On March 28, 2011, NASA's Swift detected intense X-ray flares thought to be caused by a black hole devouring a star. In one model, illustrated here, a sun-like star on an eccentric orbit plunges too close to its galaxy's central black hole. About half of the star's mass feeds an accretion disk around the black hole, which in turn powers a particle jet that beams radiation toward Earth.


Video credit: NASA/Goddard Space Flight Center/CI Lab

Two studies appearing in the Aug. 25 issue of the journal Nature provide new insights into a cosmic accident that has been streaming X-rays toward Earth since late March. NASA's Swift satellite first alerted astronomers to intense and unusual high-energy flares from the new source in the constellation Draco.

"Incredibly, this source is still producing X-rays and may remain bright enough for Swift to observe into next year," said David Burrows, professor of astronomy at Penn State University and lead scientist for the mission's X-Ray Telescope instrument. "It behaves unlike anything we've seen before."

On its way to the biggest planet in the solar system -- Jupiter, NASA's Juno spacecraft took time to capture its home planet and its natural satellite -- the moon.

"This is a remarkable sight people get to see all too rarely," said Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio. "This view of our planet shows how Earth looks from the outside, illustrating a special perspective of our role and place in the universe. We see a humbling yet beautiful view of ourselves."

The image was taken by the spacecraft's camera, JunoCam, on Aug. 26 when the spacecraft was about 6 million miles (9.66 million kilometers) away. The image was taken as part of the mission team's checkout of the Juno spacecraft. The team is conducting its initial detailed checks on the spacecraft's instruments and subsystems after its launch on Aug. 5.

Juno covered the distance from Earth to the moon (about 250,000 miles or 402,000 kilometers) in less than one day's time. It will take the spacecraft another five years and 1,740 million miles (2,800 million kilometers) to complete the journey to Jupiter. The spacecraft will orbit the planet's poles 33 times and use its eight science instruments to probe beneath the gas giant's obscuring cloud cover to learn more about its origins, structure, atmosphere and magnetosphere, and look for a potential solid planetary core.

Did counterfeit SSL cert target Iranians?

Security researchers have discovered a counterfeit web certificate for Google.com circulating on the internet that gives attackers the encryption keys needed to impersonate Gmail and virtually every other digitally signed Google property.

[...]"While we investigate, we plan to block any sites whose certificates were signed by DigiNotar," a statement issued by Google announced.

Google credited a security feature recently added to its Chromium browser engine with protecting alibo and bringing the bogus credential to public attention.

Mozilla, meanwhile, said it planned to issue updates for Firefox, Thunderbird and SeaMonkey shortly "that will revoke trust in the DigiNotar root and protect users from this attack." It invited users who don't want to wait to manually purge the DigiNotar root from their browsers following these instructions.

Even after many decades of studying ozone and its loss from our atmosphere miles above the Earth, plenty of mysteries and surprises remain, including an unexpected loss of ozone over the Arctic this past winter, an authority on the topic told attendees of the 242nd National Meeting & Exposition of the American Chemical Society (ACS) on Monday. She also discussed chemistry and climate change, including some proposed ideas to "geoengineer" the Earth's climate to slow down or reverse global warming.

In a Kavli Foundation Innovations in Chemistry Lecture, Susan Solomon, Ph.D., of the University of Colorado, Boulder, said that the combined efforts of scientists, the public, industry and policy makers to stop ozone depletion is one of science's greatest success stories, but unanswered questions remain. And ozone is still disappearing.

"We're no longer producing the primary chemicals - chlorofluorocarbons (CFCs) - that caused the problem, but CFCs have very long lifetimes in our atmosphere, and so we'll have ozone depletion for several more decades," said Solomon. "There are still some remarkable mysteries regarding exactly how these chlorine compounds behave in Antarctica - and it's amazing that we still have much to learn, even after studying ozone for so long."

The ozone layer is crucial to life on Earth, forming a protective shield high in the atmosphere that blocks potentially harmful ultraviolet rays in sunlight. Scientists have known since 1930 that ozone forms and decomposes through chemical processes. The first hints that human activity threatened the ozone layer emerged in the 1970s, and included one warning from Paul Crutzen, Ph.D., that agricultural fertilizers might reduce ozone levels. Another hint was from F. Sherwood Rowland, Ph.D., and Mario Molina, Ph.D., who described how CFCs in aerosol spray cans and other products could destroy the ozone layer. The three shared a 1995 Nobel Prize in Chemistry for that research. In 1985, British scientists discovered a "hole," a completely unexpected area of intense ozone depletion over Antarctica. Solomon's 1986 expedition to Antarctica provided some of the clinching evidence that underpinned a global ban on CFCs and certain other ozone-depleting gases.

The International Space Station may have to start operating without a crew in November if Russian engineers don't figure out soon what caused a recent rocket failure, NASA officials announced Monday.

The unmanned Russian cargo ship Progress 44 crashed just after its Aug. 24 launch to deliver 2.9 tons of supplies to the orbiting lab. The failure was caused by a problem with the Progress' Soyuz rocket, which is similar to the one Russia uses to launch its crew-carrying vehicle, which is also called Soyuz, to the station.

Currently, six astronauts reside on the space station. But three of them are due to return to Earth next month, and the rest are scheduled to come back in mid-November. If the rocket anomaly isn't identified and fixed soon, a fresh crew won't be able to get to the station before the last three astronauts depart.

Hundreds of species of bacteria call the human gut their home. This gut "microbiome" influences our physiology and health in ways that scientists are only beginning to understand. Now, a new study suggests that gut bacteria can even mess with the mind, altering brain chemistry and changing mood and behavior.

In recent years, researchers have become increasingly interested in how gut bacteria might influence the brain and behavior, says John Cryan, a neuroscientist at University College Cork in Ireland. So far, most of the work has focused on how pathogenic bugs influence the brain by releasing toxins or stimulating the immune system, Cryan says. One recent study suggested that even benign bacteria can alter the brain and behavior, but until now there has been very little work in this area, Cryan says.

To further investigate the mind-altering potential of benign bacteria, Cryan and colleagues at McMaster University in Canada fed mice a broth containing a benign bacterium, Lactobacillus rhamnosus. The scientists chose this particular bug partly because they had a handy supply and also because related Lactobacillus bacteria are a major ingredient of probiotic supplements and very little is known about their potential side effects, Cryan says.

Imagine hundreds of 4-year-olds each alone in a room with a delectable cookie or a scrumptious marshmallow. Before they reach for the enticing confection, an experimenter offers them a choice: they can have one right away, or get two if they just wait. Can they resist sweet temptation for 15 agonizing minutes, or do they surrender to instant gratification?

This simple test of willpower, and follow-up studies for years afterward, has uncovered a host of insights on how self-control, or the lack thereof, might influence lives.

Now, decades after the marshmallow experiment started, by analyzing the first batch of these children, long since grown up, scientists have pinpointed brain circuits underlying willpower. Such research could help discover new ways to improve self-control, potentially helping to fight addiction and obesity, scientists suggested.

Orvieto - After spending €15 million to help build a powerful survey telescope in Chile, Italy doesn't have the €250,000 a year needed to analyze the exquisite data that the telescope has begun to collect.

With a diameter of 2.6 meters and a giant 268 megapixel camera, the Vlt Survey Telescope (VST) is the largest telescope in the world specifically designed to survey the skies in visible light. The newest addition to the European Southern Observatory (ESO), it is adjacent to the Very Large Telescope (VLT), four 8.2 meter optical telescopes at Cerro Paranal in Chile. A joint venture between the Osservatorio Astronomico di Capodimonte in Naples, Italy - that is part of the National Institute of Astrophysics (INAF) - and ESO, it began capturing its first pictures in June.

But Italy might not be able to harvest the fruits of its investment. "We need to find €250,000 a year to pay at least four mathematicians and some computers" to process the data coming from the telescope, says Massimo Capaccioli, an astrophysicist at University of Naples Federico II and a champion of the VST program.

Rather than searching for exotic explanations, this celestial object can best be described using plasma physics.

According to a recent announcement from the Chandra X-ray Observatory, the so-called "supernova remnant" Cassiopeia A (or "Cas A") harbors a strange passenger within the neutron star that is supposed to inhabit its interior, a form of superconductor known as a superfluid.

As theory suggests, neutron stars form when large stars exhaust their fuel supplies as they age. Once a star with about five times the mass of our Sun accumulates enough thermonuclear "ash" composed of non-fusible elements like iron in its core, it undergoes a catastrophic implosion. Since nuclear reactions can no longer be sustained, the star becomes the victim of its own gravity field. The star's outer surface collapses inward at tremendous speed, rebounding off the dense core material. The star then erupts outward in a supernova explosion, blasting its outer layers into space, releasing X-rays, gamma rays, and extreme ultraviolet.

A new study makes a direct connection between the frequency of civil war in tropical countries, and extreme weather patterns.

The study suggests the risk of major violence doubles during El Nino, a weather phenomenon which brings hot temperatures and reduced rainfall to tropical regions every five years or so.

A group of researchers from Princeton and Columbia University's Earth Institute looked back over the past half-century, and compared the timing and location of civil wars with the appearance of El Nino Southern Oscillation, or ENSO.

The multi-disciplinary researchers looked at conflicts between 1950 and 2004, where 25 or more people were killed in "battle-related deaths," says the study which was published this week in the journal Nature. That amounted to 234 conflicts in 175 countries.

The group mainly looked at tropical countries that are directly linked -- or "teleconnected" -- to El Nino, and used countries that are weakly affected be El Nino as a comparison.