vendredi 31 août 2018

Hunting for dark quarks

CERN - European Organization for Nuclear Research logo.

31 Aug 2018

A proton–proton collision event with two emerging-jet candidates. (Image: CMS/CERN)

Quarks are the smallest particles that we know of. In fact, according to the Standard Model of particle physics, which describes all known particles and their interactions, quarks should be infinitely small. If that’s not mind-boggling enough, enter dark quarks – hypothetical particles that have been proposed to explain dark matter, an invisible form of matter that fills the universe and holds the Milky Way and other galaxies together.

In a recent study, the CMS collaboration describes how it has sifted through data from the Large Hadron Collider (LHC) to try and spot dark quarks. Although the search came up empty-handed, it allowed the team to inch closer to the parent particles from which dark quarks may originate.

One compelling theory extends the Standard Model to explain why the observed mass densities of normal matter and dark matter are similar. It does so by invoking the existence of dark quarks that interact with ordinary quarks via a mediator particle. If such mediator particles were produced in pairs in a proton–proton collision, each mediator particle of the pair would transform into a normal quark and a dark quark, both of which would produce a spray, or “jet”, of particles called hadrons, composed of quarks or dark quarks. In total, there would be two jets of regular hadrons originating from the collision point, and two “emerging” jets that would emerge a distance away from the collision point because dark hadrons would take some time to decay into visible particles.

In their study, the CMS researchers looked through data from proton–proton collisions collected at the LHC at an energy of 13 TeV to search for instances, or “events”, in which such mediator particles and associated emerging jets might occur. They used two distinguishing features to identify emerging jets and pick them out from a background of events that are expected to mimic their traits.

Large Hadron Collider (LHC). Animation Credit: CERN

The team found no strong evidence for the existence of such emerging jets, but the data allowed them to exclude masses for the hypothetical mediator particle of 400–1250 GeV for dark pions that travel for lengths between 5 and 225 mm before they decay. The results are the first from a dedicated search for such mediator particles and jets.


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:

Standard Model of particle physics:

Dark matter:

CMS experiment:

Large Hadron Collider (LHC):

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

Image (mentioned), Animation (mentioned), Text, Credits: CERN/Achintya Rao.


AWAKE successfully accelerates electrons

CERN - European Organization for Nuclear Research logo.

31 Aug 2018

Early in the morning on Saturday, 26 May 2018, the AWAKE collaboration at CERN successfully accelerated electrons for the first time using a wakefield generated by protons zipping through a plasma. A paper describing this important result was published in the journal Nature. The electrons were accelerated by a factor of around 100 over a length of 10 metres: they were externally injected into AWAKE at an energy of around 19 MeV (million electronvolts) and attained an energy of almost 2 GeV (billion electronvolts). Although still at a very early stage of development, the use of plasma wakefields could drastically reduce the sizes, and therefore the costs, of the accelerators needed to achieve the high-energy collisions that physicists use to probe the fundamental laws of nature. The first demonstration of electron acceleration in AWAKE comes only five years after CERN approved the project in 2013 and is an important first step towards realising this vision.

AWAKE's electron beam line (Image: Maximilien Brice/Julien Ordan/CERN)

AWAKE, which stands for “Advanced WAKEfield Experiment”, is a proof-of-principle R&D project investigating the use of protons to drive plasma wakefields for accelerating electrons to higher energies than can be achieved using conventional technologies. Traditional accelerators use what are known as radio-frequency (RF) cavities to kick the particle beams to higher energies. This involves alternating the electrical polarity of positively and negatively charged zones within the RF cavity, with the combination of attraction and repulsion accelerating the particles within the cavity. By contrast, in wakefield accelerators, the particles get accelerated by “surfing” on top of the plasma wave (or wakefield) that contains similar zones of positive and negative charges.

Plasma wakefields themselves are not new ideas; they were first proposed in the late 1970s. “Wakefield accelerators have two different beams: the beam of particles that is the target for the acceleration is known as a ‘witness beam’, while the beam that generates the wakefield itself is known as the ‘drive beam’,” explains Allen Caldwell, spokesperson of the AWAKE collaboration. Previous examples of wakefield acceleration have relied on using electrons or lasers for the drive beam. AWAKE is the first experiment to use protons for the drive beam, and CERN provides the perfect opportunity to try the concept. Drive beams of protons penetrate deeper into the plasma than drive beams of electrons and lasers. “Therefore,” Caldwell adds, “wakefield accelerators relying on protons for their drive beams can accelerate their witness beams for a greater distance, consequently allowing them to attain higher energies.”

AWAKE gets its drive-protons from the Super Proton Synchrotron (SPS), which is the last accelerator in the chain that delivers protons to the Large Hadron Collider (LHC). Protons from the SPS, travelling with an energy of 400 GeV, are injected into a so-called “plasma cell” of AWAKE, which contains Rubidium gas uniformly heated to around 200 ºC. These protons are accompanied by a laser pulse that transforms the Rubidium gas into a plasma – a special state of ionised gas – by ejecting electrons from the gas atoms. As this drive beam of positively charged protons travels through the plasma, it causes the otherwise-randomly-distributed negatively charged electrons within the plasma to oscillate in a wavelike pattern, much like a ship moving through the water generates oscillations in its wake. Witness-electrons are then injected at an angle into this oscillating plasma at relatively low energies and “ride” the plasma wave to get accelerated. At the other end of the plasma, a dipole magnet bends the incoming electrons onto a detector. “The magnetic field of the dipole can be adjusted so that only electrons with a specific energy go through to the detector and give a signal at a particular location inside it,” says Matthew Wing, deputy spokesperson of AWAKE, who is also responsible for this apparatus, known as the electron spectrometer. “This is how we were able to determine that the accelerated electrons reached an energy of up to 2 GeV.”

The strength at which an accelerator can accelerate a particle beam per unit of length is known as its acceleration gradient and is measured in volts-per-metre (V/m). The greater the acceleration gradient, the more effective the acceleration. The Large Electron-Positron collider (LEP), which operated at CERN between 1989 and 2000, used conventional RF cavities and had a nominal acceleration gradient of 6 MV/m. “By accelerating electrons to 2 GeV in just 10 metres, AWAKE has demonstrated that it can achieve an average gradient of around 200 MV/m,” says Edda Gschwendtner, technical coordinator and CERN project leader for AWAKE. Gschwendtner and colleagues are aiming to attain an eventual acceleration gradient of around 1000 MV/m (or 1 GV/m).

AWAKE: Interview with Edda Gschwendtner, Technical Coordinator and CERN Project Leader

Video above: CERN project leader for AWAKE, Edda Gschwendtner, explains how the experiment accelerated electrons for the first time (Video: CERN).

AWAKE has made rapid progress since its inception. Civil-engineering works for the project began in 2014, and the plasma cell was installed in early 2016 in the tunnel formerly used by part of the CNGS facility at CERN. A few months later, the first drive beams of protons were injected into the plasma cell to commission the experimental apparatus, and a proton-driven wakefield was observed for the first time in late 2016. In late 2017, the electron source, electron beam line and electron spectrometer were installed in the AWAKE facility to complete the preparatory phase.

Now that they have demonstrated the ability to accelerate electrons using a proton-driven plasma wakefield, the AWAKE team is looking to the future. “Our next steps include plans for delivering accelerated electrons to a physics experiment and extending the project with a full-fledged physics programme of its own,” notes Patric Muggli, physics coordinator for AWAKE. AWAKE will continue testing the wakefield-acceleration of electrons for the rest of 2018, after which the entire accelerator complex at CERN will undergo a two-year shutdown for upgrades and maintenance. Gschwendtner is optimistic: “We are looking forward to obtaining more results from our experiment to demonstrate the scope of plasma wakefields as the basis for future particle accelerators.”


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:

Journal Nature:

AWAKE collaboration at CERN:

Super Proton Synchrotron (SPS):


Large Hadron Collider (LHC):

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

Image (mentioned), Video (mentioned), Text, Credits: CERN/Achintya Rao.

Best regards,

Crew Plans Quiet Labor Day Weekend After Repair Work

ISS - Expedition 56 Mission patch.

August 31, 2018

The Expedition 56 crew resumed a regular schedule of work Friday on the International Space Station after spending the day Thursday locating and repairing a leak in the upper section of one of the two Russian Soyuz vehicles attached to the complex.

Image above: The Soyuz MS-09 crew spacecraft from Roscosmos is pictured docked to the Rassvet module as the International Space Station was flying into an orbital night period. Image Credit: NASA.

With the station’s cabin pressure holding steady, most of the crew pressed ahead with a variety of scientific experiments. Station Commander Drew Feustel of NASA prepared tools to be used in a pair of spacewalks late next month to complete the change out of batteries on the port truss of the outpost. Six new lithium-ion batteries will be transported to the station in September on the Japanese HTV Transfer Vehicle, or HTV-7 cargo craft, that will replace a dozen older nickel-hydrogen batteries in a duplication of work conducted last year on the station’s starboard truss.

Flight controllers at the Mission Control Centers in Houston and Moscow, meanwhile, continued to monitor pressure levels on the station following the patching of a small hole Thursday in the orbital module, or upper portion of the Soyuz MS-09 spacecraft. The Soyuz is docked to the Rassvet module on the Earth-facing side of the Russian segment. The tiny hole created a slight loss in pressure late Wednesday and early Thursday before it was repaired by Soyuz commander Sergey Prokopyev of Roscosmos.

International Space Station (ISS). Animation Credit: NASA

The crew plans a quiet weekend before embarking on a busy schedule of research and routine maintenance work next week.

Related links:

Expedition 56:

Space Station Research and Technology:

International Space Station (ISS):

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards,

Hubble’s Lucky Observation of an Enigmatic Cloud

NASA - Hubble Space Telescope patch.

Aug. 31, 2018

The little-known nebula IRAS 05437+2502 billows out among the bright stars and dark dust clouds that surround it in this striking image from the Hubble Space Telescope. It is located in the constellation of Taurus (the Bull), close to the central plane of our Milky Way galaxy. Unlike many of Hubble’s targets, this object has not been studied in detail and its exact nature is unclear. At first glance it appears to be a small, rather isolated region of star formation, and one might assume that the effects of fierce ultraviolet radiation from bright, young stars probably were the cause of the eye-catching shapes of the gas. However, the bright, boomerang-shaped feature may tell a more dramatic tale. The interaction of a high-velocity young star with the cloud of gas and dust may have created this unusually sharp-edged, bright arc. Such a reckless star would have been ejected from the distant young cluster where it was born and would travel at 200,000 kilometers per hour (124,000 miles per hour) or more through the nebula.

This faint cloud was originally discovered in 1983 by the Infrared Astronomical Satellite (IRAS), the first space telescope to survey the whole sky in infrared light. IRAS was run by the United States, the Netherlands, and the United Kingdom and found huge numbers of new objects that were invisible from the ground.

This image was taken with the Wide Field Channel of the Advanced Camera for Surveys on Hubble. It was part of a “snapshot” survey. These are observations that are fitted into Hubble’s busy schedule when possible, without any guarantee that the observation will take place — so it was fortunate that the observation was made at all. This picture was created from images taken through yellow and near-infrared filters.

Hubble Space Telescope (HST)

For more information about Hubble, visit:

Image, Animation, Credits: ESA/Hubble, R. Sahai and NASA/Text Credits: European Space Agency (ESA)/NASA/Karl Hille.

Best regards,

Space Station Science Highlights: Week of August 27, 2018

ISS - Expedition 56 Mission patch.

Aug. 31, 2018

This week, NASA astronaut Ricky Arnold became the first person to sequence RNA in space, another molecular milestone aboard the orbiting laboratory. Arnold’s work was part of a robust week of science, leading into a new, busy month for the Expedition 56 crew aboard the International Space Station. Japan is preparing to launch its seventh resupply mission, Kounotori HTV-7 on September 10, and three astronauts are gearing up for two spacewalks next month.

Image above: NASA astronaut Serena M. Auñón-Chancellor works with the Bone Densitometer. Densitometry measures the mass per unit volume (density) of minerals in bone. Quantitative measures of bone loss in mice during space flight are necessary for the development of countermeasures for human crew members, as well as for bone-loss syndromes on Earth. Image Credit: NASA.

This week, crew members conducted hours of science and conducted repair work after a small leak was detected in the orbital compartment, or upper section, of the Soyuz MS-09 spacecraft attached to the Rassvet module of the Russian segment of the station. The station’s cabin pressure is holding steady following the repair.

Read more details about the scientific work conducted aboard your orbiting laboratory:

RNA sequenced in space for the first time

Much of present-day science focuses on exploring the molecular world. A primary tool is DNA sequencing, performed for the first time on the orbiting lab in August 2016.

Image above: NASA astronaut Ricky Arnold conducts the WetLab-2 Parra investigation. WetLab-2 Parra tests a passive method to remove air bubbles from a liquid sample. Image Credit: NASA.

Biomolecule Extraction and Sequencing Technology (BEST) seeks to advance use of sequencing in space in three ways: identifying microbes aboard the space station that current methods cannot detect, assessing microbial mutations in the genome because of spaceflight and performing direct RNA sequencing.

Animation above: NASA astronaut Ricky Arnold loads RNA into the minION device as a part of the BEST investigation. BEST seeks to advance DNA and RNA sequencing in space. Animation Credit: NASA.

This week, Arnold became the first person to sequence RNA in space. Within the first few minutes, more than 15,000 RNA molecules had been sequenced, matching and surpassing many ground sequencing runs. The run continued for 48 hours.

Learn more about the BEST investigation here:

Station catches glimpses of the moon

Communication is a vital piece of long-duration, deep-space exploration. If a spacecraft loses communication with the ground or with NASA’s Deep Space Network, its crew must navigate just as ancient mariners did, using the moon and stars. The Moon Imagery investigation collects pictures of the moon from the station, and then uses them to calibrate navigation software to guide the Orion Multi-Purpose Crew Vehicle, in case its transponder-based navigation capability is lost. Crewmembers photograph the moon’s phases during one 29-day cycle, providing images of varying brightness to calibrate Orion’s camera software.

This week, crew members took photographs of the full moon during a day pass and downlinked them for analysis on the ground.

Get a grip: Investigation studies motor control in microgravity environment

Microgravity provides a unique environment to study dexterous manipulation. The European Space Agency’s GRIP investigation studies long-duration spaceflight effects on the abilities of human subjects to regulate grip force and upper limb trajectories when manipulating objects using different kinds of movements (i.e.oscillatory movements, rapid discrete movements and tapping gestures).

Animation above: This week, the DLR Earth Sensing Imaging Spectrometer (DESIS) was checked out to be powered up. DESIS verifies and enhances the use of space-based hyperspectral imaging capabilities for Earth remote sensing, and provides an instrument which produces high value hyperspectral imagery for Teledyne Brown Engineering (TBE) commercial purposes. Animation Credit: NASA.

Data collected from this investigation may provide insight into potential hazards for astronauts as they manipulate objects in different gravitational environments. It could alsosupport design and control of haptic interfaces to be used in challenging environments and provide information about motor control that potentially will be useful for the evaluation and rehabilitation of patients with neurological diseases.

Space to Ground: Potential Game Changer: 08/31/2018

This week, the crew completed the first of three GRIP operations in the seated position.

Other work was done on these investigations: BPC-1, SpaceTex-2, Metabolic Space, Lighting Effects, Cerebral Autoregulation, BCAT-CS, CASIS PCG-13, CEO, ISS HAM, Rodent Research-7, SCAN Testbed, SPHERES SmoothNav, ACME CLD Flame, DESIS, MSRR, Tropical Cyclone, Cold Atom Lab, HDEV, Bone Densitometer, WetLab-2 Parra, and Food Acceptability.

Related links:

Biomolecule Extraction and Sequencing Technology (BEST):

NASA’s Deep Space Network:

Moon Imagery:




Metabolic Space:

Lighting Effects:

Cerebral Autoregulation:





Rodent Research-7:

SCAN Testbed:

SPHERES SmoothNav:



Tropical Cyclone:

Cold Atom Lab:


Bone Densitometer:

WetLab-2 Parra:

Food Acceptability:

Spot the Station:

Expedition 56:

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Animations (mentioned), Video (NASA), Text, Credits: NASA/Michael Johnson/Yuri Guinart-Ramirez, Lead Increment Scientist Expeditions 55 & 56.


jeudi 30 août 2018

Martian Skies Clearing over Opportunity Rover

NASA - Mars Exploration Rover B (MER-B) patch.

Aug. 30, 2018

A planet-encircling dust storm on Mars, which was first detected May 30 and halted operations for the Opportunity rover, continues to abate.

Mars Exploration Rover. Image Credits: NASA/JPL-Caltech

With clearing skies over Opportunity’s resting spot in Mars’ Perseverance Valley, engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, believe the nearly 15-year-old, solar-powered rover will soon receive enough sunlight to automatically initiate recovery procedures -- if the rover is able to do so. To prepare, the Opportunity mission team has developed a two-step plan to provide the highest probability of successfully communicating with the rover and bringing it back online.

“The Sun is breaking through the haze over Perseverance Valley, and soon there will be enough sunlight present that Opportunity should be able to recharge its batteries,” said John Callas, Opportunity project manager at JPL. “When the tau level [a measure of the amount of particulate matter in the Martian sky] dips below 1.5, we will begin a period of actively attempting to communicate with the rover by sending it commands via the antennas of NASA’s Deep Space Network. Assuming that we hear back from Opportunity, we will begin the process of discerning its status and bringing it back online.”

Image above: About 11 months before the current dust storm enveloped the rover, Opportunity took five images that were turned into a mosaic showing a view from inside the upper end of "Perseverance Valley" on the inner slope of Endeavour Crater's western rim. The images were taken on July 7, 2017. Image Credits: NASA/JPL-Caltech.

The rover’s last communication with Earth was received June 10, and Opportunity’s current health is unknown. Opportunity engineers are relying on the expertise of Mars scientists analyzing data from the Mars Color Imager (MARCI) aboard NASA’s Mars Reconnaissance Orbiter (MRO) to estimate the tau near the rover’s position.

“The dust haze produced by the Martian global dust storm of 2018 is one of the most extensive on record, but all indications are it is finally coming to a close,” said MRO Project Scientist Rich Zurek at JPL. “MARCI images of the Opportunity site have shown no active dust storms for some time within 3,000 kilometers [about 1,900 miles] of the rover site.”

With skies clearing, mission managers are hopeful the rover will attempt to call home, but they are also prepared for an extended period of silence. “If we do not hear back after 45 days, the team will be forced to conclude that the Sun-blocking dust and the Martian cold have conspired to cause some type of fault from which the rover will more than likely not recover,” said Callas. “At that point our active phase of reaching out to Opportunity will be at an end. However, in the unlikely chance that there is a large amount of dust sitting on the solar arrays that is blocking the Sun’s energy, we will continue passive listening efforts for several months.”

The additional several months for passive listening are an allowance for the possibility that a Red Planet dust devil could come along and literally dust off Opportunity’s solar arrays. Such “cleaning events” were first discovered by Mars rover teams in 2004 when, on several occasions, battery power levels aboard both Spirit and Opportunity increased by several percent during a single Martian night, when the logical expectation was that they would continue to decrease. These cleaning dust devils have even been imaged by both rovers on the surface and spacecraft in orbit (see and

Image above: Opportunity's panoramic camera (Pancam) took the component images for this view from a position outside Endeavor Crater during the span of June 7 to June 19, 2017. Toward the right side of this scene is a broad notch in the crest of the western rim of crater. Image Credits: NASA/JPL-Caltech/Cornell/Arizona State Univ.

The chances are small that dust accumulation would be the root cause of Opportunity’s lack of communication. Nonetheless, each day during the passive phase, JPL’s Radio Science group will scour the signal records taken by a very sensitive broadband receiver of radio frequencies emanating from Mars, looking for a sign that the rover is trying to reach out.

Even if the team hears back from Opportunity during either phase, there is no assurance the rover will be operational. The impact of this latest storm on Opportunity’s systems is unknown but could have resulted in reduced energy production, diminished battery performance, or other unforeseen damage that could make it difficult for the rover to fully return online.

While the situation in Perseverance Valley is critical, the rover team is cautiously optimistic, knowing that Opportunity has overcome significant challenges during its 14-plus years on Mars. The rover lost use of its front steering -- its left-front in June of 2017, and right front in 2005. Its 256-megabyte flash memory is no longer functioning. The team also knows that everything about the rover is well beyond its warranty period -- both Opportunity and its twin rover, Spirit, were constructed for 90-day missions (Spirit lasted 20 times longer and Opportunity is going on 60 times). The rovers were designed to travel about 1,000 yards, and Opportunity has logged more than 28 miles. Through thick and thin, the team has seen their rover soldier on. Now, Opportunity engineers and scientists of Opportunity are planning, and hoping, that this latest dilemma is just another bump in their Martian road.

“In a situation like this you hope for the best but plan for all eventualities,” said Callas. “We are pulling for our tenacious rover to pull her feet from the fire one more time. And if she does, we will be there to hear her.”

Updates on the dust storm and tau can be found here:

JPL, a division of Caltech in Pasadena, built Opportunity and manages the mission for NASA's Science Mission Directorate, Washington.

For more information about Opportunity, visit:

Images (mentioned), Text, Credits: NASA/JoAnna Wendel/Tony Greicius/JPL/DC Agle.

Best regards,

International Space Station Status after leak repair

ISS - Expedition 56 Mission patch.

August 30, 2018

The International Space Station’s cabin pressure is holding steady after the Expedition 56 crew conducted repair work on one of two Russian Soyuz spacecraft attached to the complex. The repair was made to address a leak that had caused a minor reduction of station pressure.

After a morning of investigations, the crew reported that the leak was isolated to a hole about two millimeters in diameter in the orbital compartment, or upper section, of the Soyuz MS-09 spacecraft attached to the Rassvet module of the Russian segment of the station.

Image above: International Space Station Configuration as of Aug. 22, 2018: Three spaceships are docked at the space station including the Progress 70 resupply ship and the Soyuz MS-08 and MS-09 crew ships. Image Credit: NASA.

Flight controllers at their respective Mission Control centers in Houston and Moscow worked together with the crew to effect a repair option in which Soyuz commander Sergey Prokopyev of Roscosmos used epoxy on a gauze wipe to plug the hole identified as the leak source. As the teams were discussing options, flight controllers in Moscow performed a partial increase of the station’s atmosphere using the ISS Progress 70 cargo ship’s oxygen supply. Flight controllers in Houston are continuing to monitor station’s cabin pressure in the wake of the repair.

Meanwhile, Roscosmos has convened a commission to conduct further analysis of the possible cause of the leak.

Throughout the day, the crew was never in any danger, and was told no further action was contemplated for the remainder of the day. Flight controllers will monitor the pressure trends overnight.

All station systems are stable and the crew is planning to return to its regular schedule of work on Friday.

Related links:

Expedition 56:

Space Station Research and Technology:

International Space Station (ISS):

Image (mentioned), Text, Credits: NASA/Mark Garcia.


Hubble observes energetic lightshow at Saturn’s north pole

ESA - Hubble Space Telescope logo.

30 August 2018

Saturn and its northern auroras (composite image)

Astronomers using the NASA/ESA Hubble Space telescope have taken a series of spectacular images featuring the fluttering auroras at the north pole of Saturn. The observations were taken in ultraviolet light and the resulting images provide astronomers with the most comprehensive picture so far of Saturn’s northern aurora.

In 2017, over a period of seven months, the NASA/ESA Hubble Space Telescope took images of auroras above Saturn’s north pole region using the Space Telescope Imaging Spectrograph. The observations were taken before and after the Saturnian northern summer solstice. These conditions provided the best achievable viewing of the northern auroral region for Hubble.

Saturn’s northern auroras

On Earth, auroras are mainly created by particles originally emitted by the Sun in the form of solar wind. When this stream of electrically charged particles gets close to our planet, it interacts with the magnetic field, which acts as a gigantic shield. While it protects Earth’s environment from solar wind particles, it can also trap a small fraction of them. Particles trapped within the magnetosphere — the region of space surrounding Earth in which charged particles are affected by its magnetic field — can be energised and then follow the magnetic field lines down to the magnetic poles. There, they interact with oxygen and nitrogen atoms in the upper layers of the atmosphere, creating the flickering, colourful lights visible in the polar regions here on Earth [1].

However, these auroras are not unique to Earth. Other planets in our Solar System have been found to have similar auroras. Among them are the four gas giants Jupiter, Saturn, Uranus and Neptune. Because the atmosphere of each of the four outer planets in the Solar System is — unlike the Earth — dominated by hydrogen, Saturn’s auroras can only be seen in ultraviolet wavelengths; a part of the electromagnetic spectrum which can only be studied from space.

Animation of Saturn’s northern auroras

Hubble allowed researchers to monitor the behaviour of the auroras at Saturn's north pole over an extended period of time. The Hubble observations were coordinated with the “Grand Finale” of the Cassini spacecraft, when the spacecraft simultaneously probed the auroral regions of Saturn [2]. The Hubble data allowed astronomers to learn more about Saturn’s magnetosphere, which is the largest of any planet in the Solar System other than Jupiter.

The images show a rich variety of emissions with highly variable localised features. The variability of the auroras is influenced by both the solar wind and the rapid rotation of Saturn, which lasts only about 11 hours. On top of this, the northern aurora displays two distinct peaks in brightness — at dawn and just before midnight. The latter peak, unreported before, seems specific to the interaction of the solar wind with the magnetosphere at Saturn’s solstice.

Closeup of Saturn's auroras

The main image presented here is a composite of observations made of Saturn in early 2018 in the optical and of the auroras on Saturn’s north pole region, made in 2017, demonstrating the size of the auroras along with the beautiful colours of Saturn.

Hubble has studied Saturn's auroras in the past. In 2004, it studied the southern auroras shortly after the southern solstice (heic0504) and in 2009 it took advantage of a rare opportunity to record Saturn when its rings were edge-on (heic1003). This allowed Hubble to observe both poles and their auroras simultaneously.


[1] The auroras here on Earth have different names depending on which pole they occur at. Aurora Borealis, or the northern lights, is the name given to auroras around the north pole and Aurora Australis, or the southern lights, is the name given for auroras around the south pole.

[2] Cassini was a collaboration between NASA, ESA and the Italian Space Agency. It spent 13 years orbiting Saturn, gathering information and giving astronomers a great insight into the inner workings of Saturn. Cassini took more risks at the end of its mission, travelling through the gap between Saturn and its rings. No spacecraft had previously done this, and Cassini gathered spectacular images of Saturn as well as new data for scientists to work with. On 15 September 2017 Cassini was sent on a controlled crash into Saturn.

More information:

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


Images of Hubble:

Study in Geophysical Research Letters:



Hubble website:

Images, Videos, Text, Credits: ESA/Hubble, NASA, A. Simon (GSFC) and the OPAL Team, J. DePasquale (STScI), L. Lamy (Observatoire de Paris).


mercredi 29 août 2018

How a NASA Scientist Looks in the Depths of the Great Red Spot to Find Water on Jupiter

NASA - JUNO Mission logo.

Aug. 29, 2018

For centuries, scientists have worked to understand the makeup of Jupiter. It’s no wonder: this mysterious planet is the biggest one in our solar system by far, and chemically, the closest relative to the Sun. Understanding Jupiter is key to learning more about how our solar system formed, and even about how other solar systems develop.

But one critical question has bedeviled astronomers for generations: Is there water deep in Jupiter's atmosphere, and if so, how much?

Gordon L. Bjoraker, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, reported in a recent paper in the Astronomical Journal that he and his team have brought the Jovian research community closer to the answer.

By looking from ground-based telescopes at wavelengths sensitive to thermal radiation leaking from the depths of Jupiter's persistent storm, the Great Red Spot, they detected the chemical signatures of water above the planet’s deepest clouds. The pressure of the water, the researchers concluded, combined with their measurements of another oxygen-bearing gas, carbon monoxide, imply that Jupiter has 2 to 9 times more oxygen than the Sun. This finding supports theoretical and computer-simulation models that have predicted abundant water (H2O) on Jupiter made of oxygen (O) tied up with molecular hydrogen (H2).

Fly into the Great Red Spot of Jupiter with NASA’s Juno Mission

Video above: This animation takes the viewer on a simulated flight into, and then out of, Jupiter’s upper atmosphere at the location of the Great Red Spot. It was created by combining an image from the JunoCam imager on NASA's Juno spacecraft with a computer-generated animation. The perspective begins about 2,000 miles (3,000 kilometers) above the cloud tops of the planet's southern hemisphere. The bar at far left indicates altitude during the quick descent; a second gauge next to that depicts the dramatic increase in temperature that occurs as the perspective dives deeper down. The clouds turn crimson as the perspective passes through the Great Red Spot. Finally, the view ascends out of the spot.Video Credits: NASA/JPL.

The revelation was stirring given that the team’s experiment could have easily failed. The Great Red Spot is full of dense clouds, which makes it hard for electromagnetic energy to escape and teach astronomers anything about the chemistry within.

“It turns out they're not so thick that they block our ability to see deeply,” said Bjoraker. “That’s been a pleasant surprise.”

New spectroscopic technology and sheer curiosity gave the team a boost in peering deep inside Jupiter, which has an atmosphere thousands of miles deep, Bjoraker said: “We thought, well, let’s just see what’s out there.”

The data Bjoraker and his team collected will supplement the information NASA’s Juno spacecraft is gathering as it circles the planet from north to south once every 53 days.

Among other things, Juno is looking for water with its own infrared spectrometer and with a microwave radiometer that can probe deeper than anyone has seen — to 100 bars, or 100 times the atmospheric pressure at Earth’s surface. (Altitude on Jupiter is measured in bars, which represent atmospheric pressure, since the planet does not have a surface, like Earth, from which to measure elevation.)

If Juno returns similar water findings, thereby backing Bjoraker’s ground-based technique, it could open a new window into solving the water problem, said Goddard’s Amy Simon, a planetary atmospheres expert.

“If it works, then maybe we can apply it elsewhere, like Saturn, Uranus or Neptune, where we don’t have a Juno,” she said.

Image above: This visualization was created from images captured by NASA’s Juno spacecraft, which has been studying Jupiter since it arrived there July 4, 2016. Image Credit: NASA/JPL/SwRI.

Juno is the latest spacecraft tasked with finding water, likely in gas form, on this giant gaseous planet.

Water is a significant and abundant molecule in our solar system. It spawned life on Earth and now lubricates many of its most essential processes, including weather. It’s a critical factor in Jupiter’s turbulent weather, too, and in determining whether the planet has a core made of rock and ice.

Jupiter is thought to be the first planet to have formed by siphoning the elements left over from the formation of the Sun as our star coalesced from an amorphous nebula into the fiery ball of gases we see today. A widely accepted theory until several decades ago was that Jupiter was identical in composition to the Sun; a ball of hydrogen with a hint of helium — all gas, no core.

But evidence is mounting that Jupiter has a core, possibly 10 times Earth’s mass. Spacecraft that previously visited the planet found chemical evidence that it formed a core of rock and water ice before it mixed with gases from the solar nebula to make its atmosphere. The way Jupiter’s gravity tugs on Juno also supports this theory. There’s even lightning and thunder on the planet, phenomena fueled by moisture.

“The moons that orbit Jupiter are mostly water ice, so the whole neighborhood has plenty of water,” said Bjoraker. “Why wouldn't the planet — which is this huge gravity well, where everything falls into it — be water rich, too?”

The water question has stumped planetary scientists; virtually every time evidence of H2O materializes, something happens to put them off the scent. A favorite example among Jupiter experts is NASA’s Galileo spacecraft, which dropped a probe into the atmosphere in 1995 that wound up in an unusually dry region. "It's like sending a probe to Earth, landing in the Mojave Desert, and concluding the Earth is dry,” pointed out Bjoraker.

In their search for water, Bjoraker and his team used radiation data collected from the summit of Maunakea in Hawaii in 2017. They relied on the most sensitive infrared telescope on Earth at the W.M. Keck Observatory, and also on a new instrument that can detect a wider range of gases at the NASA Infrared Telescope Facility.

Image above: The Great Red Spot is the dark patch in the middle of this infrared image of Jupiter. It is dark due to the thick clouds that block thermal radiation. The yellow strip denotes the portion of the Great Red Spot used in astrophysicist Gordon L. Bjoraker’s analysis. Image Credits: NASA's Goddard Space Flight Center/Gordon Bjoraker.

The idea was to analyze the light energy emitted through Jupiter’s clouds in order to identify the altitudes of its cloud layers. This would help the scientists determine temperature and other conditions that influence the types of gases that can survive in those regions.

Planetary atmosphere experts expect that there are three cloud layers on Jupiter: a lower layer made of water ice and liquid water, a middle one made of ammonia and sulfur, and an upper layer made of ammonia.

To confirm this through ground-based observations, Bjoraker’s team looked at wavelengths in the infrared range of light where most gases don’t absorb heat, allowing chemical signatures to leak out. Specifically, they analyzed the absorption patterns of a form of methane gas. Because Jupiter is too warm for methane to freeze, its abundance should not change from one place to another on the planet.

“If you see that the strength of methane lines vary from inside to outside of the Great Red Spot, it's not because there's more methane here than there,” said Bjoraker, “it's because there are thicker, deep clouds that are blocking the radiation in the Great Red Spot.”

Juno spacecraft orbiting Jupiter. Animation Credit: NASA

Bjoraker’s team found evidence for the three cloud layers in the Great Red Spot, supporting earlier models. The deepest cloud layer is at 5 bars, the team concluded, right where the temperature reaches the freezing point for water, said Bjoraker, “so I say that we very likely found a water cloud.” The location of the water cloud, plus the amount of carbon monoxide that the researchers identified on Jupiter, confirms that Jupiter is rich in oxygen and, thus, water.

Bjoraker’s technique now needs to be tested on other parts of Jupiter to get a full picture of global water abundance, and his data squared with Juno’s findings.

“Jupiter’s water abundance will tell us a lot about how the giant planet formed, but only if we can figure out how much water there is in the entire planet,” said Steven M. Levin, a Juno project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

Related links:

Astronomical Journal:

NASA’s Juno spacecraft:

Images (mentioned), Animation (mentioned), Video (mentioned), Text, Credits: NASA/Karl Hille/Goddard Space Flight Center, by Lonnie Shekhtman.


Orbital Residents Supporting Human Research and Life Support Maintenance

ISS - Expedition 56 Mission patch.

August 29, 2018

International Space Station (ISS). Image Credit: NASA

The six residents aboard the International Space Station today continued exploring how living in space impacts their bodies. The Expedition 56 crew also worked on science hardware and life support gear to ensure the orbital complex is in tip-top shape.

Three astronauts helped doctors understand what is happening to their eyes in the weightless environment of microgravity. One crew member has also worked all week on a pair of European experiments researching what happens during exercise and cognition on long-term missions in space.

Image above: Expedition 56/57 crew members (clockwise from top) Alexander Gerst, Serena Auñón-Chancellor and Sergey Prokopyev pose for a portrait inside the Bigelow Expandable Aerospace Module (BEAM). Image Credit: NASA.

NASA astronauts Ricky Arnold and Serena Auñón-Chancellor joined ESA astronaut Alexander Gerst for more regularly scheduled eye checks today. Arnold led the morning’s retina scans using optical coherence tomography on the other two crewmates. Later in the afternoon, Auñón-Chancellor and Gerst swapped medical roles and peered into each other’s eyes looking out the optic disc and macula with a fundoscope.

Gerst continued working out today in a custom t-shirt in a specialized fabric testing its comfort and thermal relief for the SpaceTex-2 study. He then moved on to the GRIP study exploring how microgravity impacts an astronaut’s cognition when working with tools and interfaces aboard spacecraft.

Image above: Flying over South Africa, seen by EarthCam on ISS, speed: 27'585 Km/h, altitude: 412,99 Km, image captured by Roland Berga (on Earth in Switzerland) from International Space Station (ISS) using ISS-HD Live application with EarthCam's from ISS on August 29, 2018 at 14:45 UTC. Image Credits: Aerospace/Roland Berga.

Commander Drew Feustel worked on the Materials Science Research Rack today replacing gear inside the refrigerator-sized device that can heat research samples to a temperature of 2500° F. Cosmonauts Oleg Artemyev and Sergey Prokopyev spent the afternoon checking the Vozdukh carbon dioxide removal device for leaks in the Russian segment of the station.

Related links:

Expedition 56:



Materials Science Research Rack:

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Text, Credits: NASA/Mark Garcia/ Aerospace/Roland Berga.

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Long-sought decay of Higgs boson observed

CERN - European Organization for Nuclear Research logo.

29 Aug 2018

Image above: An ATLAS candidate event for the Higgs boson (H) decaying to two bottom quarks (b), in association with a W boson decaying to a muon (μ) and a neutrino (ν). (Image: ATLAS/CERN).

Six years after its discovery, the Higgs boson has at last been observed decaying to fundamental particles known as bottom quarks. The finding, presented today at CERN by the ATLAS and CMS collaborations at the Large Hadron Collider (LHC), is consistent with the hypothesis that the all-pervading quantum field behind the Higgs boson also gives mass to the bottom quark. Both teams have submitted their results for publication today.

The Standard Model of particle physics predicts that about 60% of the time a Higgs boson will decay to a pair of bottom quarks, the second-heaviest of the six flavours of quarks. Testing this prediction is crucial because the result would either lend support to the Standard Model – which is built upon the idea that the Higgs field endows quarks and other fundamental particles with mass – or rock its foundations and point to new physics.

Spotting this common Higgs-boson decay channel is anything but easy, as the six-year period since the discovery of the boson has shown. The reason for the difficulty is that there are many other ways of producing bottom quarks in proton–proton collisions. This makes it hard to isolate the Higgs-boson decay signal from the background “noise” associated with such processes. By contrast, the less-common Higgs-boson decay channels that were observed at the time of discovery of the particle, such as the decay to a pair of photons, are much easier to extract from the background.

To extract the signal, the ATLAS and CMS collaborations each combined data from the first and second runs of the LHC, which involved collisions at energies of 7, 8 and 13 TeV. They then applied complex analysis methods to the data. The upshot, for both ATLAS and CMS, was the detection of the decay of the Higgs boson to a pair of bottom quarks with a significance that exceeds 5 standard deviations. Furthermore, both teams measured a rate for the decay that is consistent with the Standard Model prediction, within the current precision of the measurement.

Image above: A CMS candidate event for the Higgs boson (H) decaying to two bottom quarks (b), in association with a Z boson decaying to an electron (e-) and an antielectron (e+). (Image: CMS/CERN).

“This observationis a milestone in the exploration of the Higgs boson. It shows that the ATLAS and CMS experiments have achieved deep understanding of their data and a control of backgrounds that surpasses expectations. ATLAS has now observed all couplings of the Higgs boson to the heavy quarks and leptons of the third generation as well as all major production modes,” said Karl Jakobs, spokesperson of the ATLAS collaboration.

“Since the first single-experiment observation of the Higgs boson decay to tau-leptons one year ago, CMS, along with our colleagues in ATLAS, has observed the coupling of the Higgs boson to the heaviest fermions: the tau, the top quark, and now the bottom quark. The superb LHC performance and modern machine-learning techniques allowed us to achieve this result earlier than expected,” said Joel Butler, spokesperson of the CMS collaboration.

With more data, the collaborations will improve the precision of these and other measurements and probe the decay of the Higgs boson into a pair of much-less-massive fermions called muons, always watching for deviations in the data that could point to physics beyond the Standard Model.

“The experiments continue to home in on the Higgs particle, which is often considered a portal to new physics. These beautiful and early achievements also underscore our plans for upgrading the LHC to substantially increase the statistics. The analysis methods have now been shown to reach the precision required for exploration of the full physics landscape, including hopefully new physics that so far hides so subtly,” said CERN Director for Research and Computing Eckhard Elsen.


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.

For more information, see the ATLAS and CMS websites:



ATLAS experiment:

CMS experiment:

Standard Model of particle physics:

Higgs boson:

Large Hadron Collider (LHC):

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

Images (mentioned), Text, Credits: CERN/Ana Lopes.

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Stars v. Dust in the Carina Nebula

ESO - European Southern Observatory logo.

29 August 2018

VISTA gazes into one of the largest nebulae in the Milky Way in infrared

The Carina Nebula in infrared light

The Carina Nebula, one of the largest and brightest nebulae in the night sky, has been beautifully imaged by ESO’s VISTA telescope at the Paranal Observatory in Chile. By observing in infrared light, VISTA has peered through the hot gas and dark dust enshrouding the nebula to show us myriad stars, both newborn and in their death throes.

A wider view of the Carina Nebula

About 7500 light-years away, in the constellation of Carina, lies a nebula within which stars form and perish side-by-side. Shaped by these dramatic events, the Carina Nebula is a dynamic, evolving cloud of thinly spread interstellar gas and dust.

Digitized Sky Survey image of Eta Carinae Nebula

The massive stars in the interior of this cosmic bubble emit intense radiation that causes the surrounding gas to glow. By contrast, other regions of the nebula contain dark pillars of dust cloaking newborn stars. There’s a battle raging between stars and dust in the Carina Nebula, and the newly formed stars are winning — they produce high-energy radiation and stellar winds which evaporate and disperse the dusty stellar nurseries in which they formed.

The Carina Nebula in the constellation of Carina

Spanning over 300 light-years, the Carina Nebula is one of the Milky Way's largest star-forming regions and is easily visible to the unaided eye under dark skies. Unfortunately for those of us living in the north, it lies 60 degrees below the celestial equator, so is visible only from the Southern Hemisphere.

3D view of the Carina Nebula

Within this intriguing nebula, Eta Carinae takes pride of place as the most peculiar star system. This stellar behemoth — a curious form of stellar binary— is the most energetic star system in this region and was one of the brightest objects in the sky in the 1830s. It has since faded dramatically and is reaching the end of its life, but remains one of the most massive and luminous star systems in the Milky Way.

Zoom into the Carina Nebula

Eta Carinae can be seen in this image as part of the bright patch of light just above the point of the “V” shape made by the dust clouds. Directly to the right of Eta Carinae is the relatively small Keyhole Nebula — a small, dense cloud of cold molecules and gas within the Carina Nebula — which hosts several massive stars, and whose appearance has also changed drastically over recent centuries.

Pan across the Carina Nebula

The Carina Nebula was discovered from the Cape of Good Hope by Nicolas Louis de Lacaille in the 1750s and a huge number of images have been taken of it since then. But VISTA — the Visible and Infrared Survey Telescope for Astronomy — adds an unprecedentedly detailed view over a large area; its infrared vision is perfect for revealing the agglomerations of young stars hidden within the dusty material snaking through the Carina Nebula. In 2014, VISTA was used to pinpoint nearly five million individual sources of infrared light within this nebula, revealing the vast extent of this stellar breeding ground. VISTA is the world’s largest infrared telescope dedicated to surveys and its large mirror, wide field of view and exquisitely sensitive detectors enable astronomers [1] to unveil a completely new view of the southern sky.


[1] The Principal Investigator of the observing proposal which led to this spectacular image was Jim Emerson (School of Physics & Astronomy, Queen Mary University of London, UK). His collaborators were Simon Hodgkin and Mike Irwin (Cambridge Astronomical Survey Unit, Cambridge University, UK). The data reduction was performed by Mike Irwin and Jim Lewis (Cambridge Astronomical Survey Unit, Cambridge University, UK).

More information:

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 15 Member States: Austria, Belgium, 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 and with Australia as a strategic partner. 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 and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.


ESOcast 175 Light: Stars and Dust in the Carina Nebula:

More information about VISTA:

Photos of VISTA:

More ESO images of the Carina Nebula:

Images, Text, Credits: ESO/Garching bei München/Calum Turner/School of Physics & Astronomy, Queen Mary University of London/J. Emerson/M. Irwin/J. Lewis/Digitized Sky Survey 2. Acknowledgement: Davide De Martin/IAU and Sky & Telescope/Videos: ESO, M. Kornmesser/DSS/Risinger/Music: Johan B. Monell.

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NASA's InSight Has a Thermometer for Mars

NASA - InSight Mission logo.

August 29, 2018

Ambitious climbers, forget Mt. Everest. Dream about Mars.

Animation above: NASA's InSight Mars lander will carry a unique instrument capable of measuring heat flowing out of the planet. That could shed light on how Mars' massive mountains -- which eclipse Mt. Everest here on Earth -- first formed.Animation Credits: NASA/JPL-Caltech.

The Red Planet has some of the tallest mountains in the solar system. They include Olympus Mons, a volcano nearly three times the height of Everest. It borders a region called the Tharsis plateau, where three equally awe-inspiring volcanoes dominate the landscape.

But what geologic processes created these features on the Martian surface? Scientists have long wondered -- and may soon know more.

NASA and DLR (German Aerospace Center) plan to take the planet's temperature for the first time ever, measuring how heat flows out of the planet and drives this inspiring geology. Detecting this escaping heat will be a crucial part of a mission called InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport), managed by NASA's Jet Propulsion Laboratory in Pasadena, California.

InSight will be the first mission to study Mars' deep interior, using its Heat Flow and Physical Properties Package (HP3) instrument to measure heat as it is conducted from the interior to the planet's surface. This energy was in part captured when Mars formed more than 4 billion years ago, preserving a record of its creation. That energy is also due to the decay of radioactive elements in the rocky interior.

The way heat moves through a planet's mantle and crust determines what surface features it will have, said Sue Smrekar of JPL, the mission's deputy principal investigator and the deputy lead for HP3.

"Most of the planet's geology is a result of heat," Smrekar said. "Volcanic eruptions in the ancient past were driven by the flow of this heat, pushing up and constructing the towering mountains Mars is famous for."

Mars in a Minute: How Did Mars Get Such Enormous Mountains?

A mole for Mars

While scientists have modeled the interior structure of Mars, InSight will provide the first opportunity to find ground truth -- by literally looking below the ground.

HP3, built and operated by DLR, will be placed on the Martian surface after InSight lands on Nov. 26, 2018. A probe called a mole will pummel the ground, burying itself and dragging a tether behind it. Temperature sensors embedded in this tether will measure the natural internal heat of Mars.

That's no easy task. The mole has to burrow deep enough to escape the wide temperature swings of the Martian surface. Even the spacecraft's own "body heat" could affect HP3's super-sensitive readings.

"If the mole gets stuck higher up than expected, we can still measure the temperature variation," said HP3 investigation lead Tilman Spohn of DLR. "Our data will have more noise, but we can subtract out daily and seasonal weather variations by comparing it with ground-temperature measurements."

In addition to burrowing, the mole will give off heat pulses. Scientists will study how quickly the mole warms the surrounding rock, allowing them to figure out how well heat is conducted by the rock grains at the landing site. Densely packed grains conduct heat better -- an important piece of the equation for determining Mars' internal energy.

Cooking up a new planet

For an example of planetary heat flow, imagine a pot of water on a stove.

As water heats, it expands, becomes less dense, and rises. The cooler, denser water sinks to the bottom, where it heats up. This cycling of cool to hot is called convection. The same thing happens inside a planet, churning rock over millions of years.

Just as expanding bubbles can push off a pot lid, volcanoes are lids being blown off the top of a world. They shape a planet's surface in the process. Most of the atmosphere on rocky planets forms as volcanoes expel gas from deep below. Some of Mars' biggest dry river beds are believed to have formed when the Tharsis volcanoes spewed gas into the atmosphere. That gas contained water vapor, which cooled into liquid and may have formed the channels surrounding Tharsis.

The smaller the planet, the faster it loses its original heat. Since Mars is only one-third the size of Earth, most of its heat was lost early in its history. Most Martian geologic activity, including volcanism, occurred in the planet's first billion years.

Mars InSight, studying Mars interior. Image Credits: NASA/JPL

"We want to know what drove the early volcanism and climate change on Mars," Spohn said. "How much heat did Mars start with? How much was left to drive its volcanism?"

NASA's orbiters have given scientists a "macro" view of the planet, allowing them to study Martian geology from above. HP3will offer a first look at the inside of Mars.

"Planets are kind of like an engine, driven by heat that moves their internal parts around," Smrekar said. "With HP3, we'll be lifting the hood on Mars' engine for the first time."

What scientists learn during the InSight mission won't just apply to Mars. It will teach them how all rocky planets formed -- including Earth, its Moon and even planets in other solar systems.

JPL, a division of Caltech in Pasadena, California, manages InSight for NASA's Science Mission Directorate in Washington. InSight is part of NASA's Discovery Program, managed by the agency's Marshall Space Flight Center in Huntsville, Alabama. The InSight spacecraft, including cruise stage and lander, was built and tested by Lockheed Martin Space in Denver.

Heat Flow and Physical Properties Package (HP3):

More information about InSight is at:

Image (mentioned), Animation (mentioned), Text, Credits: NASA/JPL/Andrew Good.