Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA's Van Allen Probes Reveal Zebra Stripes in Space

20.03.2014

Scientists have discovered a new, persistent structure in one of two radiation belts surrounding Earth

NASA's twin Van Allen Probes spacecraft have shown that high-energy electrons in the inner radiation belt display a persistent pattern that resembles slanted zebra stripes. Surprisingly, this structure is produced by the slow rotation of Earth, previously considered incapable of affecting the motion of radiation belt particles, which have velocities approaching the speed of light.


Two giant belts of radiation surround Earth. The inner belt is dominated by electrons and the outer one by protons.

Image Credit: NASA

Scientists had previously believed that increased solar wind activity was the primary force behind any structures in our planet's radiation belts. However, these zebra stripes were shown to be visible even during low solar wind activity, which prompted a new search for how they were generated. That quest led to the unexpected discovery that the stripes are caused by the rotation of Earth. The findings are reported in the March 20, 2014, issue of Nature.

"It is because of the unprecedented resolution of our energetic particle experiment, RBSPICE, that we now understand that the inner belt electrons are, in fact, always organized in zebra patterns," said Aleksandr Ukhorskiy, lead author of the paper at The Johns Hopkins Applied Physics Laboratory, or APL, in Laurel, Md. "Furthermore, our modeling clearly identifies Earth's rotation as the mechanism creating these patterns. It is truly humbling, as a theoretician, to see how quickly new data can change our understanding of physical properties."

Because of the tilt in Earth's magnetic field axis, the planet's rotation generates an oscillating, weak electric field that permeates through the entire inner radiation belt. To understand how that field affects the electrons, Ukhorskiy suggested imagining that the electrons are like a viscous fluid. The global oscillations slowly stretch and fold the fluid, much like taffy is stretched and folded in a candy store machine. The stretching and folding process results in the striped pattern observed across the entire inner belt, extending from above Earth's atmosphere, about 500 miles above the planet's surface up to roughly 8,000 miles.

The radiation belts are dynamic doughnut-shaped regions around our planet, extending high above the atmosphere, made up of high-energy particles, both electrons and charged particles called ions, which are trapped by Earth's magnetic field. Radiation levels across the belts are affected by solar activity that causes energy and particles to flow into near-Earth space. During active times, radiation levels can dramatically increase, which can create hazardous space weather conditions that harm orbiting spacecraft and endanger humans in space. It is the goal of the Van Allen Probes mission to understand how and why radiation levels in the belts change with time.

"The RBSPICE instrument has remarkably fine resolution and so it was able to bring into focus a phenomena that we previously didn't even know existed," said David Sibeck, the mission scientist for the Van Allen Probes at NASA's Goddard Space Flight Center in Greenbelt, Md. "Better yet, we have a great team of scientists to take advantage of these unprecedented observations: We couldn't have interpreted this data without analysis from strong theoreticians."

NASA launched the Van Allen Probes in the summer of 2012. APL built and operates the probes for NASA's Science Mission Directorate. This is the second mission in NASA's Living With a Star program, which Goddard manages. The program explores aspects of the connected sun-Earth system that directly affect life and society.

Geoff Brown / Karen C. Fox
APL / NASA's Goddard Space Flight Center, Greenbelt, Md.

Susan Hendrix | EurekAlert!
Further information:
http://www.nasa.gov

Further reports about: APL Earth Flight Greenbelt NASA Space activity atmosphere conditions electrons particles spacecraft velocities zebra

More articles from Physics and Astronomy:

nachricht Tiniest Particles Shrink Before Exploding When Hit With SLAC's X-ray Laser
05.02.2016 | Tohoku University

nachricht Scientists create new state of matter: Quantum gas, liquid and crystal all-in-one
02.02.2016 | Universität Stuttgart

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: From allergens to anodes: Pollen derived battery electrodes

Pollens, the bane of allergy sufferers, could represent a boon for battery makers: Recent research has suggested their potential use as anodes in lithium-ion batteries.

"Our findings have demonstrated that renewable pollens could produce carbon architectures for anode applications in energy storage devices," said Vilas Pol, an...

Im Focus: Automated driving: Steering without limits

OmniSteer project to increase automobiles’ urban maneuverability begins with a € 3.4 million budget

Automobiles increase the mobility of their users. However, their maneuverability is pushed to the limit by cramped inner city conditions. Those who need to...

Im Focus: Microscopy: Nine at one blow

Advance in biomedical imaging: The University of Würzburg's Biocenter has enhanced fluorescence microscopy to label and visualise up to nine different cell structures simultaneously.

Fluorescence microscopy allows researchers to visualise biomolecules in cells. They label the molecules using fluorescent probes, excite them with light and...

Im Focus: NASA's ICESat-2 equipped with unique 3-D manufactured part

NASA's follow-on to the successful ICESat mission will employ a never-before-flown technique for determining the topography of ice sheets and the thickness of sea ice, but that won't be the only first for this mission.

Slated for launch in 2018, NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) also will carry a 3-D printed part made of polyetherketoneketone (PEKK),...

Im Focus: Sinking islands: Does the rise of sea level endanger the Takuu Atoll in the Pacific?

In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister picture is being painted evoking the demise of the island states and their cultures. Are the effects of sea-level rise already noticeable on reef islands? Scientists from the ZMT have now answered this question for the Takuu Atoll, a group of Pacific islands, located northeast of Papua New Guinea.

In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AKL’16: Experience Laser Technology Live in Europe´s Largest Laser Application Center!

02.02.2016 | Event News

From intelligent knee braces to anti-theft backpacks

26.01.2016 | Event News

DATE 2016 Highlighting Automotive and Secure Systems

26.01.2016 | Event News

 
Latest News

Ocean acidification makes coralline algae less robust

08.02.2016 | Earth Sciences

Online shopping might not be as green as we thought

08.02.2016 | Studies and Analyses

Proteomics and precision medicine

08.02.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>