lundi 16 juillet 2018

Space Station Science Highlights: Week of July 9, 2018

ISS - Expedition 56 Mission patch.

July 16, 2018

Last week, Progress, a Russian resupply spacecraft, delivered more than 5,700 pounds of crew supplies and cargo to the crew members aboard the International Space Station. Monday’s arrival of the spacecraft set a milestone for station operations by arriving with its cargo in just 3 hours and 40 minutes, or only two Earth orbits.

Image above: The Progress 43 spacecraft launched from the Baikonur Cosmodrome in Kazakhstan, headed for the International Space Station. Image Credit: NASA.

Read more details about scientific work last week aboard your orbiting laboratory:

Blood samples collected in support of JAXA investigations

Blood carries molecular signals released from cells inside the body. For the Cell-Free Epigenome (CFE) study, blood samples are collected from astronauts and cellular genes are analyzed. The results provide insight into how human bodies function during spaceflight. The Medical Proteomics investigation evaluates changes of proteins in blood serum, bone and skeletal muscles after space flight, and also supports identification of osteopenia-related proteins.

Image above: The Plant Habitat-1 compares differences in genetics, metabolism, photosynthesis, and gravity sensing between plants grown in space and on Earth. This investigation provides key insights on major changes occurring in plants exposed to microgravity. Image Credit: NASA.

By combining research results for mice, astronauts and ground patients, proteins related to osteopenia can be identified using the latest proteome analysis technique. It is anticipated that the use of the marker proteins related to osteopenia will be of benefit in the future for assessing the health of astronauts as well as osteoporosis patients on ground.

Last week, crewmembers collected blood samples in support of both investigations.

Experiment investigates protein associated with various diseases

Amyloid fibril is the protein aggregation that is known to be associated with various diseases including Alzheimer’s disease and diabetes. To develop treatments for Alzheimer's disease, it is important to clarify the mechanism of amyloid fibril formation. In the Characterization of Amyloid Formation Under Microgravity Environment: Toward Understanding the Mechanisms of Neurodegenerative Diseases (Amyloid) investigation, researchers prepare the high-quality homogeneous amyloid fibrils using the microgravity environment, and bring back the samples to characterize the fibrillation process and intermediate structure.

Image above: Mt. Rainier as seen from the vantage point of the space station. Image Credit: NASA.

Last week, crew members transferred the Amyloid samples from a -95 degree Celsius container within the Minus Eighty Degree Celsius Laboratory Freezer for ISS (MELFI) to a 2 degree Celsius container, then attached to the Cell Biology Experiment Facility (CBEF) to incubate before being placed back into MELFI.

Study examines spaceflight impact on sperm cells

The survival of multiple generations of organisms beyond the Earth requires proper function of normal sperm and eggs cells. There exists a significant knowledge gap on impacts of spaceflight conditions on the fertility-dependent functions of sperm. The goal of the Spaceflight-Altered Motility Activation and Fertility-Dependent Responses in Sperm (Micro-11) investigation is to study how sperm cells are affected by the spaceflight environment.

Image above: NASA astronaut Serena M. Auñón-Chancellor conducts Micro-11 operations in the Microgravity Science Glovebox (MSG). Image Credit: NASA.

Last week, the crew performed five runs of the Micro-11 investigation. For each run, the Micro-11 microscope was checked out, configured and calibrated before samples were fixed and loaded into the device for imaging. Finally, the samples were stored in MELFI. There will be 13 runs conducted for the Micro-11 investigation.

Other work was done on these investigations:, CEO, HDEV, Probiotics, Space Algae, HREP-HICO, HREP-RAIDS, Biomolecule Sequencer, MICS, ACE-M-2, Made in Space-Fiber Optics, Rodent Research-7, LMM Biophysics-4, Neuromapping, MagVector, MICS, Food Acceptability, MELFI, Angiex Cancer Therapy, Biochem Profile, Repository, Atomization, SAMS-II and Manufacturing Device.

Space to Ground: Same Day Delivery: 07/13/2018

Related links:

Cell-Free Epigenome (CFE):

Medical Proteomics:

Minus Eighty Degree Celsius Laboratory Freezer for ISS (MELFI):

Cell Biology Experiment Facility (CBEF):

Spaceflight-Altered Motility Activation and Fertility-Dependent Responses in Sperm (Micro-11):




Space Algae:



Biomolecule Sequencer:



Made in Space-Fiber Optics:

Rodent Research-7:

LMM Biophysics-4:




Food Acceptability:


Angiex Cancer Therapy:

Biochem Profile:




Manufacturing Device:

Expedition 56:

Spot the Station:

Space Station Research and Technology:

International Space Station (ISS):

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

Best regards,

dimanche 15 juillet 2018

Astronauts Release U.S. Spacecraft Completing Cargo Mission

Orbital ATK - Cygnus CRS-9 Mission patch.

July 15, 2018

Expedition 56 Flight Engineers Alexander Gerst of ESA (European Space Agency) and Serena Auñón-Chancellor of NASA commanded the International Space Station’s Canadarm2 robotic arm to release the Cygnus cargo spacecraft at 8:37 a.m. EDT. At the time of release, the station was flying 253 miles above the Southeastern border of Colombia. Earlier, ground controllers used the robotic arm to unberth Cygnus.

Northrop Grumman CRS-9 Cygnus departure (S.S. J.R. Thompson Cygnus)

The departing spacecraft will move a safe distance away from the space station before deploying a series of CubeSats. Cygnus will remain in orbit for two more weeks to allow a flight control team to conduct engineering tests.

Image above: The Cygnus cargo craft before its release from the Canadarm2 robotic arm. Image Credits: NASA TV/ Aerospace/Roland Berga.

Cynus is scheduled to deorbit with thousands of pounds of trash on Monday, July 30, as it burns up harmlessly over the Pacific Ocean while entering the Earth’s atmosphere. The satellite deployment and deorbit burn will not be broadcast on NASA Television.

Image above: The Cygnus cargo craft slowly departs the space station after its release from the Canadarm2 robotic arm. Image Credit: NASA TV.

The spacecraft arrived on station May 24 delivering cargo for Orbital ATK’s (now Northrop Grumman’s) ninth contracted mission under NASA’s Commercial Resupply Services contract.

Related links:

Cygnus space freighter:

Expedition 56:

Spot the Station:

Space Station Research and Technology:

International Space Station (ISS):

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

Best regards,

vendredi 13 juillet 2018

NASA Juno Data Indicate Another Possible Volcano on Jupiter Moon Io

NASA - JUNO Mission logo.

July 13, 2018

Image above: This annotated image highlights the location of the new heat source close to the south pole of Io. The image was generated from data collected on Dec. 16, 2017, by the Jovian Infrared Auroral Mapper (JIRAM) instrument aboard NASA's Juno mission when the spacecraft was about 290,000 miles (470,000 kilometers) from the Jovian moon. The scale to the right of image depicts of the range of temperatures displayed in the infrared image. Higher recorded temperatures are characterized in brighter colors – lower temperatures in darker colors. Image Credits: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM.

Data collected by NASA’s Juno spacecraft using its Jovian InfraRed Auroral Mapper (JIRAM) instrument point to a new heat source close to the south pole of Io that could indicate a previously undiscovered volcano on the small moon of Jupiter. The infrared data were collected on Dec. 16, 2017, when Juno was about 290,000 miles (470,000 kilometers) away from the moon.

“The new Io hotspot JIRAM picked up is about 200 miles (300 kilometers) from the nearest previously mapped hotspot,” said Alessandro Mura, a Juno co-investigator from the National Institute for Astrophysics in Rome. “We are not ruling out movement or modification of a previously discovered hot spot, but it is difficult to imagine one could travel such a distance and still be considered the same feature.”

Image above: This infrared image of the southern hemisphere of Jupiter’s moon Io was derived from data collected by the Jovian Infrared Auroral Mapper (JIRAM) instrument aboard NASA's Juno spacecraft on Dec. 16, 2017, when the spacecraft was about 290,000 miles (470,000 kilometers) from the Jovian moon. In this infrared image, the brighter the color the higher the temperature recorded by JIRAM. Image Credits: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM.

The Juno team will continue to evaluate data collected on the Dec. 16 flyby, as well as JIRAM data that will be collected during future (and even closer) flybys of Io. Past NASA missions of exploration that have visited the Jovian system (Voyagers 1 and 2, Galileo, Cassini and New Horizons), along with ground-based observations, have located over 150 active volcanos on Io so far. Scientists estimate that about another 250 or so are waiting to be discovered.

Juno has logged nearly 146 million miles (235 million kilometers) since entering Jupiter's orbit on July 4, 2016. Juno's 13th science pass will be on July 16.

Image above: This annotated image highlights the location of the new heat source in the southern hemisphere of the Jupiter moon Io. The image was generated from data collected on Dec. 16, 2017, by the Jovian Infrared Auroral Mapper (JIRAM) instrument aboard NASA's Juno mission when the spacecraft was about 290,000 miles (470,000 kilometers) from the Jovian moon. In this infrared image, the brighter the color the higher the temperature recorded by JIRAM. Image Credits: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM.

Juno launched on Aug. 5, 2011, from Cape Canaveral, Florida. During its mission of exploration, Juno soars low over the planet's cloud tops -- as close as about 2,100 miles (3,400 kilometers). During these flybys, Juno is probing beneath the obscuring cloud cover of Jupiter and studying its auroras to learn more about the planet's origins, structure, atmosphere and magnetosphere.

JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, for the Science Mission Directorate. The Italian Space Agency (ASI), contributed two instruments, a Ka-band frequency translator (KaT) and the Jovian Infrared Auroral Mapper (JIRAM). Lockheed Martin Space, Denver, built the spacecraft. JPL is a division of Caltech in Pasadena, California.

More information on the Juno mission is available at:

The public can follow the mission on Facebook and Twitter at:

Images (mentioned), Text, Credits: NASA/Jon Nelson/JoAnna Wendel/Southwest Research Institute/Deb Schmid/JPL/DC Agle.


Hubble and Gaia Team Up to Fuel Cosmic Conundrum

NASA - Hubble Space Telescope patch / ESA - Gaia Mission patch.

July 13, 2018

Using the power and synergy of two space telescopes, astronomers have made the most precise measurement to date of the universe’s expansion rate.

The results further fuel the mismatch between measurements for the expansion rate of the nearby universe, and those of the distant, primeval universe — before stars and galaxies even existed.

This so-called “tension” implies that there could be new physics underlying the foundations of the universe. Possibilities include the interaction strength of dark matter, dark energy being even more exotic than previously thought, or an unknown new particle in the tapestry of space.

Image above: Using two of the world’s most powerful space telescopes — NASA’s Hubble and ESA’s Gaia — astronomers have made the most precise measurements to date of the universe’s expansion rate. This is calculated by gauging the distances between nearby galaxies using special types of stars called Cepheid variables as cosmic yardsticks. By comparing their intrinsic brightness as measured by Hubble, with their apparent brightness as seen from Earth, scientists can calculate their distances. Gaia further refines this yardstick by geometrically measuring the distances to Cepheid variables within our Milky Way galaxy. This allowed astronomers to more precisely calibrate the distances to Cepheids that are seen in outside galaxies. Image Credits: NASA, ESA, and A. Feild (STScI).

Combining observations from NASA’s Hubble Space Telescope and the European Space Agency’s (ESA) Gaia space observatory, astronomers further refined the previous value for the Hubble constant, the rate at which the universe is expanding from the big bang 13.8 billion years ago.

But as the measurements have become more precise, the team’s determination of the Hubble constant has become more and more at odds with the measurements from another space observatory, ESA’s Planck mission, which is coming up with a different predicted value for the Hubble constant.

Planck mapped the primeval universe as it appeared only 360,000 years after the big bang. The entire sky is imprinted with the signature of the big bang encoded in microwaves. Planck measured the sizes of the ripples in this Cosmic Microwave Background (CMB) that were produced by slight irregularities in the big bang fireball. The fine details of these ripples encode how much dark matter and normal matter there is, the trajectory of the universe at that time, and other cosmological parameters.

These measurements, still being assessed, allow scientists to predict how the early universe would likely have evolved into the expansion rate we can measure today. However, those predictions don’t seem to match the new measurements of our nearby contemporary universe.

“With the addition of this new Gaia and Hubble Space Telescope data, we now have a serious tension with the Cosmic Microwave Background data,” said Planck team member and lead analyst George Efstathiou of the Kavli Institute for Cosmology in Cambridge, England, who was not involved with the new work.

Hubble Space Telescope (HST). Animation Credits: NASA/ESA

“The tension seems to have grown into a full-blown incompatibility between our views of the early and late time universe,” said team leader and Nobel Laureate Adam Riess of the Space Telescope Science Institute and the Johns Hopkins University in Baltimore, Maryland. “At this point, clearly it’s not simply some gross error in any one measurement. It’s as though you predicted how tall a child would become from a growth chart and then found the adult he or she became greatly exceeded the prediction. We are very perplexed.”

In 2005, Riess and members of the SHOES (Supernova H0 for the Equation of State) team set out to measure the universe’s expansion rate with unprecedented accuracy. In the following years, by refining their techniques, this team shaved down the rate measurement’s uncertainty to unprecedented levels. Now, with the power of Hubble and Gaia combined, they have reduced that uncertainty to just 2.2 percent.

Because the Hubble constant is needed to estimate the age of the universe, the long-sought answer is one of the most important numbers in cosmology. It is named after astronomer Edwin Hubble, who nearly a century ago discovered that the universe was uniformly expanding in all directions—a finding that gave birth to modern cosmology.

Galaxies appear to recede from Earth proportional to their distances, meaning that the farther away they are, the faster they appear to be moving away. This is a consequence of expanding space, and not a value of true space velocity. By measuring the value of the Hubble constant over time, astronomers can construct a picture of our cosmic evolution, infer the make-up of the universe, and uncover clues concerning its ultimate fate.

The two major methods of measuring this number give incompatible results. One method is direct, building a cosmic “distance ladder” from measurements of stars in our local universe. The other method uses the CMB to measure the trajectory of the universe shortly after the big bang and then uses physics to describe the universe and extrapolate to the present expansion rate. Together, the measurements should provide an end-to-end test of our basic understanding of the so-called “Standard Model” of the universe. However, the pieces don’t fit.

Using Hubble and newly released data from Gaia, Riess’ team measured the present rate of expansion to be 73.5 kilometers (45.6 miles) per second per megaparsec. This means that for every 3.3 million light-years farther away a galaxy is from us, it appears to be moving 73.5 kilometers per second faster. However, the Planck results predict the universe should be expanding today at only 67.0 kilometers (41.6 miles) per second per megaparsec. As the teams’ measurements have become more and more precise, the chasm between them has continued to widen, and is now about four times the size of their combined uncertainty.

Over the years, Riess’ team has refined the Hubble constant value by streamlining and strengthening the “cosmic distance ladder,” used to measure precise distances to nearby and far-off galaxies. They compared those distances with the expansion of space, measured by the stretching of light from nearby galaxies. Using the apparent outward velocity at each distance, they then calculated the Hubble constant.

To gauge the distances between nearby galaxies, his team used a special type of star as cosmic yardsticks or milepost markers. These pulsating stars, called Cephied variables, brighten and dim at rates that correspond to their intrinsic brightness. By comparing their intrinsic brightness with their apparent brightness as seen from Earth, scientists can calculate their distances.

Artist's view of Gaia spacecraft. Image Credit: ESA

Gaia further refined this yardstick by geometrically measuring the distance to 50 Cepheid variables in the Milky Way. These measurements were combined with precise measurements of their brightnesses from Hubble. This allowed the astronomers to more accurately calibrate the Cepheids and then use those seen outside the Milky Way as milepost markers.

“When you use Cepheids, you need both distance and brightness,” explained Riess. Hubble provided the information on brightness, and Gaia provided the parallax information needed to accurately determine the distances. Parallax is the apparent change in an object’s position due to a shift in the observer’s point of view. Ancient Greeks first used this technique to measure the distance from Earth to the Moon.

“Hubble is really amazing as a general-purpose observatory, but Gaia is the new gold standard for calibrating distance. It is purpose-built for measuring parallax—this is what it was designed to do,” Stefano Casertano of the Space Telescope Science Institute and a member of the SHOES team added. “Gaia brings a new ability to recalibrate all past distance measures, and it seems to confirm our previous work. We get the same answer for the Hubble constant if we replace all previous calibrations of the distance ladder with just the Gaia parallaxes. It’s a crosscheck between two very powerful and precise observatories.”

The goal of Riess’ team is to work with Gaia to cross the threshold of refining the Hubble constant to a value of only one percent by the early 2020s. Meanwhile, astrophysicists will likely continue to grapple with revisiting their ideas about the physics of the early universe.

The Riess team's latest results are published in the July 12 issue of the Astrophysical Journal:

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.

Hubble Space Telescope (HST):

ESA's Gaia:

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Karl Hille/Space Telescope Science Institute/Ann Jenkins/Ray Villard/Adam Riess.

Best regards,

Jamming with the 'Spiders' from Mars

NASA - Mars Reconnaissance Orbiter (MRO) logo.

July 13, 2018

This image from NASA's Mars Reconnaissance Orbiter, acquired May 13, 2018 during winter at the South Pole of Mars, shows a carbon dioxide ice cap covering the region and as the sun returns in the spring, "spiders" begin to emerge from the landscape.

But these aren't actual spiders. Called "araneiform terrain," describes the spider-like radiating mounds that form when carbon dioxide ice below the surface heats up and releases. This is an active seasonal process not seen on Earth. Like dry ice on Earth, the carbon dioxide ice on Mars sublimates as it warms (changes from solid to gas) and the gas becomes trapped below the surface.

Over time the trapped carbon dioxide gas builds in pressure and is eventually strong enough to break through the ice as a jet that erupts dust. The gas is released into the atmosphere and darker dust may be deposited around the vent or transported by winds to produce streaks. The loss of the sublimated carbon dioxide leaves behind these spider-like features etched into the surface.

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.

Mars Reconnaissance Orbiter (MRO):

Image, Text, Credits: NASA/Tony Greicius/JPL-Caltech/Univ. of Arizona.


"Pleasure" flights in the space planned from 2019

Virgin Galactic logo / Blue Origin logo.

July 13, 2018

Pioneering companies in the field of space tourism claim to be able to offer flights in just a few months. Virgin Galactic and Blue Origin are racing to be the first to finish the tests.

SpaceShipTwo VSS Unity attached under a carrier plane, WhiteKnightTwo

The two most advanced private companies in the space tourism market say they are only a few months away from their first flights into space with customers on board, although each remains cautious and refrains from advancing a specific date.

Blue Origin New Shepard rocket launch

Virgin Galactic, founded by British billionaire Richard Branson, and Blue Origin, by the more discreet billionaire Jeff Bezos, boss of Amazon, are racing to be the first to finish the tests. Both companies have radically different technologies.

Few minutes of weightlessness

For both, the passengers will not go into orbit around the Earth: their experience in weightlessness will only last a few minutes, unlike the few space tourists who paid tens of millions of dollars to travel aboard a Soyuz and of the International Space Station (ISS) in the 2000s.

For a ticket much cheaper (250 000 dollars at Virgin, an amount unknown at Blue Origin), these new tourists will be propelled to several tens of kilometers, before falling back to Earth. By comparison, the ISS is in orbit at 400 km.

The goal is to approach or exceed the imaginary line marking the beginning of space, the Karman line, 100 km, or the line preferred by the US military, 50 miles (80 km). At this altitude, the sky becomes darker, and the curvature of the Earth appears clearly.

Virgin Galactic

At Virgin Galactic, six passengers and two pilots will set up aboard the SpaceShipTwo VSS Unity, which looks like a private jet. The VSS Unity will be attached under a carrier plane, dubbed WhiteKnightTwo. Once dropped at an altitude of 15,000 meters, the ship will light its rocket towards the sky. There passengers will float in weightlessness for several minutes.

The descent will be slowed down by a system of "empennage": the fins of the tail of the ship will pivot and the ship will arch before returning to normal. Then the aircraft will land on an airstrip from Virgin's "spaceport" in the New Mexico desert.

SpaceShipTwo VSS Unity

In a May 29 test in the Mojave desert, the ship reached an altitude of 35 km. In October 2014, Virgin's ship crashed into flight due to a pilot error, killing one of the two pilots. The tests resumed with a new device.

Virgin has reached an agreement to open a second spaceport in Italy, at Taranto-Grottaglie airport. Richard Branson said in May, on BBC Radio 4, he hoped to be one of the first passengers in the next 12 months. About 650 customers are on the waiting list, says Virgin to AFP.

Blue Origin

Blue Origin has developed a system that resembles traditional rockets: the New Shepard. Six passengers will sit in the seats of a "capsule", a cabin attached to the top of a vertical rocket 18 meters in height. After the launch, which will propel the capsule to near Mach 3, it will detach and continue its trajectory a few kilometers to the sky. In a test on April 29, the capsule reached 107 km. During this time, the rocket will come down again ... and will land, slowly, vertically.

Blue Origin Crew Capsule

After several minutes of weightlessness, during which passengers can get up and look out through large portholes, the capsule will fall back to Earth, slowed by three large parachutes and retrofuses. From take-off to landing, the flight of the last test lasted 10 minutes.

So far only manikin testing has been done on the Blue Origin site in Texas. But a leader, Rob Meyerson, said in June that the first inhabited tests would take place "soon". Another official, Yu Matsutomi, said Wednesday at a conference that they would be held "at the end of this year," according to Space News.

And after?

SpaceX and Boeing are developing capsules to transport NASA astronauts, probably from 2020 as a result of delays. Considerable investments that these companies will probably seek to amortize by offering trips to individuals.

Boeing and SpaceX Crew Vehicles

"If you want to go into space, you'll soon have four times more options than you've ever had," says AFP Phil Larson, deputy dean of the School of Engineering of the United States. University of Colorado at Boulder.

In the longer term, the Russian company building the Soyuz is studying the possibility of bringing tourists back to the ISS. And an American start-up, Orion Span, has announced this year to place a space station in orbit in a few years, but this project is still very far from the day.

Related links:

Virgin Galactic:

Blue Origin:

Images, Text, Credits: Virgin Galactic/Blue Origin/Boeing/SpaceX/AFP/ Aerospace/Roland Berga.

Best regards,

jeudi 12 juillet 2018

Multi-messenger astronomy

ESA - INTEGRAL Mission patch.

12 July 2018

An international team of scientists has found first evidence of a source of high-energy neutrinos: a flaring active galaxy, or blazar, 4 billion light years from Earth. Following a detection by the IceCube Neutrino Observatory on 22 September 2017, ESA's INTEGRAL satellite joined a collaboration of observatories in space and on the ground that kept an eye on the neutrino source, heralding the thrilling future of multi-messenger astronomy.

Neutrinos are nearly massless, ‘ghostly’ particles that travel essentially unhindered through space at close to the speed of light [1]. Despite being some of the most abundant particles in the Universe – 100 000 billion pass through our bodies every second – these electrically neutral, subatomic particles are notoriously difficult to detect because they interact with matter incredibly rarely.

Image above: Artist's impression of blazar neutrinos and gamma rays reaching Earth. Image Credits: IceCube/NASA.

While primordial neutrinos were created during the Big Bang, more of these elusive particles are routinely produced in nuclear reactions across the cosmos. The majority of neutrinos arriving at Earth derive from the Sun, but those that reach us with the highest energies are thought to stem from the same sources as cosmic rays – highly energetic particles originating from exotic sources outside the Solar System.

Unlike neutrinos, cosmic rays are charged particles and so their path is bent by magnetic fields, even weak ones. The neutral charge of neutrinos instead means they are unaffected by magnetic fields, and because they pass almost entirely through matter they can be used to trace a straight path all the way back to their source.

Acting as ‘messengers’, neutrinos directly carry astronomical information from the far reaches of the Universe. Over the past decades, several instruments have been built on Earth and in space to decode their messages, though detecting these particles is no easy feat. In particular, the source of high-energy neutrinos has, until now, remained unproven.

On 22 September 2017, one of these high-energy neutrinos arrived at the IceCube Neutrino Observatory at the South Pole [2]. The event was named IceCube-170922A.

The IceCube observatory, which encompasses a cubic kilometre of deep, pristine ice, detects neutrinos through their secondary particles, muons. These muons are produced on the rare occasion that a neutrino interacts with matter in the vicinity of the detector, and they create tracks, kilometres in length, as they pass through layers of Antarctic ice. Their long paths mean their position can be well defined, and the source of the parent neutrino can be pinned down in the sky.

During the 22 September event, a traversing muon deposited 22 TeV of energy in the IceCube detector. From this, scientists estimated the energy of the parent neutrino to be around 290 TeV, indicating a 50 percent chance that it had an astrophysical origin beyond the Solar System.

Image above: Neutrino detection at the IceCube observatory. Image Credits: IceCube Collaboration/NSF.

When the origin of a neutrino cannot be robustly identified by IceCube, like in this case, multi-wavelength observations are required to investigate its source. So, following the detection, IceCube scientists circulated the coordinates in the sky of the neutrino’s origin, inferred from their observations, to a worldwide network of ground and space-based observatories working across the full electromagnetic spectrum.

These included NASA's Fermi gamma-ray space telescope and the Major Atmospheric Gamma-Ray Imaging Cherenkov (MAGIC) on La Palma, in the Canary Islands, which looked to this portion of the sky and found the known blazar, TXS 0506+056, in a ‘flaring’ state – a period of intense high-energy emission – at the same time the neutrino was detected at the South Pole.

Blazars are the central cores of giant galaxies that host an actively accreting supermassive black-hole at their heart, where matter spiralling in forms a hot, rotating disc that generates enormous amounts of energy, along with a pair of relativistic jets.

These jets are colossal columns that funnel radiation, photons and particles – including neutrinos and cosmic rays – tens of light years away from the central black hole at speeds very close to the speed of light. A specific feature of blazars is that one of these jets happens to point towards Earth, making its emission appear exceptionally bright.

Scientists around the world began observing this blazar – the likely source of the neutrino detected by IceCube – in a variety of wavelengths, from radio waves to high-energy gamma rays. ESA's INTEGRAL gamma-ray observatory was part of this international collaboration [3].

“This is a very important milestone to understanding how high-energy neutrinos are produced,” says Carlo Ferrigno from the INTEGRAL Science Data Centre at the University of Geneva, Switzerland.

“There have been previous claims that blazar flares were associated with the production of neutrinos, but this, the first confirmation, is absolutely fundamental. This is an exciting period for astrophysics,” he adds.

INTEGRAL, which surveys the sky in hard X-rays and soft gamma rays, is also sensitive to transient high-energy sources across the whole sky. At the time the neutrino was detected, it did not record any burst of gamma rays from the location of the blazar, so scientists were able to rule out prompt emissions from certain sources, such as a gamma-ray burst.

Image above: Artist's impression of INTEGRAL. Image Credit: ESA.

After the neutrino alert from IceCube, INTEGRAL pointed to this area of the sky on various occasions between 30 September and 24 October 2017 with its wide-field instruments, and it did not observe the blazar to be in a flaring state in the hard X-ray or soft gamma-ray range.

The fact that INTEGRAL could not detect the source in the follow-up observations provided significant information about this blazar, allowing scientists to place a useful upper limit on its energy output during this period.

“INTEGRAL was important in constraining the properties of this blazar, but also in allowing scientists to exclude other neutrino sources such as gamma-ray bursts,” explains Volodymyr Savchenko from the INTEGRAL Science Data Centre, who led the analysis of the INTEGRAL data.

With facilities spread across the globe and in space, scientists now have the capability to detect a plethora of 'cosmic messengers' travelling vast distances at extremely high speeds, in the form of light, neutrinos, cosmic rays, and even gravitational waves.

“The ability to globally marshal telescopes to make a discovery using a variety of wavelengths in cooperation with a neutrino detector like IceCube marks a milestone in what scientists call multi-messenger astronomy,” says Francis Halzen from the University of Wisconsin–Madison, USA, lead scientist for the IceCube Neutrino Observatory.

By combining the information gathered by each of these sophisticated instruments to investigate a wide range of cosmic processes, the era of multi-messenger astronomy has truly entered the phase of scientific exploitation.

ESA’s high-energy space telescopes are fully integrated into this network of large multi-messenger collaborations, as demonstrated during the recent detection of gravitational waves with a corresponding gamma-ray burst – the latter detected by INTEGRAL – released by the collision of two neutron stars, and in the subsequent follow-up campaign, with contributions by INTEGRAL as well as the XMM-Newton X-ray observatory.

Pooling resources from these and other observatories is key for the future of astrophysics, fostering our ability to decode the messages that reach us from across the Universe.

“INTEGRAL is the only observatory available in the hard X-ray and soft gamma-ray domain that has the ability to perform dedicated imaging and spectroscopy, as well as having an instantaneous all-sky view at any time,” notes Erik Kuulkers, INTEGRAL project scientist at ESA.

“After more than 15 years of operations, INTEGRAL is still at the forefront of high-energy astrophysics.”


[1] Described by Frederick Reines, one of the scientists who made the first neutrino detection, as “... the most tiny quantity of reality ever imagined by a human being,” one neutrino is estimated to contain one millionth of the mass of an electron.

[2] The IceCube Collaboration is funded primarily by the National Science Foundation and is operated by a team headquartered at the University of Wisconsin–Madison, USA. The research efforts, including critical contributions to the detector operation, are supported by funding agencies in Australia, Belgium, Canada, Denmark, Germany, Japan, New Zealand, Republic of Korea, Sweden, Switzerland, the United Kingdom, and the USA.

[3] These results are detailed in the paper “Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A” by The IceCube, Fermi-LAT, MAGIC, AGILE, ASAS-SN, HAWC, H.E.S.S, INTEGRAL, Kanata, Kiso, Kapteyn, Liverpool telescope, Subaru, Swift/NuSTAR, VERITAS, and VLA/17B-403 teams, published in Science:

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Images (mentioned), Text, Credits: ESA/Markus Bauer/Erik Kuulkers/INTEGRAL Science Data Centre/University of Geneva/Volodymyr Savchenko/Carlo Ferrigno/IceCube/University of Wisconsin–Madison/Francis Halzen/Sílvia Bravo Gallart.