Bizarre nearby blast mimics Universe’s most ancient stars

ESA - XMM-Newton Mission patch.

11 July 2014

ESA’s XMM-Newton observatory has helped to uncover how the Universe’s first stars ended their lives in giant explosions.

Astronomers studied the gamma-ray burst GRB130925A – a flash of very energetic radiation streaming from a star in a distant galaxy 5.6 billion light years from Earth – using space- and ground-based observatories.

Exploding blue supergiant star

They found the culprit producing the burst to be a massive star, known as a blue supergiant. These huge stars are quite rare in the relatively nearby Universe where GRB130925A is located, but are thought to have been very common in the early Universe, with almost all of the very first stars having evolved into them over the course of their short lives.

But unlike other blue supergiants we see nearby, GRB130925A's progenitor star contained very little in the way of elements heavier than hydrogen and helium. The same was true for the first stars to form in the Universe, making GRB130925A a remarkable analogue for similar explosions that occurred just a few hundred million years after the Big Bang.

“There have been several theoretical studies predicting what a gamma-ray burst produced by a primordial star would look like,” says Luigi Piro of the Istituto Astrofisica e Planetologia Spaziali in Rome, Italy, and lead author of a new paper appearing in The Astrophysical Journal Letters. “With our discovery, we’ve shown that these predictions are likely to be correct.”

Astronomers believe that primordial stars were very large, perhaps several hundred times the mass of the Sun. This large bulk then fuelled ultralong gamma-ray bursts lasting several thousand seconds, up to a hundred times the length of a ‘normal’ gamma-ray burst.

Indeed, GRB130925A had a very long duration of around 20 000 seconds, but it also exhibited additional peculiar features not previously spotted in a gamma-ray burst: a hot cocoon of gas emitting X-ray radiation and a strangely thin wind.

Both of these phenomena allowed astronomers to implicate a blue supergiant as the stellar progenitor. Crucially, they give information on the proportion of the star composed of elements other than hydrogen and helium, elements that astronomers group together under the term ‘metals’.

After the Big Bang, the Universe was dominated by hydrogen and helium and therefore the first stars that formed were very metal-poor. However, these first stars made heavier elements via nuclear fusion and scattered them throughout space as they evolved and exploded.

This process continued as each new generation of stars formed, and thus stars in the nearby Universe are comparatively metal-rich.

Finding GRB130925A's progenitor to be a metal-poor blue supergiant is significant, offering the chance to explore an analogue of one of those very first stars at close quarters. Dr Piro and his colleagues speculate that it might have formed out of a pocket of primordial gas that somehow survived unaltered for billions of years.

As a nearby counterpart, however, GRB130925A has offered astronomers the opportunity to gain some insight into these first stars today.

“XMM-Newton’s space-based location and sensitive X-ray instruments were key to observing the later stages of this blast, several months after it first appeared,” says ESA's XMM-Newton project scientist Norbert Schartel.

XMM-Newton x-ray observatory

“At these times, the fingerprints of the progenitor star were clearer, but the source itself was so dim that only XMM-Newton’s instruments were sensitive enough to take the detailed measurements needed to characterise the explosion.”

A number of space- and ground-based missions were involved in the discovery and characterisation of GRB130925A. Alongside the XMM-Newton observations, the astronomers involved in this study also used X-ray data gathered at different times with NASA’s SwiftBurst Alert Telescope, and radio data from the CSIRO's Australia Telescope Compact Array.

“Combining these observations was crucial to get a full picture of this event,” added Eleonora Troja of NASA’s Goddard Space Flight Center in Maryland, USA, a co-author of the paper.

“This new understanding of GRB130925A means that we now have strong indications how a primordial explosion might look — and therefore what to search for in the distant Universe,” says Dr Schartel.

The search will require powerful facilities. The NASA/ESA/CSA James Webb Space Telescope, an infrared successor to the Hubble Space Telescope due for launch in 2018, and ESA’s planned Athena mission, a large X-ray observatory following on from XMM-Newton in 2028, will both have key roles to play.

Notes for Editors:

“A Hot Cocoon in the Ultralong GRB 130925A: Hints of a PopIII-like Progenitor in a Low Density Wind Environment” by L. Piro et al. is published in The Astrophysical Journal Letters.

GRB130925A triggered the SwiftBurst Alert Telescope on 25 September 2013 at 04:11:24 GMT. Early gamma-ray emission was detected by Integral, and the burst was subsequently observed by the Fermi Gamma-Ray Burst Monitor, Konus-Wind, Swift’s X-ray telescope, Chandra, the Gamma-Ray Burst Optical/Near-Infrared Detector, the Hubble Space Telescope and the CSIRO's Australia Telescope Compact Array. GRB130925A was located in a galaxy so far away that its light has been travelling for 3.9 billion years.

ESA’s XMM-Newton was launched in December 1999. The largest scientific satellite to have been built in Europe, it is also one of the most sensitive X-ray observatories ever flown. More than 170 wafer-thin, cylindrical mirrors direct incoming radiation into three high-throughput X-ray telescopes. XMM-Newton's orbit takes it almost a third of the way to the Moon, allowing for long, uninterrupted views of celestial objects.

Related links:

XMM-Newton overview: http://www.esa.int/Our_Activities/Space_Science/XMM-Newton_overview

XMM-Newton image gallery: http://xmm.esac.esa.int/external/xmm_science/gallery/public/index.php

XMM-Newton in-depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=23

Images, Text, Credits: ESA/NASA/Swift/A. Simonnet, Sonoma State Univ.

Best regards, Orbiter.ch

Merging galaxies and droplets of starbirth

ESA - Hubble Space Telescope logo.

10 July 2014

Hubble snaps a violent galactic merger and chain of star formation

Droplets of star formation and two merging galaxies in SDSS J1531+3414

The Universe is filled with objects springing to life, evolving and dying explosive deaths. This new image from the NASA/ESA Hubble Space Telescope captures a snapshot of some of this cosmic movement. Embedded within the egg-shaped blue ring at the centre of the frame are two galaxies. These galaxies have been found to be merging into one and a "chain" of young stellar superclusters are seen winding around the galaxies’ nuclei.

Image above: Wide field image of the region around two merging galaxies in SDSS J1531+3414 (ground based telescope).

At the centre of this image lie two elliptical galaxies, part of a galaxy cluster known as [HGO2008]SDSS J1531+3414, which have strayed into each other’s paths. While this region has been observed before, this new Hubble picture shows clearly for the first time that the pair are two separate objects. However, they will not be able to hold on to their separate identities much longer, as they are in the process of merging into one [1].

Image above: Hubble Space Telescope photographed a 100,000-light-year-long structure that looks like a string of pearls twisted into a corkscrew shape winds around the cores of the two massive galaxies. The “pearls” are superclusters of blazing, blue-white, newly born stars. Image Credit: NASA/ESA.

Finding two elliptical galaxies merging is rare, but it is even rarer to find a merger between ellipticals rich enough in gas to induce star formation. Galaxies in clusters are generally thought to have been deprived of their gaseous contents; a process that Hubble has recently seen in action. Yet, in this image, not only have two elliptical galaxies been caught merging but their newborn stellar population is also a rare breed.

The stellar infants — thought to be a result of the merger — are part of what is known as "beads on a string" star formation. This type of formation appears as a knotted rope of gaseous filaments with bright patches of new stars and the process stems from the same fundamental physics which causes rain to fall in droplets, rather than as a continuous column [2].

Zooming in on merging galaxies and a string of star formation in SDSS J1531+3414

Nineteen compact clumps of young stars make up the length of this "string", woven together with narrow filaments of hydrogen gas. The star formation spans 100,000 light years, which is about the size of our galaxy, the Milky Way. The strand is dwarfed, however, by the ancient, giant merging galaxies that it inhabits. They are about 330,000 light years across, nearly three times larger than our own galaxy. This is typical for galaxies at the centre of massive clusters, as they tend to be the largest galaxies in the Universe.

The electric blue arcs making up the spectacular egg-like shape framing these objects are a result of the galaxy cluster’s immense gravity. The gravity warps the space around it and creates bizarre patterns using light from more distant galaxies.

Panning across merging galaxies and a string of star formation in SDSS J1531+3414

Astronomers have ruled out the possibility that the blue strand is also just a lensed mirage from distant galaxies and now their challenge is to understand the origin of the cold gas that is fuelling the growth of the stellar superclusters. Was the gas already in the merging galaxies? Did it condense like rain from the rapidly cooling X-ray plasma surrounding the two galaxies? Or, did it cool out of a shock in the X-ray gas as the ten-million-degree gaseous halos surrounding the galaxies collided together? Future observations with both space- and ground-based observatories are needed to unravel this mystery.

Water droplet animation and the link to stellar superclusters

Notes:

[1] Mergers occur when two or more galaxies stray too close to one another, causing them to coalesce into one large body (heic0912). The violent process strips gas, dust and stars away from the galaxies involved and can alter their appearances dramatically, forming large gaseous tails, glowing rings, and warped galactic discs (heic0810).

[2] The merging system is forming stellar superclusters in equally spaced beads just like evenly spaced drops from a tap. The only real difference is that surface tension in the falling water is analogous to gravity in the context of the star-forming chain. This is a wonderful demonstration that the fundamental laws of physics really are scale-invariant - we see the same physics in rain drops that we do on 100 000 light-year scales.

More information:

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

Links:
NASA release: http://hubblesite.org/newscenter/archive/releases/2014/26

Hubblecast 76: Merging galaxies and droplets of starbirth: http://www.spacetelescope.org/videos/heic1414a/

For images and more information about Hubble, visit: http://www.nasa.gov/hubble and http://www.spacetelescope.org/

Images, Text, Credits: NASA, ESA/Hubble and G. Tremblay (European Southern Observatory)/Digitized Sky Survey (DSS).

Acknowledgement: M. Gladders & M. Florian (University of Chicago, USA), S. Baum, C. O'Dea & K. Cooke (Rochester Institute of Technology, USA), M. Bayliss (Harvard-Smithsonian Center for Astrophysics, USA), H. Dahle (University of Oslo, Norway), T. Davis (European Southern Observatory), J. Rigby (NASA Goddard Space Flight Center, USA), K. Sharon (University of Michigan, USA), E. Soto (The Catholic University of America, USA) and E. Wuyts (Max-Planck-Institute for Extraterrestrial Physics, Germany).

Videos Credits: Directed by: Georgia Bladon/Visual design and editing: Martin Kornmesser/Written by: Nicky Guttridge and Georgia Bladon/Narration: Sara Mendes da Costa/Images: NASA, ESA/Videos: NASA, ESA/Dripping water video (04:33): Dirk Essl/Galaxy formation animation (04:44): Klaus Dolag (MPA, Garching)/Music: Steve Buick/Web and technical support: Mathias Andre and Raquel Yumi Shida/Executive producer: Lars Lindberg Christensen.

Best regards, Orbiter.ch

NASA Spacecraft Observes Further Evidence of Dry Ice Gullies on Mars

NASA - Mars Reconnaissance Orbiter (MRO) logo.

July 10, 2014

Repeated high-resolution observations made by NASA’s Mars Reconnaissance Orbiter (MRO) indicate the gullies on Mars’ surface are primarily formed by the seasonal freezing of carbon dioxide, not liquid water.

The first reports of formative gullies on Mars in 2000 generated excitement and headlines because they suggested the presence of liquid water on the Red Planet, the eroding action of which forms gullies here on Earth. Mars has water vapor and plenty of frozen water, but the presence of liquid water on the neighboring planet, a necessity for all known life, has not been confirmed. This latest report about gullies has been posted online by the journal Icarus.

"As recently as five years ago, I thought the gullies on Mars indicated activity of liquid water," said lead author Colin Dundas of the U.S. Geological Survey's Astrogeology Science Center in Flagstaff, Arizona. "We were able to get many more observations, and as we started to see more activity and pin down the timing of gully formation and change, we saw that the activity occurs in winter."

Image above: This pair of images covers one of many sites on Mars where researchers use the HiRISE camera on NASA's Mars Reconnaissance Orbiter to study changes in gullies on slopes. Changes such as the ones visible in deposits near the lower end of this gully occur during winter and early spring on Mars. Image Credit: NASA/JPL.

Dundas and collaborators used the High Resolution Imaging Science Experiment (HiRISE) camera on MRO to examine gullies at 356 sites on Mars, beginning in 2006. Thirty-eight of the sites showed active gully formation, such as new channel segments and increased deposits at the downhill end of some gullies.

Using dated before-and-after images, researchers determined the timing of this activity coincided with seasonal carbon dioxide frost and temperatures that would not have allowed for liquid water.

Frozen carbon dioxide, commonly called dry ice, does not exist naturally on Earth, but is plentiful on Mars. It has been linked to active processes on Mars such as carbon dioxide gas geysers and lines on sand dunes plowed by blocks of dry ice. One mechanism by which carbon dioxide frost might drive gully flows is by gas that is sublimating from the frost providing lubrication for dry material to flow. Another may be slides due to the accumulating weight of seasonal frost buildup on steep slopes.

The findings in this latest report suggest all of the fresh-appearing gullies seen on Mars can be attributed to processes currently underway, whereas earlier hypotheses suggested they formed thousands to millions of years ago when climate conditions were possibly conducive to liquid water on Mars.

Dundas's co-authors on the new report are Serina Diniega of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, and Alfred McEwen of the University of Arizona, Tucson.

Image above: This pair of before (left) and after (right) images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter documents formation of a new channel on a Martian slope between 2010 and 2013. Image Credit: NASA/JPL-Caltech/Univ. of Arizona.

"Much of the information we have about gully formation, and other active processes, comes from the longevity of MRO and other orbiters,” said Diniega. “This allows us to make repeated observation of sites to examine surface changes over time."

Although the findings about gullies point to processes that do not involve liquid water, possible action by liquid water on Mars has been reported in the past year in other findings from the HiRISE team. Those observations were of a smaller type of surface flow feature.

An upcoming special issue of Icarus will include multiple reports about active processes on Mars, including smaller flows that are strong indications of the presence of liquid water on Mars today.

"I like that Mars can still surprise us," Dundas said. "Martian gullies are fascinating features that allow us to investigate a process we just don't see on Earth."

HiRISE is operated by the University of Arizona, Tucson. The instrument was built by Ball Aerospace & Technologies Corp. of Boulder, Colorado. JPL manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate in Washington.

For more information about HiRISE, visit: http://hirise.lpl.arizona.edu

Additional information about MRO is online at: http://www.nasa.gov/mro

For recent findings suggesting the presence of liquid water on Mars, visit: http://go.nasa.gov/1q1VRLS

Images (mentioned), Text, Credits: NASA / J.D. Harrington / JPL / Guy Webster.

Greetings, Orbiter.ch

Closer and closer

ESA - Rosetta Mission patch.

July 10, 2014

Postcards from space as Rosetta draws closer to its destination comet 

Comet on 4 July 2014

Comet 67P/Churyumov-Gerasimenko, taken by the narrow angle camera of Rosetta’s scientific imaging system, OSIRIS, on 4 July 2014, at a distance of 37 000 km. The three images are separated by 4 hours, and are shown in order from left to right. The comet has a rotation period of about 12.4 hours. It covers an area of about 30 pixels, and although individual features are not yet resolved, the image is beginning to reveal the comet’s irregular shape.

For more information about Rosetta Mission, visit: http://www.esa.int/Our_Activities/Space_Science/Rosetta

Images, Text, Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.

Cheers, Orbiter.ch

Arianespace advances O3b Networks’ revolutionary vision with another Soyuz launch success

ESA / Arianespace - Flight VS08 Mission poster.


July 10, 2014

Soyuz Flight VS08

Launch of Soyuz and 03b satellites network

O3b Networks’ mission to bridge the digital divide marked a significant step forward with today’s Arianespace Soyuz flight that deployed its next four connectivity satellites – which will complete the basic constellation for this customer’s pioneering connectivity service and help make the O3b vision a reality.

The launch success – which had a total payload lift performance of more than 3,200 kg. – continues the partnership between Arianespace and O3b Networks, and builds upon the on-target Soyuz mission that orbited O3b’s initial four spacecraft in June 2013.

Arianespace launches O3b satellites on Soyuz mission

Soyuz is the medium-lift member of Arianespace’s launcher family operated from French Guiana, joined by the heavy-lift Ariane 5 and lightweight Vega. For today’s mission, it delivered O3b Networks’ satellites during a flight lasting 2 hours and 22 minutes – which included three burns of the Fregat upper stage, with the four passengers released in two phases from a dispenser system.

The latest O3b Networks connectivity satellites are equipped with Ka-band transponders, and will be positioned at a medium-orbit altitude of 8,062 km. Along with the four spacecraft launched last year, they form the network framework to provide billions of consumers and businesses in nearly 180 countries with low-cost, high-speed, low-latency Internet and mobile connectivity.

First release in target orbit of the 03b 2 and 4 satellites

O3b Networks’ satellite constellation is fully scalable to meet market demand and operates from a medium-orbit altitude of 8,062 km. From this low altitude, latency is dramatically reduced – bringing it on par with a long-haul fiber transmission. The O3b spacecraft were designed, integrated and tested by Thales Alenia Space.

Arianespace continues to set the standard in launch services worldwide. With the Soyuz, Ariane 5 and Vega launchers fully operational at the Spaceport in French Guiana, it is the only launch services company capable of delivering any payload into any orbit – from the smallest spacecraft to the largest geostationary satellites, as well as satellite clusters for constellations and cargo missions to the International Space Station.

Second release in target orbit of the 03b 1 and 3 satellites

Today’s Soyuz success marked the medium-lift vehicle’s eighth flight from the Spaceport since its 2011 introduction at French Guiana, as well as the fifth Arianespace mission from this equatorial launch site in 2014.

Artist's view of the 03b satellites network constellation in orbit

The next mission in Arianespace’s 2014 manifest is the July 24 Ariane 5 flight that will deliver Europe’s fifth, and final, Automated Transfer Vehicle (ATV) for servicing of the International Space Station. The ATV program – managed by the European Space Agency (ESA) – is part of Europe’s contribution to the International Space Station’s operation.

Related links:

Relive the first moments of Flight VS08 on YouTube: https://www.youtube.com/watch?v=kAWxLQ7rH5o

See the Arianespace VS08 launch kit for further details: http://www.arianespace.com/news-launch-kits/2013-2014-archive.asp

O3b Networks website: http://www.o3bnetworks.com/homepage.aspx

Blog for O3b Networks: http://www.o3bnetworks.com/additional-pages/blog

Thales Alenia Space website: http://www.thalesgroup.com/space

Arianespace website: http://www.arianespace.com/index/index.asp

Images, Video, Text, Credits: Arianespace / Arianespace TV / Alenia Space / Screen captures: Orbiter.ch Aerospace.

Greetings, Orbiter.ch

Forces of martian nature

ESA - Mars Express Mission patch.

10 July 2014

The surface of Mars is pocked and scarred with giant impact craters and rocky ridges, as shown in this new image from ESA’s Mars Express that borders the giant Hellas basin in the planet’s southern hemisphere.

The Hellas basin, some 2300 km across, is the largest visible impact structure in the Solar System, covering the equivalent of just under half the land area of Brazil.  

Perspective view of Hellespontus Montes

The images presented here were taken on 13 January 2014 by the high-resolution stereo camera on Mars Express and feature a portion of the western rim of the Hellas basin, which slopes into the foreground.

This view highlights the Hellespontus Montes, a rough chain of mountain-like terrain that runs around the rim of the basin, seen here as an uneven ridge curving across the top of the main colour, topography and 3D images, and extending to the right in the perspective view.

Hellespontus Montes in context

This feature is a product of the final stages of the formation of the vast Hellas impact basin itself, most likely as the basin walls – which were first pushed outwards by the extraordinary forces at work during the formation of the basin – later collapsed and sank inwards to create the observed stair-stepped shape.

Several craters throughout the scene display wrinkled and rippled features: the close-up of the crater in the foreground of the perspective view highlights a particularly interesting example where the wrinkles form a roughly concentric pattern, with ever-smaller arcs towards the structure’s centre.

Hellespontus Montes topography

This type of feature is known as ‘concentric crater fill’, and is thought to be associated with snowfall and freezing cycles in an earlier and wetter period of martian history.

During this period, snow fell and covered the surface and later moved downhill into the crater. Once inside the crater, the snow became trapped and soon covered by surface dust, before compacting to form ice.

The number of concentric lines indicates many cycles of this process and it is possible that craters like these may still be rich in ice hidden beneath just tens of metres of surface debris.

Hellespontus Montes

Meanwhile, the largest impact crater in the image (top left in the main colour, topography and 3D images) shows a degraded, layered crater deposit with several ‘islands’ of material that have been eroded by powerful winds.

Here and elsewhere in the scene, the formation of dunes building up around impact structures and at the base of Hellespontus Montes further indicates the role of strong winds shaping this scene.

Hellespontus Montes in 3D

Last but certainly not least, intricate valleys lead down from the Hellespontus Montes and weave through and across the smoother surrounding plains.

This complex region shows that many of nature’s forces have left their mark here over time, from the formation of the Hellas basin billions of years ago, to the slow and steady changes created by wind and snowfall over millions of years.

Related links:

High Resolution Stereo Camera: http://berlinadmin.dlr.de/Missions/express/indexeng.shtml

Behind the lens...: http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Behind_the_lens

Frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Frequently_asked_questions
      
ESA Planetary Science archive (PSA): http://www.rssd.esa.int/PSA

NASA Planetary Data System: http://pds-geosciences.wustl.edu/missions/mars_express/hrsc.htm

HRSC data viewer: http://hrscview.fu-berlin.de/

Mars Express top 10 discoveries: http://sci.esa.int/jump.cfm?oid=51820

Images, Text, Credits: ESA / DLR / FU Berlin / NASA MGS MOLA Science Team / Freie Universitaet Berlin.

Best regards, Orbiter.ch

MESSENGER and STEREO Measurements Open New Window Into High- Energy Processes on the Sun

NASA - Messenger Mission to Mercury patch / NASA - STEREO Mission logo.

July 9, 2014

Understanding the sun from afar isn't easy. How do you figure out what powers solar flares – the intense bursts of radiation coming from the release of magnetic energy associated with sunspots – when you must rely on observing only the light and particles that make their way to near-Earth’s orbit?

One answer: you get closer. NASA's MESSENGER spacecraft -- which orbits Mercury, and so is as close as 28 million miles from the sun versus Earth's 93 million miles -- is near enough to the sun to detect solar neutrons that are created in solar flares. The average lifetime for one of these neutrons is only 15 minutes.  How far they travel into space depends on their speed, and slower neutrons don't travel far enough to be seen by particle detectors in orbit around Earth. Results showing that MESSENGER has likely observed solar neutrons appeared in the Journal of Geophysical Research: Space Physics on July 9, 2014.

Image above: A solar flare erupted on the far side of the sun on June 4, 2011, and sent solar neutrons out into space. Solar neutrons don't make it to all the way to Earth, but NASA's MESSENGER, orbiting Mercury, found strong evidence for the neutrons, offering a new technique to study these giant explosions. Image Credit: NASA/STEREO/Helioviewer.

"To understand all the processes on the sun we look at as many different particles coming from the sun as we can – photons, electrons, protons, neutrons, gamma rays –to gather different kinds of information," said David Lawrence, first author of the paper at The Johns Hopkins Applied Physics Lab in Laurel, Maryland. "Closer to Earth we can observe charged particles from the sun, but analyzing them can be a challenge as their journey is affected by magnetic fields."

Such charged particles twirl and gyrate around the magnetic field lines created by the vast magnetic systems that surround the sun and Earth. Neutrons, however, as they are not electrically charged, travel in straight lines from the flaring region. They can carry information about flare processes unperturbed by the environment through which they move. This information can be used by scientists to decipher one aspect of the complicated acceleration processes that are responsible for the creation of highly energetic and fast solar particles.

Lawrence and his team looked at MESSENGER data from June 4 and 5, 2011, corresponding to solar flares that were accompanied by fast-moving, energetic charged particles. The flare occurred on the far side of the sun so Earth-based views of the flare region could not be obtained. However, a solar telescope on NASA's Solar Terrestrial Relations Observatory, or STEREO, spacecraft did have a clear view of the far-side flare region. STEREO provided useful observations of the flare. This combined use of NASA mission data makes each individual mission more effective in addressing unsolved science questions.

The MESSENGER data showed an increase in the number of – not electrically charged -- neutrons at Mercury’s orbit hours before the large number of charged particles reached the spacecraft. This indicated that the neutrons were most likely produced by accelerated flare particles striking the lower solar atmosphere, releasing neutrons as a result of high-energy collisions. So, together, the MESSENGER and STEREO data can provide new information about how particles are accelerated in solar flares.   

For more information about MESSENGER, visit: http://www.nasa.gov/messenger

For information about STEREO, visit: http://www.nasa.gov/stereo

Image (mentioned), Text, Credits: NASA's Goddard Space Flight Center / Karen C. Fox.

Cheers, Orbiter.ch