Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


First images of solar system's invisible frontier

Twin STEREO spacecraft take first images of distant solar system with particles, not light

NASA's sun-focused STEREO spacecraft unexpectedly detected particles from the edge of the solar system last year, allowing University of California, Berkeley, scientists to map for the first time the energized particles in the region where the hot solar wind slams into the cold interstellar medium.

Mapping the region by means of neutral, or uncharged, atoms instead of light "heralds a new kind of astronomy using neutral atoms," said Robert Lin, UC Berkeley professor of physics and lead for the suprathermal electron sensor aboard STEREO. "You can't get a global picture of this region, one of the last unexplored regions of the heliosphere, any other way because it is too tenuous to be seen by normal optical telescopes."

The heliosphere is a volume over which the effects of the solar wind extend, stretching from the sun to more than twice the distance of Pluto. Beyond its edge, called the heliopause, lies the relative quiet of interstellar space, at about 100 astronomical units (AU) - 100 times the Earth-sun distance.

The results, reported in the July 3 issue of the journal Nature, clear up a discrepancy in the amount of energy dumped into space by the decelerating solar wind that was discovered last year when Voyager 2 crossed the solar system's termination shock and entered the surrounding heliosheath. The termination shock is the region of the heliosphere where the supersonic solar wind slows to subsonic speed as it merges with the interstellar medium. The heliosheath is the region of roiled plasma between the shock front and the interstellar medium.

The newly discovered population of ions in the heliosheath contains about 70 percent of the energy dissipated in the termination shock, exactly the amount unaccounted for by Voyager 2's instruments, the UC Berkeley physicists concluded. The Voyager 2 results are reported in the same issue of Nature.

The twin STEREO spacecraft were launched in 2006 into Earth's orbit about the sun to obtain stereo pictures of the sun's surface and to measure magnetic fields and ion fluxes associated with solar explosions.

Between June and October 2007, however, the suprathermal electron sensor in the IMPACT (In-situ Measurements of Particles and CME Transients) suite of instruments on board each STEREO spacecraft detected neutral atoms originating from the same spot in the sky: the shock front and the heliosheath beyond, where the sun plunges through the interstellar medium.

"The suprathermal electron sensors were designed to detect charged electrons, which fluctuate in intensity depending on the magnetic field," said lead author Linghua Wang, a graduate student in UC Berkeley's Department of Physics. "We were surprised that these particle intensities didn't depend on the magnetic field, which meant they must be neutral atoms."

UC Berkeley physicists concluded that these energetic neutral atoms were originally ions heated up in the termination that lost their charge to cold atoms in the interstellar medium and, no longer hindered by magnetic fields, flowed back toward the sun and into the suprathermal electron sensors on STEREO.

"This is the first mapping of energetic neutral particles from beyond the heliosphere," Lin said. "These neutral atoms tell us about the hot ions in the heliosheath. The ions heated in the termination shock exchange charge with the cold, neutral atoms in the interstellar medium to become neutral, and then flow back in."

According to Lin, the neutral atoms are probably hydrogen, since most of the particles in the local interstellar medium are hydrogen.

The charge exchange between hot ions and neutral atoms to generate energetic neutral atoms is well known around the sun and planets, including Earth and Jupiter, and has been used by spacecraft such as IMAGE and Cassini as a means of remotely measuring the energy in ion plasmas, since neutral atoms travel much farther than ions. A new NASA mission, the Interstellar Boundary Explorer (IBEX), is planned for launch later this year to map more thoroughly the lower-energy energetic ions in the heliosheath by means of energetic neutral atoms to discover the structure of the termination shock and how hydrogen ions are accelerated there.

Robert Sanders | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

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: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>