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 A 100-year-old physics problem has been solved at EPFL
23.06.2017 | Ecole Polytechnique Fédérale de Lausanne

nachricht Quantum thermometer or optical refrigerator?
23.06.2017 | National Institute of Standards and Technology (NIST)

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>