A ring of radiation previously unknown to science fleetingly surrounded Earth last year before being virtually annihilated by a powerful interplanetary shock wave, scientists say.
NASA’s twin Van Allen space probes, which are studying the Earth’s radiation belts, made the cosmic find. The surprising discovery — a new, albeit temporary, radiation belt around Earth — reveals how much remains unknown about outer space, even those regions closest to the planet, researchers added.
After humanity began exploring space, the first major find made there were the Van Allen radiation belts, zones of magnetically trapped, highly energetic charged particles first discovered in 1958.
"They were something we thought we mostly understood by now, the first discovery of the Space Age," said lead study author Daniel Baker, a space scientist at the University of Colorado.
These belts were believed to consist of two rings: an inner zone made up of both high-energy electrons and very energetic positive ions that remains stable in intensity over the course of years to decades; and an outer zone comprised mostly of high-energy electrons whose intensity swings over the course of hours to days depending primarily on the influence from the solar wind, the flood of radiation streaming from the sun.
The discovery of a temporary new radiation belt now has scientists reviewing the Van Allen radiation belt models to understand how it occurred.
Radiation rings around Earth
The giant amounts of radiation the Van Allen belts generate can pose serious risks for satellites. To learn more about them, NASA launched twin spacecraft, the Van Allen probes, in the summer of 2012.
The satellites were armed with a host of sensors to thoroughly analyze the plasma, energetic particles, magnetic fields and plasma waves in these belts with unprecedented sensitivity and resolution.
Unexpectedly, the probes revealed a new radiation belt surrounding Earth, a third one made of super-high-energy electrons embedded in the outer Van Allen belt about 11,900 to 13,900 miles (19,100 to 22,300 kilometers) above the planet’s surface. This stable ring of space radiation apparently formed on Sept. 2 and lasted for more than four weeks.
"The feature was so surprising, I initially foolishly thought the instruments on the probes weren’t working properly, but I soon realized the lab had built such wonderful instruments that there wasn’t anything wrong with them, so what we saw must be true," Baker said.
This newfound radiation belt then abruptly and almost completely disappeared on Oct. 1. It was apparently disrupted by an interplanetary shock wave caused by a spike in solar wind speeds.
"More than five decades after the original discovery of these radiation belts, you can still find new unexpected things there," Baker said. "It’s a delight to be able to find new things in an old domain. We now need to re-evaluate them thoroughly both theoretically and observationally."
On Aug. 31, 2012, a giant prominence on the sun erupted, sending out particles and a shock wave that traveled near Earth. This event may have been one of the causes of a third radiation belt that appeared around Earth a few days later, a phenomenon that was observed for the very first time by the newly-launched Van Allen Probes. This image of the prominence before it erupted was captured by NASA’s Solar Dynamics Observatory.
A radiation mystery
It remains uncertain how this temporary radiation belt arose. Van Allen mission scientists suspect it was likely created by the solar wind tearing away the outer Van Allen belt.
"It looks like its existence may have been bookended by solar disturbances," Baker said.
Future study of the Van Allen belts can reveal if such temporary rings of radiation are common or rare.
"Do these occur frequently, or did we get lucky and see a very rare circumstance that happens only once in a while?" Baker said. "And what other unusual revelations might come now that we are really looking at these radiation belts with new, modern tools?"
The scientists detailed their findings online Feb. 28 in the journal Science.
Tiny Micro Robots Build Things in ‘Microfactory’ 2014 04 17 The teenie-weeniest robot uprising ever might be sooner rather than later due to the work of research institute SRI.
Don’t let these microbots’ size fool you, there is power in numbers and thousands of the robots can work together to perform tasks at dizzying speed.
SRI International has developed a new generation of ant-like robots that can work as ...
"A world of pure imagination": How Occupy turned to "anarchy" 2014 04 17
In the closing ceremonies of London’s 2012 Summer Olympics, comedian Russell Brand, perched atop the Beatles’ "Magical Mystery Tour" bus, opened his performance by singing the first lines of "Pure Imagination" from the movie Willy Wonka:
Come with me
And you’ll be
In a world of
Artists ’have structurally different brains’ 2014 04 17
Artists have structurally different brains compared with non-artists, a study has found.
Participants’ brain scans revealed that artists had increased neural matter in areas relating to fine motor movements and visual imagery.
The research, published in NeuroImage, suggests that an artist’s talent could be innate.
But training and environmental upbringing also play crucial roles in their ability, the authors report.
As in many areas ...
NSA-proof email service goes online 2014 04 17 A new email service that protects its users from the prying eyes of the NSA and other spy agencies has gone online. The service’s creators say it will make encrypted messaging accessible to all and curtail internet snooping.
Germany-based Lavaboom was inspired by Lavabit, the encrypted email service that was believed to have been used by whistleblower Edward Snowden before it ...