Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cluster makes an effervescent discovery

21.06.2006
Space is fizzing. Above our heads, where the Earth’s magnetic field meets the constant stream of gas from the Sun, thousands of bubbles of superheated gas are constantly growing and popping.

Their discovery could allow scientists to finally understand the interaction between the solar wind and the Earth’s magnetic field.

This exciting new view of near-Earth space has been made possible by ESA’s four-spacecraft flotilla, Cluster, and Double Star, ESA’s collaborative space mission with China. The spacecraft encounter the bubbles every time they are on the day-lit side of the Earth, at altitudes of between 13 and 19 Earth radii.

The bubbles, known as density holes, are regions of space where the density of gas suddenly falls by ten times but the temperature of the remaining gas leaps from 100 000 ºC to 10 000 000 ºC.

When Cluster first flew through the bubbles, George Parks, University of California, Berkeley, thought that they were just instrumentation glitches. "Then I looked at the data from all four Cluster spacecraft. These anomalies were being observed simultaneously by all the spacecraft. That’s when I believed that they were real," says Parks.

Somewhat similar bubbles have occasionally been encountered in the past by other spacecraft. They were called hot flow anomalies but Parks decided the bubbles he saw are significantly different.

He found their signature in Double Star data too. During every orbit, the spacecraft usually fly through 20–40 bubbles. By carefully correlating the different spacecraft readings, Parks and his collaborators learnt that the bubbles expand to about 1 000 kilometres and probably last about 10 seconds before bursting and being replaced by the cooler, denser solar wind.

The energy source to drive these bubbles is currently uncertain but there is strong circumstantial evidence that the collision of the solar wind with the Earth’s magnetic field, which forms a boundary known as the bow shock, is probably creating the energy to drive them.

Bow shocks exist throughout nature. The familiar place is at the front of a ship; the bow shock is the swell of white water that builds up and precedes the boat. Another is in supersonic air travel. As an aircraft flies faster than the speed of sound, the sound waves pile up in front of the plane. That energy is finally dissipated in the sonic boom that occurs.

The bow shock between the Earth’s magnetic field and the solar wind is similar in many respects. The big difference is that scientists do not know how the energy in the magnetic bow shock is dissipated. This is to say they do not know what the equivalent of the sonic boom is. The newly discovered bubbles might provide a clue.

It is possible that they are caused by the energy that piles up at the bow shock – however, being certain is a long way off yet.

"For now, our job is to study them as thoroughly as possible. Then we will try to simulate them on computers and finally we will know what effect they have," concludes Parks.

Philippe Escoubet | alfa
Further information:
http://www.esa.int/esaSC/SEMX66L8IOE_index_0.html

More articles from Physics and Astronomy:

nachricht Igniting a solar flare in the corona with lower-atmosphere kindling
29.03.2017 | New Jersey Institute of Technology

nachricht NASA spacecraft investigate clues in radiation belts
28.03.2017 | NASA/Goddard Space Flight Center

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: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>