samedi 16 juillet 2016

Resupply Rocket Launches on Two-Day Delivery Mission











ROSCOSMOS - Russian Vehicles patch.

July 16, 2016


Image above: The Progress 64 cargo craft launches on a two-day trip to the International Space Station. Image Credit: NASA TV.

Carrying more than three tons of food, fuel, and supplies for the International Space Station crew, the unpiloted ISS Progress 64 cargo craft launched at 5:41 p.m. EDT (3:41 a.m. Baikonur time July 17) from the Baikonur Cosmodrome in Kazakhstan.

At the time of launch, the International Space Station was flying about 250 miles over Eastern Chad.

video
Russian Cargo Ship Launches to the Space Station

Less than 10 minutes after launch, the resupply ship reached preliminary orbit and deployed its solar arrays and navigational antennas as planned. The Russian cargo craft will chase the station during the next two days before docking to the Pirs Docking Compartment at the orbiting laboratory at 8:22 p.m. Monday, July 18. The Progress 64 will spend more than six months docked at the outpost before departing in mid-January for its deorbit into the Earth’s atmosphere.

Beginning at 7:45 p.m. Monday, NASA Television will provide live coverage of Progress 64’s arrival at the space station’s Pirs Docking Compartment.

Watch live on NASA TV and online at: http://www.nasa.gov/nasatv

To join the online conversation about the International Space Station and Progress 63 on Twitter, follow @Space_Station and the hashtag #ISScargo.

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

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

Greetings, Orbiter.ch

NASA Sails Full-Speed Ahead in Solar System Exploration












NASA patch.

July 16, 2016

NASA's Juno is now poised to shine a spotlight on the origins and interior structure of the largest planet in our solar system. As we wait for Juno's first close-up images of Jupiter (to be taken Aug. 27 during the spacecraft's next pass by the planet), NASA continues to explore our solar system to help answer fundamental questions about how we came to be, where we are going and whether we are alone in the universe.

"Juno is the latest example of the extraordinary science we have to look forward to right in our own solar system," said NASA Planetary Division Director Jim Green. "There are many uncharted, promising worlds and objects we are eager to explore with our current and future missions."


Image above: This color view from NASA's Juno spacecraft is made from some of the first images taken by JunoCam after the spacecraft entered orbit around Jupiter on July 5th (UTC). Image Credits: NASA/JPL-Caltech/SwRI/MSSS.

The James Webb Space Telescope (Webb telescope), set to launch in 2018, can observe not only faint objects across the universe, but also all of our neighboring planets and their moons within our solar system. Webb's angular and spectral resolution will allow us to observe these targets with unprecedented sensitivity and even follow geologic activity.

With Juno exploring Jupiter, NASA is also intrigued by its largest moons.

Io's intense geological activity makes it the most volcanically active world in the solar system, something Webb could potentially follow-up with. And NASA has selected nine science instruments for a future mission to investigate whether Europa -- a mysterious moon that scientists believe to have a liquid ocean beneath its icy surface -- hosts habitable environments.

Hubble, with its suite of upgraded instruments, has captured Jupiter's auroras and found evidence of saltwater on Jupiter's largest moon, Ganymede. The mission has been extended another five years, and NASA expects it to continue to provide excellent science.

NASA's Cassini spacecraft continues exploring Saturn, its rings and moons, as it has since 2004. In 2017, during the final phase of its long mission, Cassini will complete 22 dives through the narrow gap between Saturn's outer atmosphere and its rings. This exciting set of orbits, called the Grand Finale, will be like a whole new mission, with new views and profound new scientific insights.


Image above: Sunlight glints off of Titan's northern seas this near-infrared, color mosaic from NASA's Cassini spacecraft. Image Credits: NASA/JPL/Univ. Arizona/Univ. Idaho.

Titan is one of the major satellites of Saturn, with a rich atmosphere and surface chemistry that has been observed extensively by Cassini and ESA's Huygens Probe. After Cassini's mission ends, Webb will begin operations, providing an excellent platform for continuing studies of Titan with its unique new capabilities.

On July 14, NASA celebrated the one-year anniversary of New Horizons' flyby of Pluto, which brought the world unprecedented views of the dwarf planet and its moon, Charon. The mission has been extended to study an object in the Kuiper belt, an icy field of early building blocks of the solar system packed with primordial organics.

NASA's Dawn mission set out to investigate the solar system's two largest asteroids remaining intact since their formation -- Vesta and dwarf planet Ceres. The mission has revealed strange, bright regions on Ceres with the highest concentration of carbonate minerals ever seen outside Earth.

video
 Flight Over Dwarf Planet Ceres

In September, NASA will launch OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer), the first U.S. mission to a near-Earth asteroid (Bennu) to collect a sample for return to Earth in 2023.  OSIRIS-REx will help unlock secrets of the history of our solar system, and shed light on how life may have come to be on our planet.

On our journey to Mars, we are closer than ever before to sending American astronauts to our neighboring Red Planet. The Opportunity and Curiosity rovers are traversing Martian soil, while MAVEN, the Mars Atmosphere and Volatile Evolution Mission, the Mars Reconnaissance Orbiter, and Mars Odyssey are cruising the Martian skies above. They are helping uncover Mars' past, present, and future by searching for clues in both the surface and the atmosphere.

Montage of planets. Image Credits: NASA/JPL

The next Mars rover scheduled for launch in 2020 is under construction, and NASA's InSight Mission to study the interior of the Red Planet is scheduled to launch in 2018.

"We are fortunate to live during a time when grand scientific quests are possible, and in a country that values curiosity and discovery as inherently noble pursuits," says Paul Hertz, Astrophysics Division Director at NASA Headquarters in Washington.

NASA has recently directed nine planetary missions to plan for continued operations through fiscal years 2017 and 2018, contingent on available resources: http://solarsystem.nasa.gov/missions/2016seniorreview

Related links:

James Webb Space Telescope (Webb telescope): http://www.nasa.gov/webb

Cassini spacecraft: http://www.nasa.gov/cassini

New Horizons spacecraft: http://www.nasa.gov/newhorizons

OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer): https://www.nasa.gov/mission_pages/osiris-rex/

Images (mentioned), Text, Credits: NASA/Felicia Chou/Video: NASA/JPL.

Greetings, Orbiter.ch

vendredi 15 juillet 2016

Weekly Recap From the Expedition Lead Scientist Week of July 4, 2016












ISS - International Space Station logo.

July 15, 2016

(Highlights: Week of July 4, 2016) - On a week when the International Space Station welcomed three new crew members, the current residents on the orbiting laboratory watched the skies over the Pacific Ocean as a super storm struck Asia.

NASA astronaut Jeff Williams powered up the hardware for the Cyclone Intensity Measurements from the International Space Station (Tropical Cyclone) investigation. Earth scientists wanted to collect data on Typhoon Nepartak in the Pacific Ocean as it neared Taiwan. The investigation uses a specialized, automated camera and other instruments to acquire data about the storms through one of the portals on the orbiting laboratory.


Image above: Typhoon Nepartak begins to make landfall in Southeast Asia. An investigation on the space station, Tropical Cyclone, collected data on this storm from space. Combined with information on sea-level surface temperatures and air pressure, scientists hope to more accurately predict the wind speed, strength and intensities of future cyclones prior to landfall. This information would assist emergency responders and coastal residents to better prepare for oncoming storms. Image Credit: NASA.

Scientists are demonstrating new techniques for accurate real-time measurement of the intensities of strong tropical cyclones by using passive instrumentation from low-Earth orbit. This method requires measurements of the temperature of the top of the eye wall clouds of the storm and the height of these clouds above sea level. Combined with information on sea-level surface temperatures and air pressure, scientists can more accurately predict the wind speed, strength and intensities of cyclones prior to landfall. This information would assist emergency responders and coastal residents to better prepare for oncoming storms.

After watching the storm develop on Earth, the station crew turned their attention inward to radiation detection in the orbiting laboratory with the Radi-N2 Neutron Field Study (Radi-N2) investigation. Williams NASA deployed eight radiation detectors around the orbiting laboratory. The Canadian Space Agency's bubble spectrometers, placed in predetermined locations throughout the station, measure neutron radiation levels while ignoring all other radiation. This investigation characterizes the station neutron environment, defining the risk posed to crew members’ health, and provides the data necessary to develop advanced protective measures for future spaceflight. Because neutrons carry no electrical charge, they have greater potential to penetrate the body and damage tissue. Radi-N2 will help doctors better understand the connections between neutron radiation, DNA damage and mutation rates and can be applied to other radiation health issues on Earth.


Image above: During the week when America celebrated Independence Day, NASA astronaut Jeff Williams captured this image of the distinctive coastline of Massachusetts and Rhode Island from the International Space Station. He posted it to his Twitter account -- @Astro_Jeff -- along with flyover images of the rest of the original 13 colonies that made up the United States. Image Credits: NASA/Jeff Williams.

Williams installed three new water pump tubes in the European Modular Cultivation System (EMCS) on the station. This plant incubator is an ESA (European Space Agency) experimental facility dedicated to studying plant biology in a reduced gravity environment. It supports the cultivation, stimulation, and crew-assisted operation of biological experiments under controlled conditions. It can provide dedicated life support for plants, including temperature, humidity, carbon dioxide and water supply as well as illumination and observation capabilities for scientists. The EMCS facility’s data and command capabilities allow experiment control by the crew and from ground, downlinking housekeeping, science, and image data.

International Space Station (ISS). Image Credit: NASA

The facility has already performed multi-generation experiments -- growing plants from seeds until those plants create new seeds -- and studies the effects of gravity and light on early development and growth. In the future, this facility may be used for experiments with insects, amphibia and invertebrates as well as studies with cell and tissue cultures.

Progress was made on other investigations and facilities this week, including BRIC NP, Mouse Epigenetics, Ex-HAM-Interstellar Carbonaceous Solids along with various other Ex-HAM samples, Meteor, ISS Ham, DOSIS-3D and 3D Printing in Zero-G.

Human research investigations conducted this week include Dose Tracker, Fine Motor Skills and Space Headaches.

Related links:

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (Tropical Cyclone) investigation: http://www.nasa.gov/mission_pages/station/research/experiments/1973.html

Radi-N2 Neutron Field Study (Radi-N2) investigation: http://www.nasa.gov/mission_pages/station/research/experiments/898.html

Mouse Epigenetics: http://www.nasa.gov/mission_pages/station/research/experiments/1992.html

Ex-HAM-Interstellar Carbonaceous Solids: http://www.nasa.gov/mission_pages/station/research/experiments/2052.html

Meteor: http://www.nasa.gov/mission_pages/station/research/experiments/1323.html

ISS Ham: http://www.nasa.gov/mission_pages/station/research/experiments/346.html

DOSIS-3D: http://www.nasa.gov/mission_pages/station/research/experiments/184.html

3D Printing in Zero-G: http://www.nasa.gov/mission_pages/station/research/experiments/1115.html

Dose Tracker: http://www.nasa.gov/mission_pages/station/research/experiments/1933.html

Fine Motor Skills: http://www.nasa.gov/mission_pages/station/research/experiments/1767.html

Space Headaches: http://www.nasa.gov/mission_pages/station/research/experiments/181.html

European Modular Cultivation System (EMCS): http://www.nasa.gov/mission_pages/station/research/experiments/345.html

European Space Agency (ESA): http://www.esa.int/ESA

Canadian Space Agency (CSA-ASC): http://www.asc-csa.gc.ca/eng/

Images (mentioned), Text, Credits: NASA/Kristine Rainey/John Love, Acting Lead Increment Scientist Expeditions 47 & 48.

Best regards Orbiter.ch

NASA's Next Mars Rover Progresses Toward 2020 Launch











NASA logo.

July 15, 2016

After an extensive review process and passing a major development milestone, NASA is ready to proceed with final design and construction of its next Mars rover, currently targeted to launch in the summer of 2020 and arrive on the Red Planet in February 2021.

The Mars 2020 rover will investigate a region of Mars where the ancient environment may have been favorable for microbial life, probing the Martian rocks for evidence of past life. Throughout its investigation, it will collect samples of soil and rock and cache them on the surface for potential return to Earth by a future mission.

“The Mars 2020 rover is the first step in a potential multi-mission campaign to return carefully selected and sealed samples of Martian rocks and soil to Earth,” said Geoffrey Yoder, acting associate administrator of NASA’s Science Mission Directorate in Washington. “This mission marks a significant milestone in NASA’s Journey to Mars – to determine whether life has ever existed on Mars, and to advance our goal of sending humans to the Red Planet.”


Image above: This image is from computer-assisted-design work on the Mars 2020 rover. The design leverages many successful features of NASA's Curiosity rover, which landed on Mars in 2012, but also adds new science instruments and a sampling system to carry out new goals for the 2020 mission. Image Credits: NASA/JPL-Caltech.

To reduce risk and provide cost savings, the 2020 rover will look much like its six-wheeled, one-ton predecessor, Curiosity, but with an array of new science instruments and enhancements to explore Mars as never before. For example, the rover will conduct the first investigation into the usability and availability of Martian resources, including oxygen, in preparation for human missions.

Mars 2020 will carry an entirely new subsystem to collect and prepare Martian rocks and soil samples that includes a coring drill on its arm and a rack of sample tubes. About 30 of these sample tubes will be deposited at select locations for return on a potential future sample-retrieval mission. In laboratories on Earth, specimens from Mars could be analyzed for evidence of past life on Mars and possible health hazards for future human missions.

Two science instruments mounted on the rover’s robotic arm will be used to search for signs of past life and determine where to collect samples by analyzing the chemical, mineral, physical and organic characteristics of Martian rocks. On the rover’s mast, two science instruments will provide high-resolution imaging and three types of spectroscopy for characterizing rocks and soil from a distance, also helping to determine which rock targets to explore up close.

A suite of sensors on the mast and deck will monitor weather conditions and the dust environment, and a ground-penetrating radar will assess sub-surface geologic structure.

The Mars 2020 rover will use the same sky crane landing system as Curiosity, but will have the ability to land in more challenging terrain with two enhancements, making more rugged sites eligible as safe landing candidates.


Image above: Mars Science Laboratory rover "Curiosity" sky crane landing system. Image Credits: NASA/JPL-Caltech.

"By adding what’s known as range trigger, we can specify where we want the parachute to open, not just at what velocity we want it to open,” said Allen Chen, Mars 2020 entry, descent and landing lead at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. "That shrinks our landing area by nearly half."

Terrain-relative navigation on the new rover will use onboard analysis of downward-looking images taken during descent, matching them to a map that indicates zones designated unsafe for landing.

"As it is descending, the spacecraft can tell whether it is headed for one of the unsafe zones and divert to safe ground nearby,” said Chen. "With this capability, we can now consider landing areas with unsafe zones that previously would have disqualified the whole area. Also, we can land closer to a specific science destination, for less driving after landing."

There will be a suite of cameras and a microphone that will capture the never-before-seen or heard imagery and sounds of the entry, descent and landing sequence. Information from the descent cameras and microphone will provide valuable data to assist in planning future Mars landings, and make for thrilling video.

"Nobody has ever seen what a parachute looks like as it is opening in the Martian atmosphere,” said JPL's David Gruel, assistant flight system manager for the Mars 2020 mission. “So this will provide valuable engineering information.”

Microphones have flown on previous missions to Mars, including NASA's Phoenix Mars Lander in 2008, but never have actually been used on the surface of the Red Planet.

"This will be a great opportunity for the public to hear the sounds of Mars for the first time, and it could also provide useful engineering information," said Mars 2020 Deputy Project Manager Matt Wallace of JPL.

Mars 2020 rover drawing. Image Credit: NASA

Once a mission receives preliminary approval, it must go through four rigorous technical and programmatic reviews – known as Key Decision Points (KDP) — to proceed through the phases of development prior to launch. Phase A involves concept and requirements definition, Phase B is preliminary design and technology development, Phase C is final design and fabrication, and Phase D is system assembly, testing, and launch. Mars 2020 has just passed its KDP-C milestone.

"Since Mars 2020 is leveraging the design and some spare hardware from Curiosity, a significant amount of the mission's heritage components have already been built during Phases A and B,” said George Tahu, Mars 2020 program executive at NASA Headquarters in Washington. "With the KDP to enter Phase C completed, the project is proceeding with final design and construction of the new systems, as well as the rest of the heritage elements for the mission."

The Mars 2020 mission is part of NASA's Mars Exploration Program. Driven by scientific discovery, the program currently includes two active rovers and three NASA spacecraft orbiting Mars. NASA also plans to launch a stationary Mars lander in 2018, InSight, to study the deep interior of Mars.

JPL manages the Mars 2020 project and the Mars Exploration Program for NASA's Science Mission Directorate in Washington.

Related link:

NASA’s Journey to Mars: http://www.nasa.gov/content/nasas-journey-to-mars

For more information about Mars 2020, visit: http://mars.nasa.gov/mars2020

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

Greetings, Orbiter.ch

New Horizons’ Top 10 Pluto Pics












NASA - New Horizons Mission logo.

July 15, 2016

One year ago, NASA’s New Horizons mission made history by exploring Pluto and its moons – giving humankind our first real look at this fascinating world on the frontier of our solar system.

Since those amazing days in July 2015 the New Horizons spacecraft has transmitted numerous images and many other kinds of data home for scientists and the public alike to study, analyze, and just plain love. From Pluto’s iconic “heart” and sweeping ice- mountain vistas to its flowing glaciers and dramatic blue skies, it’s hard to pick just one favorite picture. So the mission team has picked 10 – and in no special order, placed them here.”

Vast Glacial Flows
 
Jagged Ice Shorelines and Snowy Pits
 
Blue Skies 
 
Charon Becomes a Real World 
 
The Vistas of Pluto 
 
A Dynamic Duo: Pluto and Charon in Enhanced Color 
 
Strange Snakeskin Terrain 
 
Pluto’s Heart 
 
Far Away Snow-Capped Mountains 
 
Colorful Composition Maps of Pluto

The powerful instruments on New Horizons not only gave scientists insight on what Pluto looked like, their data also confirmed (or, in many cases, dispelled) their ideas of what Pluto was made of. These compositional maps – assembled using data from the Linear Etalon Imaging Spectral Array (LEISA) component of the Ralph instrument – indicate the regions rich in ices of methane (CH4), nitrogen (N2) and carbon monoxide (CO), and, of course, water ice (H2O).

For more information about New Horizons, visit: http://www.nasa.gov/mission_pages/newhorizons/main/index.html

Images, Text, Credits: NASA/JHUAPL/SwRI/Bill Keeter.

Best regards, Orbiter.ch

NASA’s SDO Takes a Spin












NASA - Solar Dynamics Observatory (SDO) patch.

July 15, 2016

On July 6, 2016, engineers instructed NASA’s Solar Dynamics Observatory, or SDO, to roll 360 degrees on one axis. SDO dutifully performed the seven-hour maneuver, while producing some dizzying data: For this period of time, SDO images – taken every 12 seconds – appeared to show the sun spinning, as if stuck on a pinwheel. This video was taken by SDO’s Atmospheric Imaging Assembly instrument in extreme ultraviolet wavelengths that are typically invisible to our eyes, but was colorized here in gold for easy viewing.

Animation Credits: NASA’s Goddard Space Flight Center/SDO/Joy Ng.

This maneuver happens twice a year to help SDO’s Helioseismic and Magnetic Imager, or HMI, instrument take precise measurements of the solar limb, the outer edge of the sun as seen by SDO. Were the sun perfectly spherical, this would be a much simpler task. But the solar surface is dynamic, leading to occasional distortions. This makes it hard for HMI to find the sun’s edge when it’s perfectly still. HMI’s biannual roll lets each part of the camera look at the entire perimeter of the sun, helping it map the sun’s shape much more precisely.

Solar Dynamics Observatory (SDO). Image Credits: NASA/GSFC

HMI tracks variations in the solar limb over time to help us understand how the shape of the sun changes with respect to the solar cycle, the sun’s 11-year pattern of solar activity. The more we know about what drives this activity – activity that can include giant eruptions of solar material and radiation that can create hazards for satellites and astronauts – the better we may someday predict its onset.

For more information about Solar Dynamics Observatory (SDO), visit: http://www.nasa.gov/mission_pages/sdo/main/index.html

Image (mentioned), Animation (mentioned), Text, Credtis: NASA’s Goddard Space Flight Center/Lina Tran/Rob Garner.

Greetings, Orbiter.ch

Hubble Spots a Secluded Starburst Galaxy











NASA - Hubble Space Telescope patch.

July 15, 2016


This image was taken by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS) and shows a starburst galaxy named MCG+07-33-027. This galaxy lies some 300 million light-years away from us, and is currently experiencing an extraordinarily high rate of star formation — a starburst.

Normal galaxies produce only a couple of new stars per year, but starburst galaxies can produce a hundred times more than that. As MCG+07-33-027 is seen face-on, the galaxy’s spiral arms and the bright star-forming regions within them are clearly visible and easy for astronomers to study.

In order to form newborn stars, the parent galaxy has to hold a large reservoir of gas, which is slowly depleted to spawn stars over time. For galaxies in a state of starburst, this intense period of star formation has to be triggered somehow — often this happens due to a collision with another galaxy. MCG+07-33-027, however, is special; while many galaxies are located within a large cluster of galaxies, MCG+07-33-027 is a field galaxy, which means it is rather isolated. Thus, the triggering of the starburst was most likely not due to a collision with a neighboring or passing galaxy and astronomers are still speculating about the cause. The bright object to the right of the galaxy is a foreground star in our own galaxy.

For more information about the Hubble Space Telescope, visit:

http://hubblesite.org/
http://www.nasa.gov/hubble
https://www.spacetelescope.org/

Image Credits: ESA/Hubble & NASA and N. Grogin (STScI)/Text Credits: European Space Agency/NASA/Ashley Morrow.

Greetings, Orbiter.ch

jeudi 14 juillet 2016

Chandra Finds Evidence for Violent Stellar Merger












NASA - Chandra X-ray Observatory patch.

July 14, 2016


Gamma-ray bursts, or GRBs, are some of the most violent and energetic events in the Universe. Although these events are the most luminous explosions in the universe, a new study using NASA’s Chandra X-ray Observatory, NASA’s Swift satellite and other telescopes suggests that scientists may be missing a majority of these powerful cosmic detonations.

Astronomers think that some GRBs are the product of the collision and merger of two neutron stars or a neutron star and a black hole. The new research gives the best evidence to date that such collisions will generate a very narrow beam, or jet, of gamma rays. If such a narrow jet is not pointed toward Earth, the GRB produced by the collision will not be detected.

Collisions between two neutron stars or a neutron star and black hole are expected to be strong sources of gravitational waves that could be detected whether or not the jet is pointed towards the Earth. Therefore, this result has important implications for the number of events that will be detectable by the Laser Interferometry Gravitational-Wave Observatory (LIGO) and other gravitational wave observatories.

On September 3, 2014, NASA’s Swift observatory picked up a GRB – dubbed GRB 140903A due to the date it was detected. Scientists used optical observations with the Gemini Observatory telescope in Hawaii to determine that GRB 140903A was located in a galaxy about 3.9 billion light years away, relatively nearby for a GRB.

The large panel in the graphic is an illustration showing the aftermath of a neutron star merger, including the generation of a GRB. In the center is a compact object – either a black hole or a massive neutron star – and in red is a disk of material left over from the merger, containing material falling towards the compact object. Energy from this infalling material drives the GRB jet shown in yellow. In orange is a wind of particles blowing away from the disk and in blue is material ejected from the compact object and expanding at very high speeds of about one tenth the speed of light.

The image on the left of the two smaller panels shows an optical view from the Discovery Channel Telescope (DCT) with GRB 140903A in the middle of the square and a close-up X-ray view from Chandra on the right. The bright star in the optical image is unrelated to the GRB.

NASA’s Chandra X-ray Observatory

The gamma-ray blast lasted less than two seconds. This placed it into the “short GRB” category, which astronomers think are the output from neutron star-neutron star or black hole-neutron star collisions eventually forming either a black hole or a neutron star with a strong magnetic field. (The scientific consensus is that GRBs that last longer than two seconds result from the collapse of a massive star.)

About three weeks after the Swift discovery of GRB 140903A, a team of researchers led by Eleonora Troja of the University of Maryland, College Park (UMD), observed the aftermath of the GRB in X-rays with Chandra.  Chandra observations of how the X-ray emission from this GRB decreases over time provide important information about the properties of the jet.

Specifically, the researchers found that the jet is beamed into an angle of only about five degrees based on the X-ray observations, plus optical observations with the Gemini Observatory and the DCT and radio observations with the National Science Foundation’s Karl G. Jansky Very Large Array. This is roughly equivalent to a circle with the diameter of your three middle fingers held at arms length. This means that astronomers are detecting only about 0.4% of this type of GRB when it goes off, since in most cases the jet will not be pointed directly at us.

Previous studies by other astronomers had suggested that these mergers could produce narrow jets. However, the evidence in those cases was not as strong because the rapid decline in light was not observed at multiple wavelengths, allowing for explanations not involving jets.

Several pieces of evidence link this event to the merger of two neutron stars, or between a neutron star and black hole. These include the properties of the gamma ray emission, the old age and the low rate of stars forming in the GRB’s host galaxy and the lack of a bright supernova. In some previous cases strong evidence for this connection was not found.

New studies have suggested that such mergers could be the production site of elements heavier than iron, such as gold. Therefore, the rate of these events is also important to estimate the total amount of heavy elements produced by these mergers and compare it with the amounts observed in the Milky Way galaxy.

A paper describing these results was recently accepted for publication in The Astrophysical Journal and is available online. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Read More from NASA's Chandra X-ray Observatory: http://chandra.harvard.edu/photo/2016/grb/

For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

The Astrophysical Journal: http://arxiv.org/abs/1605.03573

Images, Text, Credits: Illustration: CXC/M. Weiss; X-ray: NASA/CXC/Univ. of Maryland/E. Troja et al, Optical: Lowell Observatory's Discovery Channel Telescope/E. Troja et al./Lee Mohon.

Greetings, Orbiter.ch

One Year Later: New Horizons’ Top 10 Discoveries at Pluto












NASA - New Horizons logo.

July 14, 2016

Where were you at 7:49 a.m. Eastern Time on July 14, 2015?

Three billion miles from Earth, NASA’s New Horizons spacecraft, moving at speeds that would get it from New York to Los Angeles in about four minutes, was pointing cameras, spectrometers, and other sensors at Pluto and its moons – distant worlds that humankind had never seen up close – recording hundreds of pictures and other data that would forever change our view of the outer solar system.

“New Horizons not only completed the era of first reconnaissance of the planets, the mission has intrigued and inspired. Who knew that Pluto would have a heart?” said NASA’s Director of Planetary Science Jim Green. “Even today, New Horizons captures our imagination, rekindles our curiosity, and reminds us of what’s possible.” 


Image above: NASA's New Horizons spacecraft captured this high-resolution enhanced color view of Pluto's moon Charon just before closest approach on July 14, 2015. Charon’s striking reddish north polar region is informally named Mordor Macula. Image Credits: NASA/JHUAPL/SwRI.

To say that New Horizons shook the foundation of planetary science is an understatement—discoveries already culled from the pictures and compositional and space environment readings have not only introduced us to the Pluto system, but hint at what awaits as scientists examine other worlds in the Kuiper Belt. New Horizons Principal Investigator Alan Stern of the Southwest Research Institute, Boulder, Colorado, lists the mission’s most surprising and amazing findings from Pluto (so far):

- The complexity of Pluto and its satellites is far beyond what we expected.

- The degree of current activity on Pluto’s surface and the youth of some surfaces on Pluto are simply astounding.

- Pluto’s atmospheric hazes and lower-than-predicted atmospheric escape rate upended all of the pre-flyby models.

- Charon’s enormous equatorial extensional tectonic belt hints at the freezing of a former water ice ocean inside Charon in the distant past. Other evidence found by New Horizons indicates Pluto could well have an internal water-ice ocean today.

- All of Pluto’s moons that can be age-dated by surface craters have the same, ancient age—adding weight to the theory that they were formed together in a single collision between Pluto and another planet in the Kuiper Belt long ago.

- Charon’s dark, red polar cap is unprecedented in the solar system and may be the result of atmospheric gases that escaped Pluto and then accreted on Charon’s surface.

- Pluto’s vast 1,000-kilometer-wide heart-shaped nitrogen glacier (informally called Sputnik Planum) that New Horizons discovered is the largest known glacier in the solar system.

- Pluto shows evidence of vast changes in atmospheric pressure and, possibly, past presence of running or standing liquid volatiles on its surface – something only seen elsewhere on Earth, Mars and Saturn’s moon Titan in our solar system.

- The lack of additional Pluto satellites beyond what was discovered before New Horizons was unexpected.

- Pluto’s atmosphere is blue. Who knew?

“It’s strange to think that only a year ago, we still had no real idea of what the Pluto system was like,” said Hal Weaver, New Horizons project scientist from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. “But it didn’t take long for us to realize Pluto was something special, and like nothing we ever could have expected. We’ve been astounded by the beauty and complexity of Pluto and its moons and we’re excited about the discoveries still to come.”


Image above: Illustration of Pluto and its next science target, 2014 MU69, with the trajectory of New Horizons in yellow. Image Credit: Alex Parker.

New Horizons is now nearly 300 million miles beyond Pluto, speeding to its next destination deeper into the Kuiper Belt, following NASA approval of an extended mission. About 80 percent of the data stored on the spacecraft’s recorders has been sent to Earth; transmission of the remainder will be complete by October.

“Our entire team is proud to have accomplished the first exploration of Pluto and the Kuiper Belt—something many of us had worked to achieve since the 1990s,” said Stern. “The data that New Horizons sent back about Pluto and its system of moons has revolutionized planetary science and inspired people of all ages across the world about space exploration. It’s been a real privilege to be able to do that, for which I’ll be forever indebted to our team and our nation.”

For more information about New Horizons, visit: http://www.nasa.gov/mission_pages/newhorizons/main/index.html

Images (mentioned), Text, Credits: NASA/Bill Keeter.

Greetings, Orbiter.ch

mercredi 13 juillet 2016

Stellar Outburst Brings Water Snow Line Into View












ESO - European Southern Observatory logo.

13 July 2016

Artist’s impression of the water snowline around the young star V883 Orionis

The Atacama Large Millimeter/submillimeter Array (ALMA) has made the first ever resolved observation of a water snow line within a protoplanetary disc. This line marks where the temperature in the disc surrounding a young star drops sufficiently low for snow to form. A dramatic increase in the brightness of the young star V883 Orionis flash heated the inner portion of the disc, pushing the water snow line out to a far greater distance than is normal for a protostar, and making it possible to observe it for the first time. The results are published in the journal Nature on 14 July 2016.

ALMA image of the protoplanetary disc around V883 Orionis

Young stars are often surrounded by dense, rotating discs of gas and dust, known as protoplanetary discs, from which planets are born. The heat from a typical young solar-type star means that the water within a protoplanetary disc is gaseous up to distances of around 3 au from the star [1] — less than 3 times the average distance between the Earth and the Sun — or around 450 million kilometres [2]. Further out, due to the extremely low pressure, the water molecules transition directly from a gaseous state to form a patina of ice on dust grains and other particles. The region in the protoplanetary disc where water transitions between the gas and solid phases is known as the water snow line [3].

The star V883 Orionis in the constellation of Orion

But the star V883 Orionis is unusual. A dramatic increase in its brightness has pushed the water snow line out to a distance of around 40 au (about 6 billion kilometres or roughly the size of the orbit of the dwarf planet Pluto in our Solar System). This huge increase, combined with the resolution of ALMA at long baselines [4], has allowed a team led by Lucas Cieza (Millennium ALMA Disk Nucleus and Universidad Diego Portales, Santiago, Chile) to make the first ever resolved observations of a water snow line in a protoplanetary disc.

Shifting water snowline in V883 Orionis

The sudden brightening that V883 Orionis experienced is an example of what occurs when large amounts of material from the disc surrounding a young star fall onto its surface. V883 Orionis is only 30% more massive than the Sun, but thanks to the outburst it is experiencing, it is currently a staggering 400 times more luminous — and much hotter [5].

ALMA image of the protoplanetary disc around V883 Orionis (annotated)

Lead author Lucas Cieza explains: “The ALMA observations came as a surprise to us. Our observations were designed to look for disc fragmentation leading to planet formation. We saw none of that; instead, we found what looks like a ring at 40 au. This illustrates well the transformational power of ALMA, which delivers exciting results even if they are not the ones we were looking for.”

video
ALMA image of the protoplanetary disc around V883 Orionis

The bizarre idea of snow orbiting in space is fundamental to planet formation. The presence of water ice regulates the efficiency of the coagulation of dust grains — the first step in planet formation. Within the snow line, where water is vapourised, smaller, rocky planets like our own are believed to form. Outside the water snow line, the presence of water ice allows the rapid formation of cosmic snowballs, which eventually go on to form massive gaseous planets such as Jupiter.

video
Zooming on the protoplanetary disc around V883 Orionis

The discovery that these outbursts may blast the water snow line to about 10 times its typical radius is very significant for the development of good planetary formation models. Such outbursts are believed to be a stage in the evolution of most planetary systems, so this may be the first observation of a common occurrence. In that case, this observation from ALMA could contribute significantly to a better understanding of how planets throughout the Universe formed and evolved.

video
The protoplanetary disc around V883 Orionis (artist's impression)

Notes:

[1] 1 au, or one astronomical unit, is the mean distance between the Earth and the Sun, around 149.6 million kilometres.This unit is typically used to describe distances measured within the Solar System and planetary systems around other stars.

[2] This line was between the orbits of Mars and Jupiter during the formation of the Solar System, hence the rocky planets Mercury, Venus, Earth and Mars formed within the line, and the gaseous planets Jupiter, Saturn, Uranus and Neptune formed outside.

[3] The snow lines for other molecules, such as carbon monoxide and methane, have been observed previously with ALMA, at distances of greater than 30 au from the protostar within other protoplanetary discs. Water freezes at a relatively high temperature and this means that the water snow line is usually much too close to the protostar to observe directly.

[4] Resolution is the ability to discern that objects are separate. To the human eye, several bright torches at a distance would seem like a single glowing spot, and only at closer quarters would each torch be distinguishable. The same principle applies to telescopes, and these new observations have exploited the exquisite resolution of ALMA in its long baseline modes. The resolution of ALMA at the distance of V883 Orionis is about 12 au — enough to resolve the water snow line at 40 au in this outbursting system, but not for a typical young star.

[5] Stars like V883 Orionis are classed as FU Orionis stars, after the original star that was found to have this behaviour. The outbursts may last for hundreds of years.

More information:

This research was presented in a paper entitled “Imaging the water snow-line during a protostellar outburst”, by L. Cieza et al., to appear in Nature on 14 July 2016.

The team is composed of Lucas A. Cieza (Millennium ALMA Disk Nucleus; Universidad Diego Portales, Santiago, Chile), Simon Casassus (Universidad de Chile, Santiago, Chile), John Tobin (Leiden Observatory, Leiden University, The Netherlands), Steven Bos (Leiden Observatory, Leiden University, The Netherlands), Jonathan P. Williams (University of Hawaii at Manoa, Honolulu, Hawai`i, USA), Sebastian Perez (Universidad de Chile, Santiago, Chile), Zhaohuan Zhu (Princeton University, Princeton, New Jersey, USA), Claudio Cáceres (Universidad Valparaiso, Valparaiso, Chile), Hector Canovas (Universidad Valparaiso, Valparaiso, Chile), Michael M. Dunham (Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA), Antonio Hales (Joint ALMA Observatory, Santiago, Chile), Jose L. Prieto (Universidad Diego Portales, Santiago, Chile), David A. Principe (Universidad Diego Portales, Santiago, Chile), Matthias R. Schreiber (Universidad Valparaiso, Valparaiso, Chile), Dary Ruiz-Rodriguez (Australian National University, Mount Stromlo Observatory, Canberra, Australia) and Alice Zurlo (Universidad Diego Portales & Universidad de Chile, Santiago, Chile).

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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

Links:

Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1626/eso1626a.pdf

Photos of ALMA: http://www.eso.org/public/images/archive/search/?adv=&subject_name=Atacama%20Large%20Millimeter/submillimeter%20Array

For more information about ALMA, visit: https://www.eso.org/sci/facilities/alma.html

Images, Text, Credits: ESO/Richard Hook/A. Angelich (NRAO/AUI/NSF)/ALMA (ESO/NAOJ/NRAO)/ALMA//L. Cieza/IAU and Sky & Telescope/Videos: ALMA (ESO/NAOJ/NRAO)/L. Cieza./ESO/Digitized Sky Survey 2/N. Risinger (skysurvey.org)/M. Kornmesser. Music: Johan B. Monell.

Best regards, Orbiter.ch

SolarImpulse - From the new world of clean technology to the ancient world of solar worship











SolarImpulse - Around The World patch.

July 13, 2016

Today, André Borschberg’s legacy at Solar Impulse will be remembered as he closed Solar Impulse’s penultimate flight of the round-the-world tour with a flyover of the epic Egyptian Pyramids. He landed in Cairo, Egypt on July 13th at 05:10 UTC, 06:10AM CET, 01:10AM EDT after 48 hours and 50 minutes of flight from his takeoff in Seville, Spain.


At 3:00 UTC on July 13th, Solar Impulse will fly above the epic Egyptian pyramids at sunrise, while its solar cells absorb the first sun rays.


It is still a bit of a mystery why the Egyptian pyramids were built. But we always like to speculate about history. The shape of the pyramids is thought to represent the descending sun’s rays. Originally, the structures were thought to have been covered in a white limestone with a gold and silver finish on the top. The sun has always been a symbol of strength and today Solar Impulse is using it for it’s power - the power to fly emission-free using clean technology.

LEG 16: Solar Impulse Airplane - Landing in Cairo

Today, the sun’s rays are reaching Solar Impulse 2 both from above and below before landing in Cairo, Egypt for André Borschberg’s final landing with Si2 on the round-the-world solar flights. This is a monumental finish to celebrate André’s journey that was filled with both challenges and miracles. We will be communicating with you about it live on http://solarimpulse.com.

Images, Text, Credits: SolarImpulse.

Greetings, Orbiter.ch

NASA's Juno Spacecraft Sends First In-orbit View












NASA - JUNO Mission logo.

July 13,  2016

Artist's view of Juno spacecraft orbiting Jupiter. Image Credits: NASA/JPL-Caltech

The JunoCam camera aboard NASA's Juno mission is operational and sending down data after the spacecraft's July 4 arrival at Jupiter. Juno's visible-light camera was turned on six days after Juno fired its main engine and placed itself into orbit around the largest planetary inhabitant of our solar system. The first high-resolution images of the gas giant Jupiter are still a few weeks away.

"This scene from JunoCam indicates it survived its first pass through Jupiter's extreme radiation environment without any degradation and is ready to take on Jupiter," said Scott Bolton, principal investigator from the Southwest Research Institute in San Antonio. "We can't wait to see the first view of Jupiter's poles."

The new view was obtained on July 10, 2016, at 10:30 a.m. PDT (1:30 p.m. EDT, 5:30 UTC), when the spacecraft was 2.7 million miles (4.3 million kilometers) from Jupiter on the outbound leg of its initial 53.5-day capture orbit. The color image shows atmospheric features on Jupiter, including the famous Great Red Spot, and three of the massive planet's four largest moons -- Io, Europa and Ganymede, from left to right in the image.

"JunoCam will continue to take images as we go around in this first orbit," said Candy Hansen, Juno co-investigator from the Planetary Science Institute, Tucson, Arizona. "The first high-resolution images of the planet will be taken on August 27 when Juno makes its next close pass to Jupiter."


Image above: This color view from NASA's Juno spacecraft is made from some of the first images taken by JunoCam after the spacecraft entered orbit around Jupiter on July 5th (UTC). Image Credits: NASA/JPL-Caltech/SwRI/MSSS.

JunoCam is a color, visible-light camera designed to capture remarkable pictures of Jupiter's poles and cloud tops. As Juno's eyes, it will provide a wide view, helping to provide context for the spacecraft's other instruments. JunoCam was included on the spacecraft specifically for purposes of public engagement; although its images will be helpful to the science team, it is not considered one of the mission's science instruments.

The Juno team is currently working to place all images taken by JunoCam on the mission's website, where the public can access them.

During its mission of exploration, Juno will circle the Jovian world 37 times, soaring low over the planet's cloud tops -- as close as about 2,600 miles (4,100 kilometers). During these flybys, Juno will probe beneath the obscuring cloud cover of Jupiter and study 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. Juno is part of NASA's New Frontiers Program, which is managed at NASA's Marshall Space Flight Center in Huntsville, Alabama, for NASA's Science Mission Directorate. Michael Ravine of Malin Space Science Systems, San Diego, is the JunoCam instrument lead. Lockheed Martin Space Systems, Denver, built the spacecraft. Caltech in Pasadena manages JPL for NASA.

To see a full video of Jupiter and the Galilean moons during Juno's approach to Jupiter, visit: https://youtu.be/XpsQimYhNkA

More information on the Juno mission is available at: http://www.nasa.gov/juno

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

http://www.facebook.com/NASAJuno

http://www.twitter.com/NASAJuno

Images (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/JPL/DC Agle/Preston Dyches.

Greetings, Orbiter.ch

mardi 12 juillet 2016

Gravitational vortex provides new way to study matter close to a black hole
















ESA - XMM-Newton Mission patch / NASA - NuStar Mission patch.

12 July 2016

ESA's orbiting X-ray observatory, XMM-Newton, has proved the existence of a 'gravitational vortex' around a black hole. The discovery, aided by NASA's NuSTAR mission, solves a mystery that has eluded astronomers for more than 30 years and will allow them to map the behaviour of matter very close to black holes. It could also open the door to future investigations of Albert Einstein's general relativity.

 Matter falling into a black hole heats up as it plunges to its doom. Before it passes into the black hole and is lost from view forever, it can reach millions of degrees. At that temperature it shines X-rays into space.

In the 1980s, pioneering astronomers using early X-ray telescopes discovered that the X-rays coming from black holes flicker. The changes follow a set pattern. When the flickering begins, the dimming and re-brightening can take 10 seconds to complete. As the days, weeks and then months progress, the period shortens until the oscillation takes place 10 times every second. Then, the flickering suddenly stops altogether.


Artist's impression of the XMM-Newton observatory. Image Credit: ESA


 The phenomenon was dubbed the Quasi Periodic Oscillation (QPO). "It was immediately recognised to be something fascinating because it is coming from something very close to a black hole," says Adam Ingram, University of Amsterdam, The Netherlands, who began working to understand QPOs for his PhD in 2009.

During the 1990s, astronomers had begun to suspect that the QPOs were associated with a gravitational effect predicted by Einstein's general relativity: that a spinning object will create a kind of gravitational vortex.

"It is a bit like twisting a spoon in honey. Imagine that the honey is space and anything embedded in the honey will be 'dragged' around by the twisting spoon," explains Ingram. "In reality, this means that anything orbiting a spinning object will have its motion affected." In the case of an inclined orbit, it will 'precess'. This means that the whole orbit will change orientation around the central object. The time for the orbit to return to its initial condition is known as a precession cycle.

In 2004, NASA launched Gravity Probe B to measure this so-called Lense-Thirring effect around Earth. After painstaking analysis, scientists confirmed that the spacecraft would turn through a complete precession cycle once every 33 million years.

Around a black hole, however, the effect would be much more noticeable because of the stronger gravitational field. The precession cycle would take just a matter of seconds or less to complete. This is so close to the periods of the QPOs that astronomers began to suspect a link.

Ingram began working on the problem during his PhD, looking at what happened in the flat disc of matter surrounding a black hole. Known as an accretion disc, it is the place where material gradually spirals inwards towards the black hole. It had already been suggested that, close to the black hole, the flat accretion disc puffs up into a hot plasma, in which electrons are stripped from their host atoms. Termed the hot inner flow, it shrinks in size over weeks and months as it is eaten by the black hole. Together with colleagues, Ingram published a paper in 2009 suggesting that the QPO is driven by Lense-Thirring precession of this hot flow. This is because the smaller the inner flow becomes, the closer to the black hole it would approach and so the faster its Lense-Thirring precession cycle would be. The question was: how to prove it?

"We have spent a lot of time trying to find smoking gun evidence for this behaviour," says Ingram.


Image above: Artist's impression of a black-hole system that exhibits the Lense-Thirring effect. Image Credits: ESA/ATG medialab.

 The answer was that the inner flow is releasing high energy radiation that strikes the matter in the surrounding accretion disc, making the iron atoms in the disc shine like a fluorescent light tube. Instead of visible light, the iron releases X-rays of a single wavelength - referred to as 'a line'.

Because the accretion disc is rotating, the iron line has its wavelength distorted by the Doppler effect. Line emission from the approaching side of the disc is squashed – blue shifted – and line emission from the receding disc material is stretched – red shifted. If the inner flow really is precessing, it will sometimes shine on the approaching disc material and sometimes on the receding material, making the line wobble back and forth over the course of a precession cycle.

Seeing this wobbling is where XMM-Newton came in. Ingram and colleagues from Amsterdam, Cambridge, Durham, Southampton and Tokyo applied for a long duration observation that would allow them to watch the QPO repeatedly. They chose black hole H 1743-322, which was exhibiting a four-second QPO at the time. They watched it for 260,000 seconds with XMM-Newton. They also observed it for 70,000 seconds with NASA's NuSTAR X-ray observatory.

After a complicated analysis procedure to add all the observational data together, they saw that the iron line was wobbling in accordance with the predictions of general relativity. "We are directly measuring the motion of matter in a strong gravitational field near to a black hole," says Ingram.

This is the first time that the Lense-Thirring effect has been measured in a strong gravitational field. The technique will allow astronomers to map matter in the inner regions of accretion discs around black holes. It also hints at a powerful new tool with which to test general relativity.

Einstein's theory is largely untested in such strong gravitational fields. So if astronomers can understand the physics of the matter that is flowing into the black hole, they can use it to test the predictions of general relativity as never before - but only if the movement of the matter in the accretion disc can be completely understood.


Image above: Artist's impression of the Nuclear Spectroscopic Telescope Array (NuStar). Image Credit: NASA.

"If you can get to the bottom of the astrophysics, then you can really test the general relativity," says Ingram. A deviation from the predictions of general relativity would be welcomed by a lot of astronomers and physicists. It would be a concrete signal that a deeper theory of gravity exists.

Larger X-ray telescopes in the future could help in the search because they could collect the X-rays faster. This would allow astronomers to investigate the QPO phenomenon in more detail. But for now, astronomers can be content with having seen Einstein's gravity at play around a black hole.

"This is a major breakthrough since the study combines information about the timing and energy of X-ray photons to settle the 30-year debate around the origin of QPOs. The photon collecting capability of XMM-Newton was instrumental in this work," says Norbert Schartel, ESA Project Scientist for XMM-Newton.

More information:

The results reported in this article are published in "A quasi-periodic modulation of the iron line centroid energy in the black hole binary H 1743-322", by Adam Ingram and colleagues, to appear in Monthly Notices of the Royal Astronomical Society, 461 (2): 1967-1980; doi: 10.1093/mnras/stw1245: https://mnras.oxfordjournals.org/content/461/2/1967

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

NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA's Jet Propulsion Laboratory, also in Pasadena, for NASA's Science Mission Directorate in Washington.

Related links:

ESA's XMM-Newton: http://sci.esa.int/xmm-newton

NASA's NuSTAR X-ray observatory: http://www.nustar.caltech.edu/

NASA's Gravity Probe B: https://einstein.stanford.edu/

NASA's Press Release: https://www.nasa.gov/feature/jpl/black-hole-makes-material-wobble-around-it

Images (mentioned), Text, Credits: ESA/Norbert Schartel/Anton Pannekoek Institute for Astronomy University of Amsterdam/Adam Ingram.

Best regards, Orbiter.ch