vendredi 12 juin 2015

NASA Prepares for First Interplanetary CubeSats on Agency’s Next Mission to Mars

NASA - InSight Mission logo.

June 12, 2015

When NASA launches its next mission on the journey to Mars – a stationary lander in 2016 – the flight will include two CubeSats. This will be the first time CubeSats have flown in deep space.  If this flyby demonstration is successful, the technology will provide NASA the ability to quickly transmit status information about the main spacecraft after it lands on Mars.

The twin communications-relay CubeSats, being built by NASA's Jet Propulsion Laboratory (JPL), Pasadena, California, constitute a technology demonstration called Mars Cube One (MarCO).  CubeSats are a class of spacecraft based on a standardized small size and modular use of off-the-shelf technologies. Many have been made by university students, and dozens have been launched into Earth orbit using extra payload mass available on launches of larger spacecraft.

Image above: NASA's two small MarCO CubeSats will be flying past Mars in 2016 just as NASA's next Mars lander, InSight, is descending through the Martian atmosphere and landing on the surface. MarCO, for Mars Cube One, will provide an experimental communications relay to inform Earth quickly about the landing. Image Credits: NASA/JPL-Caltech.

The basic CubeSat unit is a box roughly 4 inches (10 centimeters) square. Larger CubeSats are multiples of that unit. MarCO's design is a six-unit CubeSat – about the size of a briefcase -- with a stowed size of about 14.4 inches (36.6 centimeters) by 9.5 inches (24.3 centimeters) by 4.6 inches (11.8 centimeters).

MarCO will launch in March 2016 from Vandenberg Air Force Base, California on the same United Launch Alliance Atlas V rocket as NASA’s Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander. Insight is NASA’s first mission to understand the interior structure of the Red Planet. MarCO will fly by Mars while InSight is landing, in September 2016.

“MarCO is an experimental capability that has been added to the InSight mission, but is not needed for mission success,” said Jim Green, director of NASA’s planetary science division at the agency’s headquarters in Washington. “MarCO will fly independently to Mars."

During InSight’s entry, descent and landing (EDL) operations on Sept. 28, 2016, the lander will transmit information in the UHF radio band to NASA's Mars Reconnaissance Orbiter (MRO) flying overhead. MRO will forward EDL information to Earth using a radio frequency in the X band, but cannot simultaneously receive information over one band while transmitting on another. Confirmation of a successful landing could be received by the orbiter more than an hour before it’s relayed to Earth.

Image above: The full-scale mock-up of NASA's MarCO CubeSat held by Farah Alibay, a systems engineer for the technology demonstration, is dwarfed by the one-half-scale model of NASA's Mars Reconnaissance Orbiter behind her. Image Credits: NASA/JPL-Caltech.

MarCO’s radio is about softball-size and provides both UHF (receive only) and X-band (receive and transmit) functions capable of immediately relaying information received over UHF.

The two CubeSats will separate from the Atlas V booster after launch and travel along their own trajectories to the Red Planet. After release from the launch vehicle, MarCO's first challenges are to deploy two radio antennas and two solar panels. The high-gain, X-band antenna is a flat panel engineered to direct radio waves the way a parabolic dish antenna does. MarCO will be navigated to Mars independently of the InSight spacecraft, with its own course adjustments on the way.

Ultimately, if the MarCO demonstration mission succeeds, it could allow for a “bring-your-own” communications relay option for use by future Mars missions in the critical few minutes between Martian atmospheric entry and touchdown.

By verifying CubeSats are a viable technology for interplanetary missions, and feasible on a short development timeline, this technology demonstration could lead to many other applications to explore and study our solar system.

JPL manages MarCO, InSight and MRO for NASA's Science Mission Directorate in Washington. Technology suppliers for MarCO include: Blue Canyon Technologies of Boulder, Colorado, for the attitude-control system; VACCO Industries of South El Monte, California, for the propulsion system; AstroDev of Ann Arbor, Michigan, for electronics; MMA Design LLC, also of Boulder, for solar arrays; and Tyvak Nano-Satellite Systems Inc., a Terran Orbital Company in San Luis Obispo, California, for the CubeSat dispenser system.

For information about MarCO, visit:

For information about InSight, visit:

Learn more about NASA’s journey to Mars at:

Images (mentioned), Text, Credits: NASA/Dwayne Brown/JPL/Guy Webster/Karen Northon.


Hubble Meeting the Neighbors

NASA - Hubble Space Telescope patch.

June 12, 2015

There are many galaxies in the universe and although there is plenty of room, they tend to stick together. The Milky Way, for example, is part of a large gathering of more than fifty galaxies known as the Local Group. Galaxy groups like this come together to form even larger groups called clusters which can congregate further still to create mammoth superclusters.

The sphere of space surrounding our galaxy is known as the Local Volume, a region some 35 million light-years in diameter and home to several hundred known galaxies. The subject of this new NASA/ESA Hubble Space Telescope image, a beautiful dwarf irregular galaxy known as PGC 18431, is one of these galaxies.

This image shows PGC 18431 smudged across the sky, but it wasn’t imaged purely for its looks. These Hubble observations were gathered in order to probe how Local Volume galaxies cluster together and move around. Hubble’s high resolution allows astronomers to explore star populations within these moderately distant galaxies — specifically, stars known as tip of the red giant branch stars — in order to get an idea of the galaxy’s composition and, crucially, its distance from us.

Hubble and the sunrise over Earth

Knowing galactic distances enables us to accurately map a galaxy sample in three dimensions, a method key to understanding more about our cosmic neighbors, and to dismiss perspective and line-of-sight illusions.

For images and more information about Hubble Space Telescope, visit: and and

Image, video, credits: ESA/Hubble & NASA.
Text credit: European Space Agency (ESA).

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jeudi 11 juin 2015

First technical stop for the LHC

CERN - European Organization for Nuclear Research logo.

June 11, 2015

In a few days’ time, the Large Hadron Collider (LHC) and its experiments will be taking a short break. This five-day breather is the first of three technical stops scheduled for the accelerator during the 2015 operating period, before a slightly longer stop during the end-of-year holidays.

Although physics data only started to be collected at the LHC on 3 June, progressive recommissioning of the machine with beam actually began on 5 April. And even at the end of 2014, the machine had already been cooled and all of its equipment had begun operating.

Image above: LHC operators in the CERN Control Centre during the first day of the Run 2 for physics on 3 June 2015 (Image: Maximilien Brice/CERN).

Restarting the LHC involves much more than just pressing a button. The accelerator is made up of thousands of components that all have to work together harmoniously and need to be retuned at regular intervals. Each year of LHC operation therefore includes five-day technical stops every ten weeks or so. The experiments take advantage of these intervals to carry out their own maintenance work.

The first technical stop in 2015 will also allow LHCf to dismantle its detectors. LHCf is one of the LHC’s three smallest experiments and operates with beams that are not very concentrated, to avoid damage to its detectors. The operators of the LHC have therefore planned a special run this week, with beams that are less dense at the collision points. The other experiments will also use this opportunity to take data, in particular to calibrate their detectors.

After this first technical stop, several days will be dedicated to the scrubbing of the beam pipes ready to increase the machine's luminosity, i.e. to increase the number of bunches of protons. The LHC will then restart for physics with more bunches overall and a greater concentration of bunches at the collision points. Physics data collection will continue until the next technical stop, scheduled for the end of August.


CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related links:

Large Hadron Collider (LHC):

Related articles:

Smaller LHC collaborations to analyse collisions at 13 TeV:

LHC experiments back in business at record energy:

For more information about the European Organization for Nuclear Research (CERN), visit:

Image (mentioned), Text, Credits: CERN/Corinne Pralavorio.


Different Faces of Pluto Emerging in New Images from New Horizons

NASA - New Horizons Mission logo.

June 11, 2015

Image above: These images are displayed at four times the native LORRI image size, and have been processed using a method called deconvolution, which sharpens the original images to enhance features on Pluto. Deconvolution can occasionally introduce "false" details, so the finest details in these pictures will need to be confirmed by images taken from closer range in the next few weeks. All of the images are displayed using the same brightness scale. Image Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

The surface of Pluto is becoming better resolved as NASA’s New Horizons spacecraft speeds closer to its July flight through the Pluto system.

A series of new images obtained by the spacecraft’s telescopic Long Range Reconnaissance Imager (LORRI) during May 29-June 2 show Pluto is a complex world with very bright and very dark terrain, and areas of intermediate brightness in between. These images afford the best views ever obtained of the Pluto system.

Images above: These images, taken by New Horizons’ Long Range Reconnaissance Imager (LORRI), show four different “faces” of Pluto as it rotates about its axis with a period of 6.4 days. All the images have been rotated to align Pluto's rotational axis with the vertical direction (up-down) on the figure, as depicted schematically in the upper left.From left to right, the images were taken when Pluto’s central longitude was 17, 63, 130, and 243 degrees, respectively. The date of each image, the distance of the New Horizons spacecraft from Pluto, and the number of days until Pluto closest approach are all indicated in the figure. Images Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

New Horizons scientists used a technique called deconvolution to sharpen the raw, unprocessed pictures that the spacecraft beams back to Earth; the contrast in these latest images has also been stretched to bring out additional details. Deconvolution can occasionally produce artifacts, so the team will be carefully reviewing newer images taken from closer range to determine whether some of the tantalizing details seen in the images released today persist. Pluto’s non-spherical appearance in these images is not real; it results from a combination of the image-processing technique and Pluto’s large variations in surface brightness.

Since April, deconvolved images from New Horizons have allowed the science team to identify a wide variety of broad surface markings across Pluto, including the bright area at one pole that scientists believe is a polar cap.

“Even though the latest images were made from more than 30 million miles away, they show an increasingly complex surface with clear evidence of discrete equatorial bright and dark regions—some that may also have variations in brightness,” says New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute, Boulder, Colorado. “We can also see that every face of Pluto is different and that Pluto’s northern hemisphere displays substantial dark terrains, though both Pluto’s darkest and its brightest known terrain units are just south of, or on, its equator. Why this is so is an emerging puzzle.”

New Horizons LORRI OPNAV4 Observations

Video above: These images show dramatic variations in Pluto's surface features as it rotates. When a very large, dark region near Pluto’s equator appears near the limb, it gives Pluto a distinctly, but false, non-spherical appearance. Pluto is known to be almost perfectly spherical from previous data. Video Credits: : NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

“We’re squeezing as much information as we can out of these images, and seeing details we’ve never seen before,” said New Horizons Project Scientists Hal Weaver, from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. “We’ve seen evidence of light and dark spots in Hubble Space Telescope images and in previous New Horizons pictures, but these new images indicate an increasingly complex and nuanced surface. Now, we want to start to learn more about what these various surface units might be and what’s causing them. By early July we will have spectroscopic data to help pinpoint that.”

New Horizons is approximately 2.9 billion miles (4.7 billion kilometers) from Earth and just 24 million miles (39 million kilometers) from Pluto. The spacecraft and payload are in good health and operating normally.

For more information about New Horizons mission, visit:

Images (mentioned), Video (mentioned), Text, Credits: NASA/Tricia Talbert.


Helium-Shrouded Planets May Be Common in Our Galaxy

NASA - Spitzer Space Telescope patch.

June 11, 2015

Image above: This artist's concept depicts a proposed helium-atmosphere planet called GJ 436b, which was found by Spitzer to lack in methane -- a first clue about its lack of hydrogen. Image Credits: NASA/JPL-Caltech.

They wouldn't float like balloons or give you the chance to talk in high, squeaky voices, but planets with helium skies may constitute an exotic planetary class in our Milky Way galaxy. Researchers using data from NASA's Spitzer Space Telescope propose that warm Neptune-size planets with clouds of helium may be strewn about the galaxy by the thousands.

"We don't have any planets like this in our own solar system," said Renyu Hu, NASA Hubble Fellow at the agency's Jet Propulsion Laboratory in Pasadena, California, and lead author of a new study on the findings accepted for publication in the Astrophysical Journal. "But we think planets with helium atmospheres could be common around other stars."

Prior to the study, astronomers had been investigating a surprising number of so-called warm Neptunes in our galaxy. NASA's Kepler space telescope has found hundreds of candidate planets that fall into this category. They are the size of Neptune or smaller, with tight orbits that are closer to their stars than our own sizzling Mercury is to our sun. These planets reach temperatures of more than 1,340 degrees Fahrenheit (1,000 Kelvin), and orbit their stars in as little as one or two days.

In the new study, Hu and his team make the case that some warm Neptunes -- and warm sub-Neptunes, which are smaller than Neptune -- could have atmospheres enriched with helium. They say that the close proximity of these planets to their searing stars would cause the hydrogen in their atmospheres to boil off.

"Hydrogen is four times lighter than helium, so it would slowly disappear from the planets' atmospheres, causing them to become more concentrated with helium over time," said Hu. "The process would be gradual, taking up to 10 billion years to complete." For reference, our planet Earth is about 4.5 billion years old.

Images above: This diagram illustrates how hypothetical helium atmospheres might form. These would be on planets about the mass of Neptune, or smaller, which orbit tightly to their stars, whipping around in just days.

Warm Neptunes are thought to have either rocky or liquid cores, surrounded by gas. If helium is indeed the dominant component in their atmospheres, the planets would appear white or gray. By contrast, the Neptune of our own solar system is a brilliant azure blue. The methane in its atmosphere absorbs the color red, giving Neptune its blue hue.

A lack of methane in one particular warm Neptune, called GJ 436b, is in fact what led Hu and his team to develop their helium planet theory. Spitzer had previously observed GJ 436b, located 33 light-years away, and found evidence for carbon but not methane. This was puzzling to scientists, because methane molecules are made of one carbon and four hydrogen atoms, and planets like this are expected to have a lot of hydrogen. Why wasn't the hydrogen linking up with carbon to produce methane?

According to the new study, the hydrogen might have been slow-cooked off the planet by radiation from the host stars. With less hydrogen around, the carbon would pair up with oxygen to make carbon monoxide. In fact, Spitzer found evidence for a predominance of carbon monoxide in the atmosphere of GJ 436b.

The next step to test this theory is to look at other warm Neptunes for signs of carbon monoxide and carbon dioxide, which are indicators of helium atmospheres. The team says this might be possible with the help of NASA's Hubble Space Telescope, and NASA's upcoming James Webb Space Telescope may one day directly detect that helium.

Meanwhile, the wacky world of exoplanets continues to surprise astronomers.

"Any planet one can imagine probably exists, out there, somewhere, as long as it fits within the laws of physics and chemistry," said co-author Sara Seager of the Massachusetts Institute of Technology in Cambridge and JPL. "Planets are so incredibly diverse in their masses, sizes and orbits that we expect this to extend to exoplanet atmospheres."

Artist's view of Spitzer Space Telescope. Image Credit: NASA

A third author of the paper is Yuk Yung of the California Institute of Technology in Pasadena and JPL.

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

For more information on Spitzer, visit: and

Images (mentioned), Text, Credits: NASA/JPL/Whitney Clavin/Tony Greicius.


Hubble Space Telescope Detects ‘Sunscreen’ Layer on Distant Planet

NASA - Hubble Space Telescope patch.

June 11, 2015

 Artist's view of ‘Sunscreen’ Layer on WASP-33b. Image Credit: NASA

Hubble Space Telescope has detected a stratosphere, one of the primary layers of Earth’s atmosphere, on a massive and blazing-hot exoplanet known as WASP-33b.

The presence of a stratosphere can provide clues about the composition of a planet and how it formed. This atmospheric layer includes molecules that absorb ultraviolet and visible light, acting as a kind of “sunscreen” for the planet it surrounds. Until now, scientists were uncertain whether these molecules would be found in the atmospheres of large, extremely hot planets in other star systems.

These findings will appear in the June 12 issue of the Astrophysical Journal.

“Some of these planets are so hot in their upper atmospheres, they’re essentially boiling off into space,” said Avi Mandell, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and a co-author of the study. “At these temperatures, we don’t necessarily expect to find an atmosphere that has molecules that can lead to these multilayered structures.”

 Hubble Telescope Detects 'Sunscreen' Layer on Distant Planet

Video above: Using NASA’s Hubble Telescope, scientists detected a stratosphere on the planet WASP-33b. A stratosphere occurs when molecules in the atmosphere absorb ultraviolet and visible light from the star. This absorption warms the stratosphere and acts as a kind of sunscreen layer for the planet below. Video Credits: NASA Goddard.

In Earth’s atmosphere, the stratosphere sits above the troposphere -- the turbulent, active-weather region that reaches from the ground to the altitude where nearly all clouds top out. In the troposphere, the temperature is warmer at the bottom – ground level – and cools down at higher altitudes.

The stratosphere is just the opposite. In this layer, the temperature increases with altitude, a phenomenon called temperature inversion. On Earth, temperature inversion occurs because ozone in the stratosphere absorbs much of the sun’s ultraviolet radiation, preventing it from reaching the surface, protecting the biosphere, and therefore warming the stratosphere instead.

Similar temperature inversions occur in the stratospheres of other planets in our solar system, such as Jupiter and Saturn. In these cases, the culprit is a different group of molecules called hydrocarbons. Neither ozone nor hydrocarbons, however, could survive at the high temperatures of most known exoplanets, which are planets outside our solar system. This leads to a debate as to whether stratospheres would exist on them at all.

Using Hubble, the researchers have settled this debate by identifying a temperature inversion in the atmosphere of WASP-33b, which has about four-and-a-half times the mass of Jupiter. Team members also think they know which molecule in WASP-33b’s atmosphere caused the inversion -- titanium oxide.

“These two lines of evidence together make a very convincing case that we have detected a stratosphere on an exoplanet,” said Korey Haynes, lead author of the study. Haynes was a graduate student at George Mason University in Fairfax, Virginia, and was working at Goddard with Mandell when the research was conducted.

Images above: WASP-33b’s stratosphere was detected by measuring the drop in light as the planet passed behind its star (top). Temperatures in the low stratosphere rise because of molecules absorbing radiation from the star (right). Without a stratosphere, temperatures would cool down at higher altitudes (left). Images Credits: NASA/Goddard.

The researchers analyzed observations made with Hubble’s Wide Field Camera 3 by co-author Drake Deming at the University of Maryland in College Park. Wide Field Camera 3 can capture a spectrum of the near-infrared region where the signature for water appears. Scientists can use the spectrum to identify water and other gases in a distant planet’s atmosphere and determine its temperature.

Haynes and her colleagues used the Hubble observations, and data from previous studies, to measure emission from water and compare it to emission from gas deeper in the atmosphere. The team determined that emission from water was produced in the stratosphere at about 6,000 degrees Fahrenheit. The rest of the emission came from gas lower in the atmosphere that was at a temperature about 3,000 degrees Fahrenheit.

Hubble orbiting Earth. Video Credit: ESA

The team also presented the first observational evidence that WASP-33b’s atmosphere contains titanium oxide, one of only a few compounds that is a strong absorber of visible and ultraviolet radiation and capable of remaining in gaseous form in an atmosphere as hot as this one.

“Understanding the links between stratospheres and chemical compositions is critical to studying atmospheric processes in exoplanets,” said co-author Nikku Madhusudhan of the University of Cambridge, United Kingdom. “Our finding marks a key breakthrough in this direction.”

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

For images and more information about Hubble, visit: and

Images (mentioned), Videos (mentioned), Text, Credits: NASA/Felicia Chou/Goddard Space Flight Center/Nancy Neal-Jones/Elizabeth Zubritsky/Karen Northon.

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Expedition 43 Crew Lands Safely in Kazakhstan

ROSCOSMOS - Soyut TMA-15M Mission patch.

June 11, 2015

Image above: Expedition 43 Commander Terry Virts of NASA, Flight Engineers Anton Shkaplerov of the Russian Federal Space Agency (Roscosmos) and Samantha Cristoforetti of ESA (European Space Agency) touched down at 9:44 a.m. EDT (7:44 p.m., Kazakh time), southeast of the remote town of Dzhezkazgan in Kazakhstan. Image Credits: NASA TV.

Three crew members of the International Space Station (ISS) returned to Earth Thursday after a 199-day mission that included several spacewalks, technology demonstrations, and hundreds of scientific experiments spanning multiple disciplines, including human and plant biology.

Expedition 43 Commander Terry Virts of NASA, Flight Engineers Anton Shkaplerov of the Russian Federal Space Agency (Roscosmos) and Samantha Cristoforetti of ESA (European Space Agency) touched down at 9:44 a.m. EDT (7:44 p.m., Kazakh time), southeast of the remote town of Dzhezkazgan in Kazakhstan.

ISS Expedition 43 Crew Lands Safely in Kazakhstan

During their time aboard the orbiting laboratory, the crew members participated in a variety of research activities focusing on the effects of microgravity on cells, Earth observation, physical science, and biological and molecular science. Their research included the start of a one-year study into human health management over long-duration space travel with the March arrival of NASA astronaut Scott Kelly and Roscosmos cosmonaut Mikhail Kornienko – the One-Year Crew.

team members welcomed three cargo spacecraft during their stay on station. One Russian ISS Progress cargo vehicle docked to the station in February carrying tons of supplies, and Virts assisted with grapple and connection of two SpaceX Dragon deliveries in January and April -- the company's fifth and sixth NASA-contracted commercial resupply missions.

In preparation for the arrival of U.S. commercial crew vehicles, Virts ventured outside the station for three planned spacewalks to make adjustments for new International Docking Adapters (IDA) that can accommodate the spacecraft. The first IDA is scheduled to arrive on SpaceX’s seventh commercial resupply flight later this month.

The crew also had the opportunity to participate in the demonstration of new, cutting-edge technologies such as the Synthetic Muscle experiment, a test of a new polymer that contracts and expands similar to real muscle. This technology has the potential for future use on robots, enabling them to perform tasks that require considerable dexterity but are too dangerous to be performed by humans in space.

Image above: The Soyuz TMA-15M spacecraft is seen as it lands with Expedition 43 commander Terry Virts of NASA, cosmonaut Anton Shkaplerov of the Russian Federal Space Agency (Roscosmos), and Italian astronaut Samantha Cristoforetti from European Space Agency (ESA) near the town of Zhezkazgan, Kazakhstan on Thursday, June 11, 2015. Image Credits: NASA/Bill Ingalls.

The crew engaged in a number of biological studies, including one investigation to better understand the risks of in-flight infections and another studying the effects microgravity has on bone health during long-duration spaceflight. The Micro-5 study used a small roundworm and a microbe that causes food poisoning in humans to study the risk of infectious diseases in space, which is critical for ensuring crew health, safety and performance during long-duration missions. The Osteo-4 study investigated bone loss in space, which has applications not only for astronauts on long-duration missions, but also for people on Earth affected by osteoporosis and other bone disorders.

The returning crew members will celebrate individual milestones in their space exploration careers. With the completion of his second mission, Virts now has spent 212 days in space. Shkaplerov, having completed his second long-duration mission on the station, has spent 364 days in space. Cristoforetti set a new record for single mission duration by a female astronaut with 199 days in space on her first flight, surpassing NASA astronaut Suni Williams’ previous record of 195 days as a flight engineer on Expeditions 14 and 15 from December 2006 to June 2007.

Expedition 44 now is operating the station with Roscosmos’ Gennady Padalka in command. Flight Engineers Scott Kelly of NASA and Mikhail Kornienko of Roscosmos, are continuing station research and operations until three new crewmates arrive. Kelly and Kornienko are on the first joint U.S.-Russian one-year mission, an important stepping stone on NASA’s journey to Mars.

NASA’s Kjell Lindgren, Roscosmos’ Oleg Kononenko and Japan Aerospace Exploration Agency astronaut Kimiya Yui are scheduled to launch from Kazakhstan in late July.

Related links:

Micro-5 study:

Osteo-4 study:

For more information on the International Space Station and its crews, visit:

Images (mentioned), Video, Text, Credits: NASA/Kathryn Hambleton/Johnson Space Center/Dan Huot/NASA TV/Karen Northon.


Expedition 43 Undocks and Begins Voyage Home

ROSCOSMOS - Soyuz TMA-15M Mission patch.

June 11, 2015

Image above: The Soyuz spacecraft carrying Expedition 43 backs away from the International Space Station after undocking on time. Image Credit: NASA TV.

After spending 199 days aboard the International Space Station, Terry Virts, Samantha Cristoforetti and Anton Shkaplerov undocked from the station at 6:20 a.m. EDT to begin their voyage home. Shkaplerov, the Soyuz commander, is at the controls of the Soyuz TMA-15M spacecraft.

They will perform a separation burn to increase the distance from the station before executing a 4-minute, 35-second deorbit burn at 8:51 a.m. The crew is scheduled to land at 9:43 a.m. southeast of Dzhezkazgan, Kazakhstan.

ISS Expedition 43 Farewell, Hatch Closure and Undocking from the ISS

Video above: At 6:20 a.m. June 11, NASA’s Terry Virts and Flight Engineers Samantha Cristoforetti of ESA (European Space Agency) and Anton Shkaplerov of Roscosmos undocked their Soyuz TMA-15M spacecraft from the International Space Station to return back to Earth and land in Kazakhstan at 9:43 a.m. (7:43 p.m. Kazakh time).  Their return wraps up 199 days in space, during which they traveled more than 84 million miles since their launch from the Baikonur Cosmodrome in Kazakhstan on Nov. 24. Their return date was delayed four weeks to allow Roscosmos to investigate the cause of the loss of the un-piloted Progress 59 cargo ship in late April.

The departure of Virts, Cristoforetti and Shkaplerov marks the end of Expedition 43. The Expedition 44 crew members, Commander Gennady Padalka of the Russian Federal Space Agency (Roscosmos), Scott Kelly of NASA and Mikhail Kornienko of Roscosmos will continue research and maintenance aboard the station and will be joined next month by three additional crew members, NASA astronaut Kjell Lindgren, Russian cosmonaut Oleg Kononenko and Kimiya Yui of the Japan Aerospace Exploration Agency.

NASA Television will air live coverage of the Soyuz TMA-15M deorbit burn and landing beginning at 8:30 a.m. at

Related link:

International Space Station (ISS):

Image (mentioned), Video, Text, Credits: NASA/NASA TV.


mercredi 10 juin 2015

Bright Spots Shine in Newest Dawn Ceres Images

NASA - Dawn Mission patch.

June 10, 2015

New images of dwarf planet Ceres, taken by NASA's Dawn spacecraft, show the cratered surface of this mysterious world in sharper detail than ever before. These are among the first snapshots from Dawn's second mapping orbit, which is 2,700 miles (4,400 kilometers) above Ceres.

Image above: The brightest spots on dwarf planet Ceres are seen in this image taken by NASA's Dawn spacecraft on June 6, 2015. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

The region with the brightest spots is in a crater about 55 miles (90 kilometers) across. The spots consist of many individual bright points of differing sizes, with a central cluster. So far, scientists have found no obvious explanation for their observed locations or brightness levels.

"The bright spots in this configuration make Ceres unique from anything we've seen before in the solar system. The science team is working to understand their source. Reflection from ice is the leading candidate in my mind, but the team continues to consider alternate possibilities, such as salt. With closer views from the new orbit and multiple view angles, we soon will be better able to determine the nature of this enigmatic phenomenon," said Chris Russell, principal investigator for the Dawn mission based at the University of California, Los Angeles.

Image above: A large crater in the southern hemisphere of dwarf planet Ceres is seen in this image taken by NASA's Dawn spacecraft on June 6, 2015. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Numerous other features on Ceres intrigue scientists as they contrast this world with others, including protoplanet Vesta, which Dawn visited for 14 months in 2011 and 2012. Craters abound on both bodies, but Ceres appears to have had more activity on its surface, with evidence of flows, landslides and collapsed structures.

Additionally, new images from Dawn's visible and infrared mapping spectrometer (VIR) show a portion of Ceres' cratered northern hemisphere, taken on May 16, including a true-color view and a temperature image. The temperature image is derived from data in the infrared light range. This instrument is also important in determining the nature of the bright spots.

Image above: Craters in the northern hemisphere of dwarf planet Ceres are seen in this image taken by NASA's Dawn spacecraft on June 6, 2015. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Having arrived in its current orbit on June 3, Dawn will observe the dwarf planet from 2,700 miles (4,400 kilometers) above its surface until June 28. In orbits of about three days each, the spacecraft will conduct intensive observations of Ceres. It will then move toward its next orbit of altitude 900 miles (1,450 kilometers), arriving in early August.

On March 6, 2015, Dawn made history as the first mission to visit a dwarf planet, and the first to orbit two distinct extraterrestrial targets. At its previous target, Vesta, Dawn took tens of thousands of images and made many observations about the body's composition and other properties.

Images above: Images from Dawn's visible and infrared mapping spectrometer (VIR) show a portion of Ceres' cratered northern hemisphere, taken on May 16, 2015. Images Credits: NASA/JPL-Caltech/UCLA/ASI/INAF.

Dawn's mission is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit:

More information about Dawn is available at the following sites: and

Images (mentioned), Text, Credits: NASA/JPL/Elizabeth Landau/Tony Greicius.

Best regards,

Chandra Finds Evidence for Serial Black Hole Eruptions

NASA - Chandra X-ray Observatory patch.

June 10, 2015

Astronomers have used NASA’s Chandra X-ray Observatory to show that, multiple eruptions from a supermassive black hole over 50 million years have rearranged the cosmic landscape at the center of a group of galaxies.

Scientists discovered this history of black hole eruptions by studying NGC 5813, a group of galaxies about 105 million light years from Earth. These Chandra observations are the longest ever obtained of a galaxy group, lasting for just over a week. The Chandra data are shown in this new composite image where the X-rays from Chandra (purple) have been combined with visible light data (red, green and blue).

Galaxy groups are like their larger cousins, galaxy clusters, but instead of containing hundreds or even thousands of galaxies like clusters do, galaxy groups are typically comprised of 50 or fewer galaxies. Like galaxy clusters, groups of galaxies are enveloped by giant amounts of hot gas that emit X-rays.

The erupting supermassive black hole is located in the central galaxy of NGC 5813. The black hole’s spin, coupled with gas spiraling toward the black hole, can produce a rotating, tightly wound vertical tower of magnetic field that flings a large fraction of the inflowing gas away from the vicinity of the black hole in an energetic, high-speed jet.

The researchers were able to determine the length of the black hole’s eruptions by studying cavities, or giant bubbles, in the multi-million degree gas in NGC 5813. These cavities are carved out when jets from the supermassive black hole generate shock waves that push the gas outward and create huge holes.

The latest Chandra observations reveal a third pair of cavities in addition to two that were previously found in NGC 5813, representing three distinct eruptions from the central black hole. (Mouse over the image for annotations of the cavities.) This is the highest number of pairs of cavities ever discovered in either a group or a cluster of galaxies. Similar to how a low-density bubble of air will rise to the surface in water, the giant cavities in NGC 5813 become buoyant and move away from the black hole.

To understand more about the black hole’s history of eruptions, the researchers studied the details of the three pairs of cavities. They found that the amount of energy required to create the pair of cavities closest to the black hole is lower than the energy that produced the older two pairs. However, the rate of energy production, or power, is about the same for all three pairs. This indicates that the eruption associated with the inner pair of cavities is still occurring.

Each of the three pairs of cavities is associated with a shock front, visible as sharp edges in the X-ray image. These shock fronts, akin to sonic booms for a supersonic plane, heat the gas, preventing most of it from cooling and forming large numbers of new stars.

Close study of the shock fronts reveals that they are actually slightly broadened, or blurred, rather than being very sharp. This may be caused by turbulence in the hot gas. Assuming this is the case, the authors found a turbulent velocity – that is, the average speed of random motions of the gas − of about 160,000 miles per hour (258,000 kilometers per hour). This is consistent with the predictions of theoretical models and estimates based on X-ray observations of the hot gas in other groups and clusters.

Chandra X-ray Observatory

A paper describing these results was published in the June 1st, 2015 issue of The Astrophysical Journal and is available online. The first author is Scott Randall from the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, MA and the co-authors are Paul Nulsen, Christine Jones, William Forman and Esra Bulbul from CfA; Tracey Clarke from the Naval Research Laboratory in Washington DC; Ralph Kraft from CfA; Elizabeth Blanton from Boston University in Boston, MA; Lawrence David from CfA; Norbert Werner from Stanford University in Stanford, CA; Ming Sun from University of Alabama in Huntsville, AL; Megan Donahue from Michigan State University in East Lansing, MI; Simona Giacintucci from University of Maryland in College Park, MD and Aurora Simionescu from the Japan Aerospace Exploration Agency in Kanagawa, Japan.

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for the agency's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Related link:

June 1st, 2015 issue of The Astrophysical Journal:

Read More from NASA's Chandra X-ray Observatory:

Images Credits: X-ray: NASA/CXC/SAO/S.Randall et al., Optical: SDSS/Text, Credits: NASA/Marshall Space Flight Center/Janet Anderson/Chandra X-ray Center/Megan Watzke/Jennifer Harbaugh.


New Hubble image of galaxy NGC 6503

ESA - Hubble Space Telescope logo.

10 June 2015

Lost in space

NGC 6503

Although the Universe may seem spacious most galaxies are clumped together in groups or clusters and a neighbour is never far away. But this galaxy, known as NGC 6503, has found itself in a lonely position, shown here at the edge of a strangely empty patch of space called the Local Void. This new NASA/ESA Hubble Space Telescope image shows a very rich set of colours, adding to the detail seen in previous images.

NGC 6503 is only some 18 million light-years away from us in the constellation of Draco (The Dragon), making it one of the closest neighbours from our Local Group. It spans some 30 000 light-years, about a third of the size of the Milky Way. The galaxy’s lonely location led stargazer Stephen James O'Meara to dub it the “Lost-In-Space galaxy” in his 2007 book Hidden Treasures [1].

This galaxy does not just offer poetic inspiration; it is also the subject of ongoing research. The Hubble Legacy ExtraGalactic UV Survey (LEGUS) is exploring a sample of nearby galaxies, including NGC 6503, to study their shape, internal structure, and the properties and behaviour of their stars. This survey uses 154 orbits of time on Hubble; by contrast, a typical Hubble observing programme lasts from a few to a few tens of orbits.

The area around NGC 6503 (ground-based image)

The Local Void is a patch of space thought to be about 150 million light-years across that seems to be curiously devoid of galaxies. Astronomers using Hubble discovered that the emptiness of this region has quite an effect on the space around us — the Milky Way is being strongly pulled away from it by the gentle but relentless tug of other nearby galaxies.

NGC 6503 lies right on the edge of this void. It has an almost non-existent central bulge surrounded by a massive halo of gas. The galaxy’s central region is a good example of something known as a “low ionisation nuclear emission region”, or LINER. These are less luminous than some of the brightest galaxies. Emission from NGC 6503’s heart is believed to be the result of a starved black hole that is only just being kept active, receiving a very small amount of infalling gas to keep its large appetite at bay.

Zooming in on NGC 6503

A previous image of NGC 6503 was released as a Hubble Picture of the Week back in 2010, taken by Hubble’s Advanced Camera for Surveys. However, this new image, taken using Hubble’s Wide Field Camera 3 (WFC3), shows NGC 6503 in striking detail and with a richer set of colours. Bright red patches of gas can be seen scattered through its swirling spiral arms, mixed with bright blue regions that contain newly-forming stars. Dark brown dust lanes snake across the galaxy’s bright arms and centre, giving it a mottled appearance.

Installed in 2009 during the final Hubble servicing mission, SM4, WFC3 covers a wide range of the spectrum, from the ultraviolet all the way through to the near-infrared. Compared with its predecessor, the Wide Field and Planetary Camera 2 (WFPC2), it offers improved resolution and a wider field of view, and has led to a large number of stunning Hubble images since its installation.

Panning across NGC 6503


[1] This was also the name of a Hubble image processing competition run in 2012, which invited people to scour the Hubble archive for interesting and beautiful observations.
Notes for editors

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

Related links:

The Hubble Legacy ExtraGalactic UV Survey (LEGUS):

Hubble’s Advanced Camera for Surveys:

Wide Field and Planetary Camera 2 (WFPC2):


Link to hubblesite release:

Images of Hubble:

Hubblecast 40: Wide Field Camera 3 - Hubble's New Miracle Camera:

Candidate Active Nuclei in Late-type Spiral Galaxies:

Images, Text, Credits: NASA, ESA, D. Calzetti (University of Massachusetts, USA) and H. Ford (Johns Hopkins University, USA)/Digitized Sky Survey 2 (Acknowledgement: Davide De Martin)/Videos: NASA & ESA.


A Celestial Butterfly Emerges from its Dusty Cocoon

ESO - European Southern Observatory logo.

10 June 2015

SPHERE reveals earliest stage of planetary nebula formation

VLT/SPHERE image of the star L2 Puppis and its surroundings

Some of the sharpest images ever made with ESO’s Very Large Telescope (VLT) have, for the first time, revealed what appears to be an ageing star giving birth to a butterfly-like planetary nebula. These observations of the red giant star L2 Puppis, from the ZIMPOL mode of the newly installed SPHERE instrument, also clearly showed a close companion. The dying stages of stars continue to pose astronomers with many riddles, and the origin of such bipolar nebulae, with their complex and alluring hourglass figures, doubly so. This new imaging mode means that the VLT is currently the sharpest astronomical direct imaging instrument in existence.

At about 200 light-years away, L2 Puppis is one of the closest red giants to Earth known to be entering its final stages of life. The new observations with the ZIMPOL mode of SPHERE were made in visible light using extreme adaptive optics, which corrects images to a much higher degree than standard adaptive optics, allowing faint objects and structures close to bright sources of light to be seen in greater detail. They are the first published results from this mode and the most detailed of such a star.

VLT/SPHERE and NACO image of the star L2 Puppis and its surroundings

ZIMPOL can produce images that are three times sharper than those from the NASA/ESA Hubble Space Telescope, and the new observations show the dust that surrounds L2 Puppis in exquisite detail [1]. They confirm earlier findings, made using NACO, of the dust being arranged in a disc, which from Earth is seen almost completely edge-on, but provide a much more detailed view. The polarisation information from ZIMPOL also allowed the team to construct a three dimensional model of the dust structures [2].

The astronomers found the dust disc to begin about 900 million kilometres from the star — slightly farther than the distance from the Sun to Jupiter — and discovered that it flares outwards, creating a symmetrical, funnel-like shape surrounding the star. The team also observed a second source of light about 300 million kilometres — twice the distance from Earth to the Sun — from L2 Puppis. This very close companion star is likely to be another red giant of slightly lower mass, but less evolved.

The star L2 Puppis in the constellation of Puppis

The combination of a large amount of dust surrounding a slowly dying star, along with the presence of a companion star, mean that this is exactly the type of system expected to create a bipolar planetary nebula. These three elements seem to be necessary, but a considerable amount of good fortune is also still required if they are to lead to the subsequent emergence of a celestial butterfly from this dusty chrysalis.

Lead author of the paper, Pierre Kervella, explains: “The origin of bipolar planetary nebulae is one of the great classic problems of modern astrophysics, especially the question of how, exactly, stars return their valuable payload of metals back into space — an important process, because it is this material that will be used to produce later generations of planetary systems.”

Wide-field view of the sky around the red giant star L2 Puppis

In addition to L2 Puppis’s flared disc, the team found two cones of material, which rise out perpendicularly to the disc. Importantly, within these cones, they found two long, slowly curving plumes of material. From the origin points of these plumes, the team deduces that one is likely to be the product of the interaction between the material from L2 Puppis and the companions star’s wind and radiation pressure, while the other is likely to have arisen from a collision between the stellar winds from the two stars, or be the result of an accretion disc around the companion star.

Although much is still to be understood, there are two leading theories of bipolar planetary nebulae, both relying on the existence of a binary star system [3]. The new observations suggest that both of these processes are in action around L2 Puppis, making it appear very probable that the pair of stars will, in time, give birth to a butterfly.

Zooming in on the red giant star L2 Puppis

Pierre Kervella concludes: “With the companion star orbiting L2 Puppis only every few years, we expect to see how the companion star shapes the red giant’s disc. It will be possible to follow the evolution of the dust features around the star in real time — an extremely rare and exciting prospect.”


[1] SPHERE/ZIMPOL use extreme adaptive optics to create diffraction-limited images, which come a lot closer than previous adaptive optics instruments to achieving the theoretical limit of the telescope if there were no atmosphere. Extreme adaptive optics also allows much fainter objects to be seen very close to a bright star. These images are also taken in visible light — shorter wavelengths than the near-infrared regime, where most earlier adaptive optics imaging was performed. These two factors result in significantly sharper images than earlier VLT images. Even higher spatial resolution has been achieved with VLTI, but the interferometer does not create images directly.

[2] The dust in the disc was very efficient at scattering the stars’ light towards Earth and polarising it, a feature that the team could use to create a three-dimensional map of the envelope using both ZIMPOL and NACO data and a disc model based on the RADMC-3D radiative transfer modeling tool, which uses a given set of parameters for the dust to simulate photons propagating through it.

[3] The first theory is that the dust produced by the primary, dying star’s stellar wind is confined to a ring-like orbit about the star by the stellar winds and radiation pressure produced by the companion star. Any further mass lost from the main star is then funneled, or collimated, by this disc, forcing the material to move outwards in two opposing columns perpendicular to the disc.

The second holds that most of the material being ejected by the dying star is accreted by its nearby companion, which begins to form an accretion disc and a pair of powerful jets. Any remaining material is pushed away by the dying star’s stellar winds, forming an encompassing cloud of gas and dust, as would normally occur in a single star system. The companion star’s newly created bipolar jets, moving with much greater force than the stellar winds of the dying star, then carve dual cavities through the surrounding dust, resulting in the characteristic appearance of a bipolar planetary nebula.

More information:

This research was presented in a paper entitled “The dust disk and companion of the nearby AGB star L2 Puppis”, by P. Kervella, et al., to appear in the journal Astronomy & Astrophysics on 10 June 2015.

The team is composed of P. Kervella (Unidad Mixta Internacional Franco-Chilena de Astronomía, CNRS/INSU, France; Departamento de Astronomía, Universidad de Chile, Santiago, Chile; Observatoire de Paris, LESIA, France; Université Paris-Diderot, Meudon, France), M. Montargès (LESIA, France;  Institut de Radio-Astronomie Millimétrique, St Martin d’Hères, France), E. Lagadec (Laboratoire Lagrange, Université de Nice-Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, Nice, France), S. T. Ridgway (National Optical Astronomy Observatories, Tucson, Arizona, USA), X. Haubois (ESO, Santiago, Chile), J. H. Girard (ESO, Chile), K. Ohnaka (Instituto de Astronomía, Universidad Católica del Norte, Antofagasta, Chile), G. Perrin (Observatoire de Paris, LESIA, France) and A. Gallenne (Universidad de Concepción, Departamento de Astronomía, Concepción, Chile).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.


Research paper:

Photos of the VLT:

ESOcast on ZIMPOL/SPHERE and polarimetry:

More information about SPHERE:

Images, Text, Credits: ESO/P. Kervella/IAU and Sky & Telescope/Digitized Sky Survey 2/Video: ESO/P. Kervella/N. Risinger ( Music: Johan B. Monell (


mardi 9 juin 2015

Roscosmos Announces New Soyuz/Progress Launch Dates

ROSCOSMOS - Russian Vehicles patch.

June 9, 2015

Station managers from Roscosmos have announced new Soyuz and Progress spacecraft launch dates through the end of the year. Meanwhile, the six member Expedition 43 crew on orbit has a packed schedule of homecoming preparations, science and maintenance.

Three Soyuz crew missions to the International Space Station have been given new launch dates. The next Soyuz mission carrying three Expedition 44/45 crew members is scheduled sometime between July 23 and 25. A Soyuz taxi flight that will bring up Flight Engineer Sergey Volkov and return Commander Gennady Padalka is scheduled for launch Sept. 1. Volkov will be accompanied by European astronaut Andres Mogensen and a third crew member yet to be announced. The Expedition 46/47 trio will launch Dec. 15.

Three Progress cargo missions were also rescheduled. The first resupply mission is set for July 3 and the next two are planned for Sept. 21 and Nov. 21.

Image above: he Soyuz TMA-16M spacecraft launches to the International Space Station. Photo Credit (NASA/Bill Ingalls).

In space, Commander Terry Virts and Flight Engineers Anton Shkaplerov and Samantha Cristoforetti are packing their Soyuz TMA-15M and getting ready for Thursday’s undocking and landing. The homebound trio will undock at 6:20 a.m. EDT and land in Kazakhstan at 9:43 a.m.

A wide array of experiment work that observes how humans adapt to living in space took place Tuesday. One-Year crew member Scott Kelly collected his saliva and blood samples for the Twins study. Scientists are comparing his body in weightlessness with his Earth-bound identical twin brother and ex-astronaut Mark Kelly. The crew prepared for ultrasound scans so they could explore cardiovascular health before, during and after a space mission for the Cardio Ox study. The crew also studied how astronauts operate and repair interactive, touch-based and sensitive technologies in space for the Fine Motor Skills study.

Related links:

ROSCOSMOS Press Release:

ISS Expedition 44/45:

ISS Expedition 46/47:

Twins study:

Cardio Ox study:

Fine Motor Skills study:

For more information about the International Space Station, visit:

Image (mentioned), Text, Credit: NASA.


Seeing the invisible: Event displays in particle physics

CERN - European Organization for Nuclear Research logo.

June 9, 2015

Subatomic particles are far too tiny to see, so over the years physicists have devised ingenious ways to detect and visualise them, often forming beautiful patterns and pictures in the process. 

Image above: This artistically enhanced image was produced by the Big European Bubble Chamber (BEBC), which started up at CERN in 1973. Charged particles passing through a chamber filled with hydrogen-neon liquid leave bubbles along their paths (Image: BEBC).

From early experiments with cloud chambers to state-of-the-art animations of Higgs-boson decays, data visualisation in particle physics has come a long way. Here are just a few of the most striking images of particle interactions - or "event displays" - from over the years.

Cloud chambers

Some detectors can reveal subatomic particles by making their tracks visible to the naked eye. The first such detector was the cloud chamber, developed in 1911 by Charles Thomson Rees Wilson (link is external) in Cambridge, UK – an invention for which he received the 1927 Nobel prize in physics. 

A cloud chamber is a box containing a supersaturated vapour. As charged particles pass through, they ionise the vapour, which condenses to form droplets on the ions. The tracks of the particles become visible as trails of droplets, which can be photographed. During the first half of the 20th century, experiments that looked at cosmic rays passing through cloud chambers revealed the existence of several fundamental particles, including the positron, the muon and the first strange particles.

Image above: This photograph, taken in 1932 by American physicist Carl D Anderson (link is external), shows a track left by the first positron ever identified. The line across the centre of the image is a 6 millimetre lead plate separating the upper and lower halves of the chamber. (Image: Wikimedia Commons).

Today at CERN, the Cosmics Leaving Outdoor Droplets (CLOUD) experiment uses a special cloud chamber to study the possible link between galactic cosmic rays and cloud formation. The CLOUD chamber is used both to grow the aerosol particle seeds for cloud droplets and also to form the clouds themselves. "CLOUD uses the same principle of adiabatic cooling of humid air as in the original Wilson cloud chamber," says Jasper Kirkby of the CLOUD experiment. "But the conditions are chosen to reproduce natural clouds, involving only small water-vapour supersaturations, so particle tracks do not form."

Image above: "Banana plot" showing the formation of bursts of aerosol particles in the CLOUD chamber when a beam from the CERN Proton Synchrotron crosses the chamber. After about five hours the particles have grown to sizes sufficient to begin to seed cloud droplets (Image: Jasper Kirkby/CLOUD).

Cloud chambers can also be found at CERN's S'Cool lab, where students build their own devices to see how charged particles can form droplets in the vapour.

Bubble chambers

After World War II, as higher-energy particle accelerators became available, the cloud chamber was gradually replaced by the bubble chamber. Donald A. Glaser invented the bubble chamber 1952, for which he was awarded the 1960 Nobel prize in physics. It works on a similar principle to the cloud chamber, but the tracks are made visible as a trail of bubbles in a superheated liquid that is about to boil rather than in a vapour.

Image above: This photograph of tracks in the Gargamelle bubble chamber provided the first confirmation of the weak neutral-current interaction. A neutrino, which leaves no track, enters from the top and knocks on an electron, giving it enough energy to create the small downward “shower” of curling tracks. The Gargamelle collaboration announced the discovery of the weak neutral current in July 1973 (Image: Gargamelle/CERN).

CERN's famous bubble chamber Gargamelle was instrumental in the 1973 discovery of weak neutral currents. The discovery confirmed the reprediction of such currents by electroweak theory, which treated that the weak force and the electromagnetic force as different facets of the same interaction.

Bubbles of data

In cloud and bubble chambers, the data acquisition and event display were practically the same. Other (non-visual) particle detectors triggered cameras to take photographs in the chamber, and these were later projected onto a special table for analysis. At CERN in the 1960s, people worked in shifts round the clock to analyse such images, sifting through many thousands to find the events that physicists found interesting. They then measured the length and direction of the interesting particle tracks.

Image above: A cosmic-muon track in the spark chambers of a neutrino experiment at the Proton Synchrotron at CERN in 1963 (Image: CERN).

However, a bubble chamber is sensitive to particles passing through only when its contents are superheated after rapid expansion. Bubbles form at this point and the chamber must be recompressed to stop the bubble growth for a picture. This limits the rate at which events can be collected. For instance, the huge Big European Bubble Chamber (BEBC), which started operation at CERN in 1973, took 6.3 million pictures during its 11 years of service. Current experiments at the Large Hadron Collider (LHC) record this number of events in less than 2 hours.

The spark chamber improved on the bubble chamber as interactions could be captured much more rapidly. In a spark chamber, particles pass through an inert gas such as neon, forming tracks. A voltage is applied to alternate plates in the chamber, causing a trail of sparks to flash across the gas.

Charpak and the move to digital

Though spark chambers were faster than bubble chambers, they did not provide the detail – the resolution – that a bubble chamber could.

In 1968 at CERN, the French physicist Georges Charpak developed the “multiwire proportional chamber” to overcome the limitations of spark chambers, both in speed and their resolution. Charpak's chamber was basically a gas-filled box with a large number of parallel detector wires, each connected to individual transistor amplifiers. Now there was no need for a spark; a detector wire connected to an amplifier can detect a much smaller effect. Linked to a computer, Charpak’s chamber could achieve a counting rate a thousand times better than existing detectors.

Charpak's invention, for which he received the 1992 Nobel prize in physics, revolutionized particle detection. It made data acquisition quick, automated and electronic. As a result, it also changed the nature of event displays.

Photographs were no longer the only way to visualise particle tracks in detail; rather, event displays became visual representations of patterns of digital signals that corresponded to the particles produced in an interaction. Moreover, the event display can be made to show only those tracks that physicists find interesting. So the display has become a visual representation of the most interesting part of what happened in the detector.

Video above: Proton-antiproton collisions seen in the UA1 detector at CERN, 1983. The computer system Megatek rendered the displays (Video: CERN).

As detectors became more complex and able to detect many more particles at a time, the amount of data associated with each event increased and event displays became correspondingly more intricate. Researchers developed software that could interpret the patterns of signals picked up by detectors and recreate them as images in 3D space.

The advent of computer colour screens in the late 1970s allowed physicists for the first time to render event displays in full colour, leading to discussions about which were the most suitable hues to represent different particles. Coupled with computer systems such as the Megatek, these displays could even be manipulated in 3D.

Digital data

Tom McCauley of the University of Notre Dame in the US makes event displays for the CMS experiment at CERN. "The days when data acquisition and event display were practically the same are no more," he says. "The LHC produces hundreds of millions of proton-proton collisions per second, which produce very complex events, and the detectors are correspondingly sophisticated. The displays reflect this complexity but are useful since they can provide a visual summary of what happened; you can describe geography and a route with words, but sometimes nothing beats a map with a line marking the way."

Image above: Protons collide at 13 teraelectronvolts in this event display from 3 June 2015, sending showers of particles through the CMS experiment (Image: CMS).

These days to create a display, experiment teams run software that converts the data into graphical objects. These graphics are then rendered in a specialised application. The details of the display – views, colours, what is shown and what is not – depend on the particular use-case.

Physicists at CERN use event displays for viewing geometry, developing algorithms and detector monitoring. The displays are also frequently used in communicating LHC science to the general public and to the media. And the images continue to become increasingly detailed.

Image above: Protons collide at 13 teraelectronvolts on 3 June 2015 inside the ALICE detector (Image: ALICE).

"These days thanks to advances in computing we're capable of so much more graphics-wise and can run on many different devices and platforms," says McCauley. "I find it amazing that today I can run an event-display application on my phone!"

The nature and complexity of event displays, and how they are generated in the first place, have changed considerably since Wilson's first cloud-chamber photos in 1911. But one thing has not changed.

"Conveying the physics accurately is always the primary consideration," says McCauley.


CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related links:

Charles Thomson Rees Wilson:

Cosmics Leaving Outdoor Droplets (CLOUD) experiment:

CERN's S'Cool lab:

For more information about the European Organization for Nuclear Research (CERN), visit:

Images (mentioned), Video (mentioned), Text, Credits: CERN/Cian O'Luanaigh.

Best regards,