samedi 2 février 2019

Hubble Spies Stellar Time Capsule with Cosmic Distance Markers

NASA - Hubble Space Telescope patch.

Feb. 2, 2019

This image from the NASA/ESA Hubble Space Telescope reveals an ancient, glimmering ball of stars called NGC 1466. It is a globular cluster — a gathering of stars all held together by gravity — that is slowly moving through space on the outskirts of the Large Magellanic Cloud, one of our closest galactic neighbors.

NGC 1466 certainly is one for extremes. It has a mass equivalent to roughly 140,000 Suns and an age of around 13.1 billion years, making it almost as old as the universe itself. This fossil-like relic from the early universe lies some 160,000 light-years away from us.

Nestled within this ancient time capsule are 49 known RR Lyrae variable stars, which are indispensable tools for measuring distances in the universe. These variable stars have well-defined luminosities, meaning that astronomers know the total amount of energy they emit. By comparing this known luminosity to how bright the stars appear in the sky, the distance to these stars can be easily calculated. Astronomical objects such as this are known as standard candles, and are fundamental to the so-called cosmic distance ladder.

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

For more information about Hubble, visit:

Animation (mentioned), Image, Credits: ESA/Hubble & NASA/Text credit: European Space Agency (ESA)/NASA/Karl Hille.


vendredi 1 février 2019

Crew Wraps Up Biomedical Studies; Films Station in Virtual Reality

ISS - Expedition 58 Mission patch.

February 1, 2019

A pair of biomedical experiments are wrapping up today aboard the International Space Station as the Expedition 58 crew began its weekend. The orbital residents are also filming a virtual reality (VR) experience and working on plumbing and life support hardware.

Image above: Astronaut Anne McClain is pictured wearing a sensor on her forehead that is collecting data to determine how an astronaut’s “biological clock” changes during long-duration spaceflight. Image Credit: NASA.

Anne McClain of NASA removed sensors from her head and chest this morning that collected data about her circadian rhythm, or “biological clock,” and how it is adapting off Earth. Canadian Space Agency astronaut David Saint-Jacques stowed the wearable Bio-Monitor hardware that monitors an astronaut’s vital signs during normal activities with minimum interference.

McClain then set up a VR camera to film a first-person’s view aboard the orbital lab in an immersive, cinematic experience. She finished the workday with Saint-Jacques on orbital plumbing work in the Tranquility module.

International Space Station (ISS) flying over the Earth. Animation Credit: NASA

The Combustion Integrated Rack received more attention today as Saint-Jacques replaced hardware in the fuel and flame research platform. He also assisted McClain with the VR camera installation, set up audio equipment and filmed an introduction.

Commander Oleg Kononenko also up video gear today in Japan’s Kibo lab module and held a conference with Russian students and educators. The veteran cosmonaut then spent part of the afternoon conducting maintenance on life support equipment in the station’s Russian segment.

Related links:

Expedition 58:

Circadian rhythm:


VR camera:

Tranquility module:

Combustion Integrated Rack:

Kibo lab module:

Space Station Research and Technology:

International Space Station (ISS):

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

Best regards,

'Mars Buggy' Curiosity Measures a Mountain's Gravity

NASA - Mars Science Laboratory (MSL) patch.

Feb. 1, 2019

Apollo 17 astronauts drove a moon buggy across the lunar surface in 1972, measuring gravity with a special instrument. There are no astronauts on Mars, but a group of clever researchers realized they have just the tools for similar experiments with the Martian buggy they're operating.

Animation above: Side-by-side images depict NASA's Curiosity rover (illustration at left) and a moon buggy driven during the Apollo 16 mission. Animation Credits: NASA/JPL-Caltech.

In a new paper in Science, the researchers detail how they repurposed sensors used to drive the Curiosity rover and turned them into gravimeters, which measure changes in gravitational pull. That enabled them to measure the subtle tug from rock layers on lower Mount Sharp, which rises 3 miles (5 kilometers) from the base of Gale Crater and which Curiosity has been climbing since 2014. The results? It turns out the density of those rock layers is much lower than expected.

Just like a smartphone, Curiosity carries accelerometers and gyroscopes. Moving your smartphone allows these sensors to determine its location and which way it's facing. Curiosity's sensors do the same thing but with far more precision, playing a crucial role in navigating the Martian surface on each drive. Knowing the rover's orientation also lets engineers accurately point its instruments and multidirectional, high-gain antenna.

Image above: A selfie taken by NASA's Curiosity Mars rover on Sol 2291 (January 15) at the "Rock Hall" drill site, located on Vera Rubin Ridge. Image Credits: NASA/JPL-Caltech/MSSS.

By happy coincidence, the rover's accelerometers can be used like Apollo 17's gravimeter. The accelerometers detect the gravity of the planet whenever the rover stands still. Using engineering data from the first five years of the mission, the paper's authors measured the gravitational tug of Mars on the rover. As Curiosity ascends Mount Sharp, the mountain adds additional gravity - but not as much as scientists expected.

"The lower levels of Mount Sharp are surprisingly porous," said lead author Kevin Lewis of Johns Hopkins University. "We know the bottom layers of the mountain were buried over time. That compacts them, making them denser. But this finding suggests they weren't buried by as much material as we thought."

Science from a Mars Buggy

The Apollo 17 astronauts drove their buggy across the Moon's Taurus-Littrow Valley, periodically stopping to capture 25 measurements. Lewis has studied Martian gravity fields using data collected by NASA's orbiters and was familiar with Apollo 17's gravimeter.

Apollo 17 Lunar Roving Vehicle. Image Credit: NASA

The Science paper uses over 700 measurements from Curiosity's accelerometers, taken between October 2012 and June 2017. These data were calibrated to filter out "noise," such as the effects of temperature and the tilt of the rover during its climb. The calculations were then compared to models of Mars' gravity fields to ensure accuracy.

The results were also compared to mineral-density estimates from Curiosity's Chemistry and Mineralogy instrument, which characterizes the crystalline minerals in rock samples by using an X-ray beam. That data helped inform how porous the rocks are.

Mountain of Mystery

There are many mountains within craters or canyons on Mars, but few approach the scale of Mount Sharp. Scientists still aren't sure how the mountain grew inside of Gale Crater. One idea is that the crater was once filled with sediment. How much of it was filled remains a source of debate, but the thinking is that many millions of years of wind and erosion eventually excavated the mountain.

If the crater had been filled to the brim, all that material should have pressed down, or compacted, the many layers of fine-grained sediment beneath it. But the new paper suggests Mount Sharp's lower layers have been compacted by only a half-mile to a mile (1 to 2 kilometers) - much less than if the crater had been completely filled.

"There are still many questions about how Mount Sharp developed, but this paper adds an important piece to the puzzle," said study co-author Ashwin Vasavada, Curiosity's project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. JPL manages the Mars Science Laboratory mission that Curiosity is a part of. "I'm thrilled that creative scientists and engineers are still finding innovative ways to make new scientific discoveries with the rover," he added.

Lewis said that Mars holds plenty of mystery beyond Mount Sharp. Its landscape is like Earth's, but sculpted more by wind and blowing sand than by water. They're planetary siblings, at once familiar and starkly different.

"To me, Mars is the uncanny valley of Earth," Lewis said. "It's similar but was shaped by different processes. It feels so unnatural to our terrestrial experience."

For more about Curiosity, visit:

For more about NASA's Mars program, visit:

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


jeudi 31 janvier 2019

NASA's AIRS Captures Polar Vortex Moving in Over US

NASA & JPL - AIRS Mission patch.

Jan. 31, 2019

Animation above: NASA's Atmospheric Infrared Sounder (AIRS) instrument captures a polar vortex moving from Central Canada into the U.S. Midwest from January 20 through January 29. Animation Credits: NASA/JPL-Caltech AIRS Project.

The U.S. Midwest has been gripped by the lowest temperatures it has seen in years. An unusually cold Arctic air mass, called a polar vortex, is responsible for the severe temperatures, which in many areas have plunged well below 0 degrees Fahrenheit (-18 degrees Celsius).

NASA's Atmospheric Infrared Sounder (AIRS) instrument aboard the Aqua satellite captured the polar vortex as it moved southward from central Canada into the U.S. Midwest from Jan. 20 through Jan. 29. The lowest temperatures are shown in purple and blue and range from -40 degrees Fahrenheit (also -40 degrees Celsius) to -10 degrees Fahrenheit (-23 degrees Celsius). As the data series progresses, you can see how the coldest purple areas of the air mass scoop down into the U.S.

Aqua satellite. Image Credit: NASA

The polar vortex is responsible for a number of deaths, disruptions to services, and energy outages in the affected areas.

AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), senses emitted infrared and microwave radiation from Earth to provide a three-dimensional look at Earth's weather and climate. Working in tandem, the two instruments make simultaneous observations down to Earth's surface. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, three-dimensional map of atmospheric temperature and humidity, cloud amounts and heights, greenhouse gas concentrations and many other atmospheric phenomena.

Video above: The Advanced Microwave Sounding Unit (AMSU-A), a 15-channel microwave sounder designed primarily to obtain temperature profiles in the upper atmosphere (especially the stratosphere) and to provide a cloud-filtering capability for tropospheric temperature observations. The first AMSU was launched in May 1998 on board the National Oceanic and Atmospheric Administration's (NOAA's) NOAA 15 satellite. The EOS AMSU-A is part of a closely coupled triplet of instruments that include the AIRS and HSB.

Launched into Earth orbit in 2002, the AIRS and AMSU instruments are managed by NASA's Jet Propulsion Laboratory in Pasadena, California, under contract to NASA. JPL is a division of the Caltech in Pasadena.

Related article:

Warming Seas May Increase Frequency of Extreme Storms

More information about AIRS can be found at:

Atmospheric Infrared Sounder (AIRS):


NASA Aqua satellite:

Animation (mentioned), Image (mentioned), Video, Text, Credits: NASA/Tony Greicius/JPL/Esprit Smith.


Fiery Research Work and CubeSats Deployed Today

ISS - Expedition 58 Mission patch.

January 31, 2019

The Expedition 58 crew set up a variety of combustion research hardware today to look at what happens to high temperatures, fuels and flames in space. The International Space Station also deployed the first set of CubeSats this year.

Image above: The Expedition 58 crew gathers inside the Zvezda service module for a portrait. From left are, NASA astronaut Anne McClain, Roscosmos cosmonaut Oleg Kononenko and Canadian Space Agency astronaut David Saint-Jacques. Image Credit: NASA.

The Two-Phase Flow Experiment, sponsored by the Japan Aerospace Exploration Agency, investigates the heat transfer caused by boiling liquids in space. Flight Engineer Anne McClain set up a specialized microscope to study the phenomena inside Japan’s Kibo lab module today. Results may inform future designs of high-performance thermal management and cooling systems on Earth and in space.

Flight Engineer David Saint-Jacques opened the Combustion Integrated Rack inside the U.S. Destiny lab module again today for more maintenance work. The Canadian astronaut replaced a control unit and a radiometer inside the fuel and flame research device.

The duo also monitored and photographed several CubeSats deployed into Earth orbit outside Kibo’s airlock today. The CubeSats are inexpensive tiny research satellites that will explore Earth’s ionosphere and study space communication techniques.

Image above: Flyingt over Brazil, seen by EarthCam on ISS, speed: 27'614 Km/h, altitude: 405,37 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 January 31, 2019 at 18:53 UTC. Image Credits: Aerospace/Roland Berga.

Commander Oleg Kononenko, the four-time space station resident from Roscosmos, started Thursday photographing the interior portion of the orbital lab’s Russian segment. The veteran cosmonaut then moved onto life support maintenance and explored ways students and educators can collaborate with space crews.

Related links:

Expedition 58:

Two-Phase Flow Experiment:

Kibo lab module:

Destiny lab module:


Russian segment:

Collaborate with space crews:

Space Station Research and Technology:

International Space Station (ISS):

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

Best regards,

Hubble fortuitously discovers a new galaxy in the cosmic neighbourhood

ESA - Hubble Space Telescope logo.

31 January 2019

The accidentally discovered galaxy Bedin I

Astronomers using the NASA/ESA Hubble Space Telescope to study some of the oldest and faintest stars in the globular cluster NGC 6752 have made an unexpected finding. They discovered a dwarf galaxy in our cosmic backyard, only 30 million light-years away. The finding is reported in the journal Monthly Notices of the Royal Astronomical Society: Letters.

Bedin 1 in NGC 6752

An international team of astronomers recently used the NASA/ESA Hubble Space Telescope to study white dwarf stars within the globular cluster NGC 6752. The aim of their observations was to use these stars to measure the age of the globular cluster, but in the process they made an unexpected discovery.

Globular cluster NGC 6752

In the outer fringes of the area observed with Hubble’s Advanced Camera for Surveys a compact collection of stars was visible. After a careful analysis of their brightnesses and temperatures, the astronomers concluded that these stars did not belong to the cluster — which is part of the Milky Way — but rather they are millions of light-years more distant.

Wide-field view of NGC 6752 (ground-based view)

Our newly discovered cosmic neighbour, nicknamed Bedin 1 by the astronomers, is a modestly sized, elongated galaxy. It measures only around 3000 light-years at its greatest extent — a fraction of the size of the Milky Way. Not only is it tiny, but it is also incredibly faint. These properties led astronomers to classify it as a dwarf spheroidal galaxy.

Zooming in on NGC 6752 and Bedin 1

Dwarf spheroidal galaxies are defined by their small size, low-luminosity, lack of dust and old stellar populations [1]. 36 galaxies of this type are already known to exist in the Local Group of Galaxies, 22 of which are satellite galaxies of the Milky Way.

While dwarf spheroidal galaxies are not uncommon, Bedin 1 has some notable features. Not only is it one of just a few dwarf spheroidals that have a well established distance but it is also extremely isolated. It lies about 30 million light-years from the Milky Way and 2 million light-years from the nearest plausible large galaxy host, NGC 6744. This makes it possibly the most isolated small dwarf galaxy discovered to date.

Flight to Bedin 1

From the properties of its stars, astronomers were able to infer that the galaxy is around 13 billion years old — nearly as old as the Universe itself. Because of its isolation — which resulted in hardly any interaction with other galaxies — and its age, Bedin 1 is the astronomical equivalent of a living fossil from the early Universe.

The discovery of Bedin 1 was a truly serendipitous find. Very few Hubble images allow such faint objects to be seen, and they cover only a small area of the sky. Future telescopes with a large field of view, such as the WFIRST telescope, will have cameras covering a much larger area of the sky and may find many more of these galactic neighbours.

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


[1] While similar to dwarf elliptical galaxies in appearance and properties, dwarf spheroidal galaxies are in general approximately spherical in shape and have a lower luminosity.

More information:

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

The results were presented in the letter The HST Large Programme on NGC 6752. I. Serendipitous discovery of a dwarf galaxy in background, published in the journal Monthly Notices of the Royal Astronomical Society: Letters.

The international team of astronomers that carried out this study consists of L. R. Bedin (INAF-Osservatorio Astronomico di Padova, Italy), M. Salaris (Liverpool John Moores University, UK), R. M. Rich (University of California Los Angeles, USA), H. Richer (University of British Columbia), J. Anderson (Space Telescope Science Institute, USA), B. Bettoni (INAF-Osservatorio Astronomico di Padova, Italy), D. Nardiello (Università di Padova, Italy), A. P. Milone (Università di Padova, Italy), A. F. Marino (Università di Padova, Italy), M. Libralato (Space Telescope Science Institute, USA), A. Bellini (Space Telescope Science Institute, USA), A. Dieball (University of Bonn, Germany), P. Bergeron (Université de Montréal, Canada), A. J. Burgasser (University of California San Diego, USA), D. Apai (University of Arizona, USA)


Images of Hubble:

Hubblesite release:

Science paper:

NASA/ESA Hubble Space Telescope:

Images, Text,  Credits: NASA/ESA, Bedin et al./Mathias Jäger/Hubble, NASA, Bedin et al., Digitized Sky Survey 2/Acknowledgement: Davide De Martin/Videos: Credits: Risinger, DSS, Hubble, Damian Peach/Music: Astral Electronic/SA/Hubble, M. Kornmesser.


mercredi 30 janvier 2019

Crew Works CubeSats, Life Science and Configures Physics Hardware

ISS - Expedition 58 Mission patch.

January 30, 2019

The International Space Station is set to deploy a new series of CubeSats as the Expedition 58 crew configures research hardware to enable a variety of space experiments.

Japan’s Kibo laboratory module airlock has been set up with a small satellite deployer loaded with several CubeSats. Astronaut Anne McClain finished the installation work Wednesday, depressurized the airlock and maneuvered the deployer outside Kibo.

Image above: Portions of Cuba, The Bahamas and the Turks and Caicos Islands are viewed from the International Space Station as the orbital complex flew 252 miles above the Atlantic Ocean. At left, is the aft end of the Progress 70 resupply ship from Russia attached to the Pirs docking compartment. Image Credit: NASA.

She and fellow astronaut David Saint-Jacques will monitor and photograph the CubeSat deployments planned for Thursday around noon EST. The CubeSats will study Earth’s ionosphere and satellite communication techniques.

McClain next inventoried Rodent Research gear trashing some hardware to make extra space aboard the lab. She later swapped a hard drive on a laptop computer dedicated to meteor observations then attached sensors to her head and chest for the Circadian Rhythms study.

International Space Station (ISS). Animation Credit: NASA

Saint-Jacques installed new electronics on the Kubik incubator upgrading the device that houses biology experiments on seeds, cells and small animals. He later swapped parts in the Combustion Integrated Rack that permits safe research into fuel and flames aboard the orbital lab.

Commander Oleg Kononenko started Wednesday researching microgravity’s effect on heart rate and breathing. He later explored advanced photography tools and techniques to better detect targets of interest on Earth.

Related links:

Expedition 58:

Kibo laboratory module:


Rodent Research:


Circadian Rhythms:


Advanced photography tools and techniques:

Space Station Research and Technology:

International Space Station (ISS):

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

Best regards,

Huge Cavity in Antarctic Glacier Signals Rapid Decay

NASA - Operation IceBridge Mission patch.

January 30, 2019

A gigantic cavity - two-thirds the area of Manhattan and almost 1,000 feet (300 meters) tall - growing at the bottom of Thwaites Glacier in West Antarctica is one of several disturbing discoveries reported in a new NASA-led study of the disintegrating glacier. The findings highlight the need for detailed observations of Antarctic glaciers' undersides in calculating how fast global sea levels will rise in response to climate change.

Researchers expected to find some gaps between ice and bedrock at Thwaites' bottom where ocean water could flow in and melt the glacier from below. The size and explosive growth rate of the newfound hole, however, surprised them. It's big enough to have contained 14 billion tons of ice, and most of that ice melted over the last three years.

Thwaites Glacier. Image Credit: NASA/OIB/Jeremy Harbeck

"We have suspected for years that Thwaites was not tightly attached to the bedrock beneath it," said Eric Rignot of the University of California, Irvine, and NASA's Jet Propulsion Laboratory in Pasadena, California. Rignot is a co-author of the new study, which was published today in Science Advances. "Thanks to a new generation of satellites, we can finally see the detail," he said.

The cavity was revealed by ice-penetrating radar in NASA's Operation IceBridge, an airborne campaign beginning in 2010 that studies connections between the polar regions and the global climate. The researchers also used data from a constellation of Italian and German spaceborne synthetic aperture radars. These very high-resolution data can be processed by a technique called radar interferometry to reveal how the ground surface below has moved between images.

"[The size of] a cavity under a glacier plays an important role in melting," said the study's lead author, Pietro Milillo of JPL. "As more heat and water get under the glacier, it melts faster."

Numerical models of ice sheets use a fixed shape to represent a cavity under the ice, rather than allowing the cavity to change and grow. The new discovery implies that this limitation most likely causes those models to underestimate how fast Thwaites is losing ice.

About the size of Florida, Thwaites Glacier is currently responsible for approximately 4 percent of global sea level rise. It holds enough ice to raise the world ocean a little over 2 feet (65 centimeters) and backstops neighboring glaciers that would raise sea levels an additional 8 feet (2.4 meters) if all the ice were lost.

Animation above: Changes in surface height at Thwaites Glacier's grounding line, 2011 to 2017, with sinking areas in red and rising areas in blue. The growing cavity (red mass, center) caused the greatest sinking. The mottled area (bottom left) is the site of extensive calving. Contours show bedrock topography. Animation Credits: NASA/JPL-Caltech.

Thwaites is one of the hardest places to reach on Earth, but it is about to become better known than ever before. The U.S. National Science Foundation and British National Environmental Research Council are mounting a five-year field project to answer the most critical questions about its processes and features. The International Thwaites Glacier Collaboration will begin its field experiments in the Southern Hemisphere summer of 2019-20.

How Scientists Measure Ice Loss

There's no way to monitor Antarctic glaciers from ground level over the long term. Instead, scientists use satellite or airborne instrument data to observe features that change as a glacier melts, such as its flow speed and surface height.

Another changing feature is a glacier's grounding line - the place near the edge of the continent where it lifts off its bed and starts to float on seawater. Many Antarctic glaciers extend for miles beyond their grounding lines, floating out over the open ocean.

Just as a grounded boat can float again when the weight of its cargo is removed, a glacier that loses ice weight can float over land where it used to stick. When this happens, the grounding line retreats inland. That exposes more of a glacier's underside to sea water, increasing the likelihood its melt rate will accelerate.

An Irregular Retreat

For Thwaites, "We are discovering different mechanisms of retreat," Millilo said. Different processes at various parts of the 100-mile-long (160-kilometer-long) front of the glacier are putting the rates of grounding-line retreat and of ice loss out of sync.

The huge cavity is under the main trunk of the glacier on its western side - the side farther from the West Antarctic Peninsula. In this region, as the tide rises and falls, the grounding line retreats and advances across a zone of about 2 to 3 miles (3 to 5 kilometers). The glacier has been coming unstuck from a ridge in the bedrock at a steady rate of about 0.4 to 0.5 miles (0.6 to 0.8 kilometers) a year since 1992. Despite this stable rate of grounding-line retreat, the melt rate on this side of the glacier is extremely high.

"On the eastern side of the glacier, the grounding-line retreat proceeds through small channels, maybe a kilometer wide, like fingers reaching beneath the glacier to melt it from below," Milillo said. In that region, the rate of grounding-line retreat doubled from about 0.4 miles (0.6 kilometers) a year from 1992 to 2011 to 0.8 miles (1.2 kilometers) a year from 2011 to 2017. Even with this accelerating retreat, however, melt rates on this side of the glacier are lower than on the western side.

These results highlight that ice-ocean interactions are more complex than previously understood.

Milillo hopes the new results will be useful for the International Thwaites Glacier Collaboration researchers as they prepare for their fieldwork. "Such data is essential for field parties to focus on areas where the action is, because the grounding line is retreating rapidly with complex spatial patterns," he said.

"Understanding the details of how the ocean melts away this glacier is essential to project its impact on sea level rise in the coming decades," Rignot said.

The paper by Milillo and his co-authors in the journal Science Advances is titled "Heterogeneous retreat and ice melt of Thwaites Glacier, West Antarctica." Co-authors were from the University of California, Irvine; the German Aerospace Center in Munich, Germany; and the University Grenoble Alpes in Grenoble, France.

Related links:

Operation IceBridge:

International Thwaites Glacier Collaboration:

Image (mentioned), Animation (mentioned), Text, Credits: NASA/JPL/Esprit Smith/University of California/Brian Bell/NASA's Earth Science News Team, written by Carol Rasmussen.


NASA’s NICER Mission Maps ‘Light Echoes’ of New Black Hole

NASA - Neutron star Interior Composition Explorer (NICER) patch.

Jan. 30, 2019

Scientists have charted the environment surrounding a stellar-mass black hole that is 10 times the mass of the Sun using NASA’s Neutron star Interior Composition Explorer (NICER) payload aboard the International Space Station. NICER detected X-ray light from the recently discovered black hole, called MAXI J1820+070 (J1820 for short), as it consumed material from a companion star. Waves of X-rays formed “light echoes” that reflected off the swirling gas near the black hole and revealed changes in the environment’s size and shape.

“NICER has allowed us to measure light echoes closer to a stellar-mass black hole than ever before,” said Erin Kara, an astrophysicist at the University of Maryland, College Park and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who presented the findings at the 233rd American Astronomical Society meeting in Seattle. “Previously, these light echoes off the inner accretion disk were only seen in supermassive black holes, which are millions to billions of solar masses and undergo changes slowly. Stellar black holes like J1820 have much lower masses and evolve much faster, so we can see changes play out on human time scales.”

A paper describing the findings, led by Kara, appeared in the Jan. 10 issue of Nature and is available online:

NICER Charts the Area Around a New Black Hole

Video above: Watch how X-ray echoes, mapped by NASA’s Neutron star Interior Composition Explorer (NICER) revealed changes to the corona of black hole MAXI J1820+070. Video Credits: NASA’s Goddard Space Flight Center.

J1820 is located about 10,000 light-years away toward the constellation Leo. The companion star in the system was identified in a survey by ESA’s (European Space Agency) Gaia mission, which allowed researchers to estimate its distance. Astronomers were unaware of the black hole’s presence until March 11, 2018, when an outburst was spotted by the Japan Aerospace Exploration Agency’s Monitor of All-sky X-ray Image (MAXI), also aboard the space station. J1820 went from a totally unknown black hole to one of the brightest sources in the X-ray sky over a few days. NICER moved quickly to capture this dramatic transition and continues to follow the fading tail of the eruption.

“NICER was designed to be sensitive enough to study faint, incredibly dense objects called neutron stars,” said Zaven Arzoumanian, the NICER science lead at Goddard and a co-author of the paper. “We’re pleased at how useful it’s also proven in studying these very X-ray-bright stellar-mass black holes.”

A black hole can siphon gas from a nearby companion star into a ring of material called an accretion disk. Gravitational and magnetic forces heat the disk to millions of degrees, making it hot enough to produce X-rays at the inner parts of the disk, near the black hole. Outbursts occur when an instability in the disk causes a flood of gas to move inward, toward the black hole, like an avalanche. The causes of disk instabilities are poorly understood.

Above the disk is the corona, a region of subatomic particles around 1 billion degrees Celsius (1.8 billion degrees Fahrenheit) that glows in higher-energy X-rays. Many mysteries remain about the origin and evolution of the corona. Some theories suggest the structure could represent an early form of the high-speed particle jets these types of systems often emit.

Image above: In this illustration of a newly discovered black hole named MAXI J1820+070, a black hole pulls material off a neighboring star and into an accretion disk. Above the disk is a region of subatomic particles called the corona. Image Credits: Aurore Simonnet and NASA’s Goddard Space Flight Center.

Astrophysicists want to better understand how the inner edge of the accretion disk and the corona above it change in size and shape as a black hole accretes material from its companion star. If they can understand how and why these changes occur in stellar-mass black holes over a period of weeks, scientists could shed light on how supermassive black holes evolve over millions of years and how they affect the galaxies in which they reside.

One method used to chart those changes is called X-ray reverberation mapping, which uses X-ray reflections in much the same way sonar uses sound waves to map undersea terrain. Some X-rays from the corona travel straight toward us, while others light up the disk and reflect back at different energies and angles.

X-ray reverberation mapping of supermassive black holes has shown that the inner edge of the accretion disk is very close to the event horizon, the point of no return. The corona is also compact, lying closer to the black hole rather than over much of the accretion disk. Previous observations of X-ray echoes from stellar black holes, however, suggested the inner edge of the accretion disk could be quite distant, up to hundreds of times the size of the event horizon. The stellar-mass J1820, however, behaved more like its supermassive cousins. 

As they examined NICER’s observations of J1820, Kara’s team saw a decrease in the delay, or lag time, between the initial flare of X-rays coming directly from the corona and the flare’s echo off the disk, indicating that the X-rays traveled shorter and shorter distances before they were reflected. From 10,000 light-years away, they estimated that the corona contracted vertically from roughly 100 to 10 miles — that’s like seeing something the size of a blueberry shrink to something the size of a poppy seed at the distance of Pluto

Neutron star Interior Composition Explorer (NICER). Animation Credit: NASA

“This is the first time that we’ve seen this kind of evidence that it’s the corona shrinking during this particular phase of outburst evolution,” said co-author Jack Steiner, an astrophysicist at the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research in Cambridge. “The corona is still pretty mysterious, and we still have a loose understanding of what it is. But we now have evidence that the thing that’s evolving in the system is the structure of the corona itself.”

To confirm the decreased lag time was due to a change in the corona and not the disk, the researchers used a signal called the iron K line created when X-rays from the corona collide with iron atoms in the disk, causing them to fluoresce. Time runs slower in stronger gravitational fields and at higher velocities, as stated in Einstein’s theory of relativity. When the iron atoms closest to the black hole are bombarded by light from the core of the corona, the X-ray wavelengths they emit get stretched because time is moving slower for them than for the observer (in this case, NICER).

Kara’s team discovered that J1820’s stretched iron K line remained constant, which means the inner edge of the disk remained close to the black hole — similar to a supermassive black hole. If the decreased lag time was caused by the inner edge of the disk moving even further inward, then the iron K line would have stretched even more.

These observations give scientists new insights into how material funnels in to the black hole and how energy is released in this process.

Image above: The NICER instrument installed on the International Space Station, as captured by a high-definition external camera on Oct. 22, 2018. Image Credit: NASA.

“NICER’s observations of J1820 have taught us something new about stellar-mass black holes and about how we might use them as analogs for studying supermassive black holes and their effects on galaxy formation,” said co-author Philip Uttley, an astrophysicist at the University of Amsterdam. “We’ve seen four similar events in NICER’s first year, and it’s remarkable. It feels like we’re on the edge of a huge breakthrough in X-ray astronomy.”

NICER is an Astrophysics Mission of Opportunity within NASA's Explorer program, which provides frequent flight opportunities for world-class scientific investigations from space utilizing innovative, streamlined and efficient management approaches within the heliophysics and astrophysics science areas. NASA's Space Technology Mission Directorate supports the SEXTANT component of the mission, demonstrating pulsar-based spacecraft navigation.

Related links:

NASA’s Neutron star Interior Composition Explorer (NICER):

Monitor of All-sky X-ray Image (MAXI):

International Space Station (ISS):

Space Station Research and Technology:

NASA’s Goddard Space Flight Center (GSFC):

University of Maryland:

European Space Agency (ESA):

Japan Aerospace Exploration Agency (JAXA):

Images (mentioned), Animation (mentioned), Video (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Jeanette Kazmierczak.


mardi 29 janvier 2019

Station Crew Helping Future Orion Explorers

ISS - Expedition 58 Mission patch.

January 29, 2019

The International Space Station is providing a research platform today to help future astronauts navigate deep space in the Orion Multi-Purpose Crew Vehicle. The Expedition 58 crew is also testing new lights and setting up the orbital lab for CubeSat deployments.

NASA is planning deep space missions with its new Orion spacecraft that will rely on NASA’s Deep Space Network for communications and navigation. Flight Engineer David Saint-Jacques took photographs of the moon from the cupola today to calibrate Orion’s navigation software. The lunar data will provide additional navigation capability for Orion in the event of a loss of communication with the Deep Space Network.

Image above: The International Space Station photographed by departing Expedition 56 crew members aboard a Soyuz spacecraft after undocking on Oct. 4, 2018. Image Credit: NASA.

Another experiment geared towards future exploration taking place aboard the station is the Sextant study. As its name suggests, astronauts are testing a hand-held sextant to focus on stability and star-sighting opportunities while in microgravity. Results may aid future Orion explorers and provide a backup navigation source for missions far beyond Earth orbit.

Astronaut Anne McClain worked throughout the day inside Japan’s Kibo laboratory module. She is setting up the Kibo airlock with hardware to deploy a set of CubeSats on Thursday. The CubeSats have a variety of educational and technical mission objectives including studying the ionosphere and satellite communications.

Flying over auroras. Animation Credit: NASA

McClain later tested and photographed new lights that scientists are researching for their ability to improve crew sleep and performance. She also continued loading the Northrop Grumman Cygnus cargo craft with disposable gear before it departs from the Unity module Feb. 8.

Both McClain and Saint-Jacques joined Commander Oleg Kononenko early Tuesday for body mass measurements. Kononenko then moved on to life support maintenance, crew culture studies and radiation measurements aboard the orbital lab.

Related links:

Expedition 58:

Orion spacecraft:

Deep Space Network:



Kibo laboratory module:


Unity module:

Space Station Research and Technology:

International Space Station (ISS):

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

Best regards,

Warming Seas May Increase Frequency of Extreme Storms

NASA - EOS Aqua Mission logo.

Jan. 29, 2019

A new NASA study shows that warming of the tropical oceans due to climate change could lead to a substantial increase in the frequency of extreme rain storms by the end of the century.

Image above: An "anvil" storm cloud in the Midwestern U.S. Image Credit: UCAR.

The study team, led by Hartmut Aumann of NASA's Jet Propulsion Laboratory in Pasadena, California, combed through 15 years of data acquired by NASA's Atmospheric Infrared Sounder (AIRS) instrument over the tropical oceans to determine the relationship between the average sea surface temperature and the onset of severe storms.

They found that extreme storms — those producing at least 0.12 inches (3 millimeters) of rain per hour over a 16-mile (25-kilometer) area — formed when the sea surface temperature was higher than about 82 degrees Fahrenheit (28 degrees Celsius). They also found that, based on the data, 21 percent more storms form for every 1.8 degrees Fahrenheit (1 degree Celsius) that ocean surface temperatures rise.

"It is somewhat common sense that severe storms will increase in a warmer environment. Thunderstorms typically occur in the warmest season of the year," Aumann explained. "But our data provide the first quantitative estimate of how much they are likely to increase, at least for the tropical oceans."

Image above: A hurricane as seen by NASA's Atmospheric Infrared Sounder (AIRS) instrument. A hurricane is a large collection of extremely severe thunderstorms — seen here in dark blue. Each square pixel represents the measurements from a 10-by-10-mile (16-by-16-kilometer) area. At the time this image was taken, there were 140 of these extreme thunderstorms rotating about the eye of the hurricane. Image Credits: NASA/JPL-Caltech.

Currently accepted climate models project that with a steady increase of carbon dioxide in the atmosphere (1 percent per year), tropical ocean surface temperatures may rise by as much as 4.8 degrees Fahrenheit (2.7 degrees Celsius) by the end of the century. The study team concludes that if this were to happen, we could expect the frequency of extreme storms to increase by as much as 60 percent by that time.

EOS Aqua satellite. Image Credit: NASA

Although climate models aren't perfect, results like these can serve as a guideline for those looking to prepare for the potential effects a changing climate may have.

"Our results quantify and give a more visual meaning to the consequences of the predicted warming of the oceans," Aumann said. "More storms mean more flooding, more structure damage, more crop damage and so on, unless mitigating measures are implemented."

The peer-reviewed study was published in the December 2018 issue of the Geophysical Research Letters journal.

Aqua Satellite:


Images (mentioned), Text, Credits: NASA/Tony Greicius/JPL/Esprit Smith.


New Horizons' Newest and Best-Yet View of Ultima Thule

NASA - New Horizons Mission patch.

January 29, 2019

Image above: Best-Yet View of Ultima Thule. Image Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

The wonders – and mysteries – of Kuiper Belt object 2014 MU69 continue to multiply as NASA's New Horizons spacecraft beams home new images of its New Year's Day 2019 flyby target.

This image, taken during the historic Jan. 1 flyby of what's informally known as Ultima Thule, is the clearest view yet of this remarkable, ancient object in the far reaches of the solar system – and the first small "KBO" ever explored by a spacecraft.

Obtained with the wide-angle Multicolor Visible Imaging Camera (MVIC) component of New Horizons' Ralph instrument, this image was taken when the KBO was 4,200 miles (6,700 kilometers) from the spacecraft, at 05:26 UT (12:26 a.m. EST) on Jan. 1 – just seven minutes before closest approach. With an original resolution of 440 feet (135 meters) per pixel, the image was stored in the spacecraft's data memory and transmitted to Earth on Jan. 18-19. Scientists then sharpened the image to enhance fine detail. (This process – known as deconvolution – also amplifies the graininess of the image when viewed at high contrast.)

The oblique lighting of this image reveals new topographic details along the day/night boundary, or terminator, near the top. These details include numerous small pits up to about 0.4 miles (0.7 kilometers) in diameter. The large circular feature, about 4 miles (7 kilometers) across, on the smaller of the two lobes, also appears to be a deep depression. Not clear is whether these pits are impact craters or features resulting from other processes, such as "collapse pits" or the ancient venting of volatile materials.

Image above: Illustration of NASA’s New Horizons spacecraft encountering 2014 MU69 – nicknamed “Ultima Thule” – a Kuiper Belt object that orbits one billion miles beyond Pluto. New Horizons’ exploration of Ultima is the farthest space probe flyby in history. Image Credits: NASA/JHUAPL/SwRI.

Both lobes also show many intriguing light and dark patterns of unknown origin, which may reveal clues about how this body was assembled during the formation of the solar system 4.5 billion years ago. One of the most striking of these is the bright "collar" separating the two lobes.

"This new image is starting to reveal differences in the geologic character of the two lobes of Ultima Thule, and is presenting us with new mysteries as well," said Principal Investigator Alan Stern, of the Southwest Research Institute in Boulder, Colorado. "Over the next month there will be better color and better resolution images that we hope will help unravel the many mysteries of Ultima Thule."

New Horizons is approximately 4.13 billion miles (6.64 billion kilometers) from Earth, operating normally and speeding away from the Sun (and Ultima Thule) at more than 31,500 miles (50,700 kilometers) per hour. At that distance, a radio signal reaches Earth six hours and nine minutes after leaving the spacecraft.

Related article:

New Movie Shows Ultima Thule from an Approaching New Horizons

New Horizons LORRI website:

For more information on the New Horizons mission, visit:

Images (mentioned), Text, Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.


lundi 28 janvier 2019

Crew Tests Time Perception in Space and Real-Time Vital Signs Monitoring

ISS - Expedition 58 Mission patch.

January 28, 2019

The Expedition 58 astronauts explored time perception and tested a wearable body monitor aboard the International Space Station today. The orbital residents also packed a U.S. space freighter and set up tiny satellites controlled by students on Earth.

Image above: NASA astronaut Anne McClain is pictured exercising aboard the International Space Station inside the U.S. Destiny laboratory module. Image Credit: NASA.

Astronauts Anne McClain and David Saint-Jacques started Monday in the Columbus lab module learning how microgravity affects time perception. During the experiment the crew judges time length with results compared to ground tests. Scientists hypothesize that astronauts experience time passing at a faster rate than those of us here on Earth.

McClain then spent the rest of the day with Commander Oleg Kononenko setting up and monitoring SPHERES satellites in the Kibo lab module. High school students compete to design the best algorithms that control the basketball-sized satellites to mimic spacecraft maneuvers and formation flying.

International Space Station (ISS). Animation Credit: NASA

Saint-Jacques set up a wearable device called the Bio-Monitor to test its ability to measure vital signs with minimum interference during a normal day in space. The Canadian astronaut also continued packing the Cygnus cargo craft from Northrop Grumman ahead of its Feb. 8 departure from the Unity module.

Related links:

Expedition 58:

Columbus lab module:

Time perception:


Kibo lab module:


Cygnus cargo craft:

Unity module:

Space Station Research and Technology:

International Space Station (ISS):

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

Best regards,

All Systems Go As Parker Solar Probe Begins Second Sun Orbit

NASA - Parker Solar Probe Mission patch.

January 28, 2019

On Jan. 19, 2019, just 161 days after its launch from Cape Canaveral Air Force Station in Florida, NASA’s Parker Solar Probe completed its first orbit of the Sun, reaching the point in its orbit farthest from our star, called aphelion. The spacecraft has now begun the second of 24 planned orbits, on track for its second perihelion, or closest approach to the Sun, on April 4, 2019.

Parker Solar Probe closest approach to the Sun. Animation Credits: NASA/JHUAPL

Parker Solar Probe entered full operational status (known as Phase E) on Jan. 1, with all systems online and operating as designed. The spacecraft has been delivering data from its instruments to Earth via the Deep Space Network, and to date more than 17 gigabits of science data has been downloaded. The full dataset from the first orbit will be downloaded by April.

“It’s been an illuminating and fascinating first orbit,” said Parker Solar Probe Project Manager Andy Driesman, of the Johns Hopkins University Applied Physics Laboratory. “We’ve learned a lot about how the spacecraft operates and reacts to the solar environment, and I’m proud to say the team’s projections have been very accurate.” APL designed, built, and manages the mission for NASA.

“We’ve always said that we don’t know what to expect until we look at the data,” said Project Scientist Nour Raouafi, also of APL. “The data we have received hints at many new things that we’ve not seen before and at potential new discoveries. Parker Solar Probe is delivering on the mission’s promise of revealing the mysteries of our Sun.”

Image above: Parker Solar Probe’s position, speed and round-trip light time as of Jan. 28, 2019. Track the spacecraft online:

The Parker Solar Probe team is not only focused on analyzing the science data but also preparing for the second solar encounter, which will take place in about two months.

In preparation for that next encounter, the spacecraft’s solid state recorder is being emptied of files that have already been delivered to Earth. In addition, the spacecraft is receiving updated positional and navigation information (called ephemeris) and is being loaded with a new automated command sequence, which contains about one month’s worth of instructions.

Like the mission’s first perihelion in November 2018, Parker Solar Probe’s second perihelion in April will bring the spacecraft to a distance of about 15 million miles from the Sun – just over half the previous close solar approach record of about 27 million miles set by Helios 2 in 1976.

The spacecraft’s four instrument suites will help scientists begin to answer outstanding questions about the Sun’s fundamental physics — including how particles and solar material are accelerated out into space at such high speeds and why the Sun’s atmosphere, the corona, is so much hotter than the surface below.

Parker Solar Probe:

Animation (mentioned), Image (mentioned), Text, Credits: Johns Hopkins University Applied Physics Lab, by Geoff Brown.


Space Station Highlights: Week of January 21, 2019

ISS - Expedition 58 Mission patch.

Jan. 28, 2019

Last week, Expedition 58 crew members continued conducting science aboard the International Space Station along with packing the NG-10 Cygnus resupply vehicle for its departure from the station. Upon undocking, Cygnus will boost to an altitude and inclination ideal for satellite deployment and release small satellites from the SlingShot small satellite deployment system. The cargo craft will then begin its descent toward Earth for a fiery but safe demise over the Pacific Ocean.

International Space Station (ISS). Image Credit: NASA

Here are details about some of the science conducted in space this week:

Ongoing work to protect astronauts’ eyes
After performing dilution measures last week, crew members continued collecting data for the Fluid Shifts investigation this week, performing a lower body negative pressure imaging session. This NASA investigation collects, at various intervals, dilution measurements and baseline imaging to help determine the causes for severe and lasting physical changes seen in the eyes of astronauts during spaceflight and to support development of preventive measures. A shift of fluids to the head may contribute to these changes, so one possible intervention could be reversing this fluid shift with a lower body negative pressure device.

A day in space station life

Animation above: NASA astronaut works within the Life Sciences Glovebox as a part of the Rodent Research-8 investigation. Animation Credit: NASA.

Crew members participated in a conference and ground uplinked the file needed for a firmware update for the ISS Experience. Filmed over multiple months, ISS Experience documents daily life aboard the space station using cinematic virtual reality (VR). Videos cover different aspects of crew life, execution of science aboard the station and the international partnerships involved. 

Testing solution convection for better crystal growth

The crew installed a Biophysics-5 plate into the Fluids Integrated Rack (FIR) and Light Microscopy Module (LMM). This investigation tests whether the movement of molecules through a fluid, known as solution convection, enhances or suppresses formation of the dense liquid clusters from which crystals form. This could answer the question of why protein crystallization investigations in microgravity often generate unexpectedly low or high numbers of crystals.

Image above: The Japanese Experiment Module (JEM) Exposed Facility (EF). The JEM-EF is continuously exposed to the space environment and can hold up to 10 experiments at a time. Image Credit: NASA.

The FIR is a complementary fluid physics research facility designed to host investigations involving colloids, gels, bubbles, capillary action, phase changes, and other phenomena. The LMM, a modified flexible and state-of-the-art commercial light imaging microscope facility, provides researchers with a powerful diagnostic hardware and software tool in space.

Other work was performed on these investigations:

- MISSE-10 hosts a suite of eight NASA investigations aboard the Materials International Space Station Flight Facility (MISSE-FF):

- Lighting Effects examines whether changing from fluorescent light bulbs to solid-state light-emitting diodes (LEDs) with adjustable intensity and color can improve crew circadian rhythms, sleep, and cognitive performance:

- MSPR is a multi-purpose small payload rack in the Japanese Experiment Module (JEM) used for a variety of scientific experiments:

- Polar Express is a Cold Stowage managed facility for transport and storage of science samples at cryogenic temperatures (-80ºC) to and from the space station:

Related links:

Expedition 58:


Fluid Shifts:

ISS Experience:


Fluids Integrated Rack (FIR):

Light Microscopy Module (LMM):

Spot the Station:

Space Station Research and Technology:

International Space Station (ISS):

Animation (mentioned), Images (mentioned), Text, Credits: NASA/Michael Johnson/Vic Cooley, Lead Increment Scientist Expeditions 57/58.

Best regards,