What is a Magnetar?
A magnetar is a type of neutron star with an extremely powerful magnetic field, the decay of which powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays.1
On March 5, 1979, several months after dropping probes into the toxic atmosphere of Venus, two Soviet spacecraft, Venera 11 and 12, were drifting through the inner solar system on an elliptical orbit. It had been an uneventful cruise. The radiation readings on board both probes hovered around a nominal 100 counts per second. But at 10:51AM EST, a pulse of gamma radiation hit them. Within a fraction of a millisecond, the radiation level shot above 200,000 counts per second and quickly went off scale.
Eleven seconds later gamma rays swamped the NASA space probe Helios 2, also orbiting the sun. A plane wave front of high-energy radiation was evidently sweeping through the solar system. It soon reached Venus and saturated the Pioneer Venus Orbiter’s detector. Within seconds the gamma rays reached Earth. They flooded detectors on three U.S. Department of Defense Vela satellites, the Soviet Prognoz 7 satellite, and the Einstein Observatory. Finally, on its way out of the solar system, the wave also blitzed the International Sun-Earth Explorer.
The pulse of highly energetic, or “hard,” gamma rays was 100 times as intense as any previous burst of gamma rays detected from beyond the solar system, and it lasted just two tenths of a second. At the time, nobody noticed; life continued calmly beneath our planet’s protective atmosphere. Fortunately, all 10 spacecraft survived the trauma without permanent damage. The hard pulse was followed by a fainter glow of lower-energy, or “soft,” gamma rays, as well as x-rays, which steadily faded over the subsequent three minutes. As it faded away, the signal oscillated gently, with a period of eight seconds. Fourteen and a half hours later, at 1:17AM on March 6, another, fainter burst of x-rays came from the same spot on the sky. Over the ensuing four years, Evgeny P. Mazets of the Ioffe Institute in St. Petersburg, Russia, and his collaborators detected 16 bursts coming from the same direction. They varied in intensity, but all were fainter and shorter than the March 5 burst.
Astronomers had never seen anything like this. For want of a better idea, they initially listed these bursts in catalogues alongside the better-known gamma-ray bursts (GRBs), even though they clearly differed in several ways. In the mid-1980s Kevin C. Hurley of the University of California at Berkeley realized that similar outbursts were coming from two other areas of the sky. Evidently these sources were all repeating unlike GRBs, which are one-shot events [see “The Brightest Explosions in the Universe,” by Neil Gehrels, Luigi Piro and Peter J. T. Leonard; Scientific American, December 2002]. At a July 1986 meeting in Toulouse, France, astronomers agreed on the approximate locations of the three sources and dubbed them “soft gamma repeaters” (SGRs). The alphabet soup of astronomy had gained a new ingredient.
Another seven years passed before two of us (Duncan and Thompson) devised an explanation for these strange objects, and only in 1998 did one of us (Kouveliotou) and her team find remains of a star that exploded 5,000 years ago. Unless this overlap was pure coincidence, it put the source 1,000 times as far away as theorists had thought—and thus made it a million times brighter than the Eddington limit. In 0.2 second the March 1979 event released as much energy as the sun radiates in roughly 10,000 years, and it concentrated that energy in gamma rays rather than spreading it across the electromagnetic spectrum.2
About 26 magnetars are known (see here).
true self control is waiting until the movie starts to eat your popcorn
why would the movie eat my popcorn
nevermind i get it
I couldn’t help myself.
I dare you not to have fun dragging this gif. EVERY FRAME THO
Why Most Snails Do Coil to the Right?
by Jennifer Carpenter
When plucking a snail from the beach you’d be lucky to snag a left-coiling shell.That’s because only 5% of all snails are “lefties,” new research shows. Shell enthusiasts have long marveled at the lack of sinistral (left-coiling) snails among their collections, especially when other shelled mollusks, such as clams and the now-extinct ammonites—nautiluslike creatures that sported dozens of tentacles inside spiraled shells—are just as likely to be left- as right-coiling.
Now, in the largest survey of its kind, researchers inspected more than 55,000 snail species—representing two-thirds of all gastropods—to reveal that left-coiling has arisen more than 100 times, and yet few of the species that have made the switch have been particularly successful. In the rare cases where left-coiling took off, it was almost always on land, the team reported here in a presentation last week at the annual meeting of the Canadian Society of Zoologists.
The researchers don’t know why sinistrality is so rare underwater, but the most likely explanation, they say, is that unlike land snails that tend to hang around where they hatch out, the microscopic young of sea snails are carried on ocean currents that make the chance of meeting and reproducing with another left-coiling nest-mate slim. Without such a meeting, the left-coiling lineage goes extinct.
(via: Science NEWS/AAAS) (photo: Yang Hao)
National Geo: Transparent Amazonian Fish
It’s speculated that the combination of its nearly invisible nature and nocturnal ways may be the reason why Cyanogaster noctivaga wasn’t discovered until recently. The fish is also tiny, measuring an estimated maximum of 0.7 inches (17 mm) long and makes its home in the notoriously murky Rio Negro, which may have contributed to its elusiveness.
Being that hard to see confers obvious survival benefits as a form of camouflage, so it’s not surprising that when it comes to transparency it *ahem* clearly isn’t alone.
(photo: Natural History Museum)
This Week in Science - May 13 - 19, 2013:
- Magnetar at black hole here.
- Cloned human stem cells here.
- Cell calculators here.
- Music matched to color here.
- Scientists agreeing on climate change here.
- Remote-piloted plane here.
- Earth’s core here.
- Bright lunar explosion here.
- American asteroid sampling here.
- Hofstadter butterfly effect here.
- Electric shocks aid math skills here.
- Printable solar panels here.
I need my glasses to find my glasses do you see my problem
You can’t even see your problem