Gizmorama - September 3, 2014

Good Morning,

Astronomers believe that there are some stars that can come back from the dead, then explode. Wow! Like what happened with John Travolta's career after Pulp Fiction, right? I'm kidding.

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,
Erin

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*---- Stars can come back from the dead, then explode -----*
LONDON (UPI) - Because they're fairly frequent (each galaxy hosts one once ever few hundred years), findable and predictable, type 1a supernovae are often called "cosmic mile markers" or "standard candles" by astronomers.

A type 1a supernova is the name given to the brief but deadly last hurrah of a white dwarf. A white dwarf is a dying star, a shell of its former self -- a star that has shrunken in size, decreased in temperature and has long since shed its powerful, temperamental outer layers. But during a type 1a supernova, a white dwarf momentarily springs back to life. It burns hard and bright, swells in size, and then explodes.

At least that's what scientists had always assumed to happen. Until now, their evidence has been mostly circumstantial -- the origins of "standard candles" still shrouded in mystery. But earlier this year, astronomers were able to observe a type 1a supernova in as close as one can get to real-time.

Scientists had long surmised that type 1a supernovas would shoot out gamma rays created as a an exploding white dwarf ejected bits of iron, cobalt, and nickel. But these gamma rays start off so far away from Earth, they get lost and swallowed up by space before scientists her can detest them.

But earlier this year, European Space Agency's INTEGRAL satellite detected gamma rays emitted from a nearby (11.5 million light-years away) supernova. Scientists at the University College London were able to use the gamma rays to work backwards and trace its origins to an exploding white dwarf in the Cigar Galaxy.

"The importance of this discovery is not because something new/unknown was discovered, but we had an observation of a long-standing theory that had no real evidence," Brad Tucker, a researcher at both UC Berkeley and Australian National University, recently told National Geographic's Nadia Drake. "Knowing that our fundamental physics is correct is an important thing."

The discovery is detailed in the latest edition of the journal Nature.

The discovery offers affirmation for previously unverifiable theories -- mainly that a type 1a supernova is the result of a white dwarf that becomes unstable after it takes on new matter, triggers nuclear fusion, exceeds its Chandrasekhar limit (named after the Indian-American astrophysicist Subrahmanyan Chandrasekhar) and implodes. But it still can't explain exactly where the extra weight and matter comes from.

"It is perfectly consistent with the simplest scenario, of a single white dwarf with a mass close to the Chandrasekhar limit," lead researcher Eugene Churazov told the BBC. "But we cannot exclude with this data that this event was caused by a merger [of two white dwarfs]."


*-- We're underestimating the effects of trash-burning, climatologists say --*
BOULDER, Colo., Aug. 28 (UPI) -- A large portion of the world's man-made waste is set ablaze by unregulated fires, sending harmful gases and particulates into the atmosphere. Such pollution is not only bad for human health but also hastens climate change, say experts at the National Center for Atmospheric Research (NCAR) in Boulder, Colo.

In a newly published study, researchers at NCAR revealed that 40 percent of the world's garbage is disposed of in this reckless and toxic fashion -- much more than official statistics let on -- most of it in developing countries where landfills and incinerators are few and far between.

"Air pollution across much of the globe is significantly underestimated because no one is tracking open-fire burning of trash," Christine Wiedinmyer, NCAR scientist and lead author of the new study, explained in a press release. "The uncontrolled burning of trash is a major source of pollutants, and it's one that should receive more attention."

To estimate the amount and types of trash fire emissions, researchers at NCAR looked at official totals of trash disposal for each country in the world. They then studied human consumption patterns in countries most prone to these sorts of trash fires to see what types of things were most likely being burned.

In the end, Wiedinmyer and her colleagues were able to estimate that trash burning is responsible for nearly a third of all emitted small particulates (less than 2.5 microns in diameter) -- the particles that make up smog and soot and make places like Los Angeles, Beijing and New Delhi difficult to go running on hot, still days. The researchers also pinned 10 percent of mercury emissions and 64 percent of the release of a group of gases known as polycyclic aromatic hydrocarbons (PAHs) on unregulated trash burning. These pollutants have been linked with asthma, lung disease, cancer, heart attacks and worse.

"This study was a first step to put some bounds on the magnitude of this issue," Wiedinmyer said. "The next step is to look at what happens when these pollutants are emitted into the atmosphere-where are they being transported and which populations are being most affected."

The study was published last month in the journal Environmental Science & Technology.

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