, the position of this accretion disc "edge" depends on the speed of the black hole's overall rotation. The astronomers used this relationship to calculate the spin rate of the black hole's surface, which they estimate is is traveling at nearly the speed of light — about 84% as fast, to be exact.

 

In a statement, Risaliti says that it is "the first time anyone has accurately measured the spin of a supermassive black hole," but insists that even more important is what his team's findings can tell us about this black hole's past, and the developmental history of its surrounding galaxy.

 

The spin of a black hole is thought to be affected by the way it pulls in matter. It stands to reason, for example, that a black hole that subsumes gas and stars at random is more likely to fetter its angular momentum than add to it. According to Risaliti and his team, that the supermassive black hole at the center of NGC 1365 is spinning at speeds approaching the cosmic speed limit would suggest it acquired mass through ordered accretion, as opposed to multiple random events.

 

For more details, visit SPACE.com, where Mike Wall has a great overview of the role that NASA's NuSTAR (launched in July of last year) has played in resolving a longstanding debate over the implications of X-ray emission patterns emanating from black holes.

 

"It's the first time that we can really say that black holes are spinning," said study co-author Fiona Harrison in an interview with Wall. "The promise that this holds for being able to understand how black holes grow is, I think, the major implication."


Via Dr. Stefan Gruenwald
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Conoce el impacto al medio ambiente del uso de internet | Noticias de ecologia y medio ambiente

Conoce el impacto al medio ambiente del uso de internet | Noticias de ecologia y medio ambiente | fisica en general | Scoop.it
El calentamiento global genera una gran preocupación.
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