vendredi 23 février 2018

Crew Goes into Weekend Preparing to Split Up on Tuesday









ISS - Expedition 54 Mission patch.

February 23, 2018


Image above: Flying over North Pacific Ocean seen by EarthCam on ISS, speed: 27'619 Km/h, altitude: 407,41 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 February 23, 2018 at 18:48 UTC.

Three Expedition 54 crew members are going into the weekend packing up and preparing to return to Earth on Tuesday. Commander Alexander Misurkin will lead fellow crew members Joe Acaba and Mark Vande Hei back to Earth inside the Soyuz MS-06 spacecraft Tuesday for a landing in south central Kazakhstan at 9:31 p.m. EST.

NASA TV will broadcast live all of the departure activities on Monday and Tuesday. The Change of Command Ceremony begins Monday at 2:40 p.m. when Misurkin hands over station control to cosmonaut Anton Shkaplerov. The new commander will stay behind with Flight Engineers Scott Tingle of NASA and Norishige Kanai of the Japan Aerospace Exploration Agency and become Expedition 55 when their crewmates undock the next day.


Image above: (Clockwise from bottom) Expedition 54 Commander Alexander Misurkin of Roscosmos; NASA astronauts Mark Vande Hei and Joe Acaba; Roscosmos cosmonaut Anton Shkaplerov; Astronaut Norishige Kanai of the Japan Aerospace Exploration Agency; NASA astronaut Scott Tingle. Image Credit: NASA.

The departing trio will say farewell Tuesday and close the Soyuz hatch at 2:15 p.m. They will undock from the Poisk module at 6:08 p.m. signifying the start of Expedition 55 and the end of Expedition 54. Next, the Soyuz engines will fire one last time at 8:38 p.m. sending the crew back into Earth’s atmosphere for a parachuted landing in Kazakhstan at 9:31 p.m.

The trio will have spent 168 days in space, orbiting Earth 2,688 times, conducted dozens of science experiments and seen the departure and arrival of eight different space ships. The departing crew members will also go home as experienced spacewalkers. Misurkin and Acaba each conducted one spacewalk and Vande Hei conducted four spacewalks during their five-and-half month stay in space.

Related links:

Expedition 54: https://www.nasa.gov/mission_pages/station/expeditions/expedition54/index.html

Expedition 55: https://www.nasa.gov/mission_pages/station/expeditions/expedition55/index.html

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

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

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

Best regards, Orbiter.ch

On Second Thought, the Moon's Water May Be Widespread and Immobile












NASA - Lunar Reconnaissance Orbiter (LRO) patch.

Feb. 23, 2018

A new analysis of data from two lunar missions finds evidence that the Moon’s water is widely distributed across the surface and is not confined to a particular region or type of terrain. The water appears to be present day and night, though it’s not necessarily easily accessible.

The findings could help researchers understand the origin of the Moon’s water and how easy it would be to use as a resource. If the Moon has enough water, and if it’s reasonably convenient to access, future explorers might be able to use it as drinking water or to convert it into hydrogen and oxygen for rocket fuel or oxygen to breathe.

“We find that it doesn’t matter what time of day or which latitude we look at, the signal indicating water always seems to be present,” said Joshua Bandfield, a senior research scientist with the Space Science Institute in Boulder, Colorado, and lead author of the new study published in Nature Geoscience. “The presence of water doesn’t appear to depend on the composition of the surface, and the water sticks around.”


Image above: If the Moon has enough water, and if it's reasonably convenient to access, future explorers might be able to use it as a resource. Image Credits: NASA's Goddard Space Flight Center.

The results contradict some earlier studies, which had suggested that more water was detected at the Moon’s polar latitudes and that the strength of the water signal waxes and wanes according to the lunar day (29.5 Earth days). Taking these together, some researchers proposed that water molecules can “hop” across the lunar surface until they enter cold traps in the dark reaches of craters near the north and south poles. In planetary science, a cold trap is a region that’s so cold, the water vapor and other volatiles which come into contact with the surface will remain stable for an extended period of time, perhaps up to several billion years.

The debates continue because of the subtleties of how the detection has been achieved so far. The main evidence has come from remote-sensing instruments that measured the strength of sunlight reflected off the lunar surface. When water is present, instruments like these pick up a spectral fingerprint at wavelengths near 3 micrometers, which lies beyond visible light and in the realm of infrared radiation.

But the surface of the Moon also can get hot enough to “glow,” or emit its own light, in the infrared region of the spectrum. The challenge is to disentangle this mixture of reflected and emitted light. To tease the two apart, researchers need to have very accurate temperature information.

Bandfield and colleagues came up with a new way to incorporate temperature information, creating a detailed model from measurements made by the Diviner instrument on NASA’s Lunar Reconnaissance Orbiter, or LRO. The team applied this temperature model to data gathered earlier by the Moon Mineralogy Mapper, a visible and infrared spectrometer that NASA’s Jet Propulsion Laboratory in Pasadena, California, provided for India’s Chandrayaan-1 orbiter.

The new finding of widespread and relatively immobile water suggests that it may be present primarily as OH, a more reactive relative of H2O that is made of one oxygen atom and one hydrogen atom. OH, also called hydroxyl, doesn’t stay on its own for long, preferring to attack molecules or attach itself chemically to them. Hydroxyl would therefore have to be extracted from minerals in order to be used.

The research also suggests that any H2O present on the Moon isn’t loosely attached to the surface.

“By putting some limits on how mobile the water or the OH on the surface is, we can help constrain how much water could reach the cold traps in the polar regions,” said Michael Poston of the Southwest Research Institute in San Antonio, Texas.

Sorting out what happens on the Moon could also help researchers understand the sources of water and its long-term storage on other rocky bodies throughout the solar system.

Lunar Reconnaissance Orbiter or LRO. Image Credit: NASA

The researchers are still discussing what the findings tell them about the source of the Moon’s water. The results point toward OH and/or H2O being created by the solar wind hitting the lunar surface, though the team didn’t rule out that OH and/or H2O could come from the Moon itself, slowly released from deep inside minerals where it has been locked since the Moon was formed.

“Some of these scientific problems are very, very difficult, and it’s only by drawing on multiple resources from different missions that are we able to hone in on an answer,” said LRO project scientist John Keller of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

LRO is managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland, for the Science Mission Directorate at NASA Headquarters in Washington, D.C. JPL designed, built and manages the Diviner instrument.

Read the paper in Nature Geoscience: http://dx.doi.org/10.1038/s41561-018-0065-0

LRO (Lunar Reconnaissance Orbiter): http://www.nasa.gov/mission_pages/LRO/main/index.html

Images (mentioned), Text, Credits: NASA/Karl Hille/Goddard Space Flight Center, by Elizabeth Zubritsky.

Greetings, Orbiter.ch

NASA’s SDO Reveals How Magnetic Cage on the Sun Stopped Solar Eruption












NASA - Solar Dynamics Observatory (SDO) patch.

Feb. 23, 2018

A dramatic magnetic power struggle at the Sun’s surface lies at the heart of solar eruptions, new research using NASA data shows. The work highlights the role of the Sun’s magnetic landscape, or topology, in the development of solar eruptions that can trigger space weather events around Earth.

Solar Dynamics Observatory, or SDO. Image Credit: NASA

The scientists, led by Tahar Amari, an astrophysicist at the Center for Theoretical Physics at the École Polytechnique in Palaiseau Cedex, France, considered solar flares, which are intense bursts of radiation and light. Many strong solar flares are followed by a coronal mass ejection, or CME, a massive, bubble-shaped eruption of solar material and magnetic field, but some are not — what differentiates the two situations is not clearly understood. 

Using data from NASA’s Solar Dynamics Observatory, or SDO, the scientists examined an October 2014 Jupiter-sized sunspot group, an area of complex magnetic fields, often the site of solar activity. This was the biggest group in the past two solar cycles and a highly active region. Though conditions seemed ripe for an eruption, the region never produced a major CME on its journey across the Sun. It did, however, emit a powerful X-class flare, the most intense class of flares. What determines, the scientists wondered, whether a flare is associated with a CME?


Animation above: On Oct. 24, 2014, NASA’s SDO observed an X-class solar flare erupt from a Jupiter-sized sunspot group. Animation Credits: Tahar Amari et al./Center for Theoretical Physics/École Polytechnique/NASA Goddard/Joy Ng.

The team of scientists included SDO’s observations of magnetic fields at the Sun’s surface in powerful models that calculate the magnetic field of the Sun’s corona, or upper atmosphere, and examined how it evolved in the time just before the flare. The model reveals a battle between two key magnetic structures: a twisted magnetic rope — known to be associated with the onset of CMEs — and a dense cage of magnetic fields overlying the rope.

The scientists found that this magnetic cage physically prevented a CME from erupting that day. Just hours before the flare, the sunspot’s natural rotation contorted the magnetic rope and it grew increasingly twisted and unstable, like a tightly coiled rubber band. But the rope never erupted from the surface: Their model demonstrates it didn’t have enough energy to break through the cage. It was, however, volatile enough that it lashed through part of the cage, triggering the strong solar flare.

By changing the conditions of the cage in their model, the scientists found that if the cage were weaker that day, a major CME would have erupted on Oct. 24, 2014. The group is interested in further developing their model to study how the conflict between the magnetic cage and rope plays out in other eruptions. Their findings are summarized in a paper published in Nature on Feb. 8, 2018.

“We were able to follow the evolution of an active region, predict how likely it was to erupt, and calculate the maximum amount of energy the eruption can release,” Amari said. “This is a practical method that could become important in space weather forecasting as computational capabilities increase.”


Image above: In this series of images, the magnetic rope, in blue, grows increasingly twisted and unstable. But it never erupts from the Sun’s surface: The model demonstrates the rope didn’t have enough energy to break through the magnetic cage, in yellow. Image Credits: Tahar Amari et al./Center for Theoretical Physics/École Polytechnique/NASA Goddard/Joy Ng.

Related:

Nature Feb. 8, 2018: https://www.nature.com/articles/nature24671

NASA Watches the Sun Put a Stop to Its Own Eruption: https://www.nasa.gov/feature/goddard/2017/nasa-watches-the-sun-put-a-stop-to-its-own-eruption

Two Weeks in the Life of a Sunspot: https://www.nasa.gov/feature/goddard/2017/two-weeks-in-the-life-of-a-sunspot/

NASA’s Solar Dynamics Observatory (SDO): http://nasa.gov/sdo

Images (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Lina Tran.

Greetings, Orbiter.ch

Time-lapse Sequence of Jupiter's South Pole












NASA - JUNO Mission logo.

February 23, 2018


This series of images captures cloud patterns near Jupiter's south pole, looking up towards the planet's equator.

NASA's Juno spacecraft took the color-enhanced time-lapse sequence of images during its eleventh close flyby of the gas giant planet on Feb. 7 between 7:21 a.m. and 8:01 a.m. PST (10:21 a.m. and 11:01 a.m. EST). At the time, the spacecraft was between 85,292 to 124,856 miles (137,264 to 200,937 kilometers) from the tops of the clouds of the planet with the images centered on latitudes from 84.1 to 75.5 degrees south.

At first glance, the series might appear to be the same image repeated. But closer inspection reveals slight changes, which are most easily noticed by comparing the far left image with the far right image.

Directly, the images show Jupiter. But, through slight variations in the images, they indirectly capture the motion of the Juno spacecraft itself, once again swinging around a giant planet hundreds of millions of miles from Earth.

Citizen scientist Gerald Eichstädt processed this image using data from the JunoCam imager.

JunoCam's raw images are available at http://www.missionjuno.swri.edu/junocam for the public to peruse and process into image products.

More information about Juno is online at http://www.nasa.gov/juno and http://missionjuno.swri.edu.

Juno spacecraft orbiting Jupiter

NASA's Jet Propulsion Laboratory 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. Lockheed Martin Space Systems, Denver, built the spacecraft. Caltech in Pasadena, California, manages JPL for NASA.

Image, Animation, Text, Credits: NASA/Gerald Eichstädt.

Greetings, Orbiter.ch

Swarm trio becomes a quartet








ESA - SWARM Mission logo.

February 23, 2018

With the aim of making the best possible use of existing satellites, ESA and Canada have made a deal that turns Swarm into a four-satellite mission to shed even more light on space weather and features such as the aurora borealis.

In orbit since 2013, ESA’s three identical Swarm satellites have been returning a wealth of information about how our magnetic field is generated and how it protects us from dangerous electrically charged atomic particles in the solar wind.

Aurora from above

Canada’s Cassiope satellite carries three instrument packages, one of which is e-POP.  It delivers information on space weather which complements that provided by Swarm. Therefore, the mission teams began looking into how they could work together to make the most of the two missions.

To make life easier, it also just so happens that Cassiope’s orbit is ideal to improve Swarm’s readings.

And now, thanks to this international cooperation and formalised through ESA’s Third Party Mission programme, e-POP has effectively become a fourth element of the Swarm mission. It joins Swarm’s Alpha, Bravo and Charlie satellites as Echo.

Josef Aschbacher, ESA’s Director of Earth Observation Programmes, noted, “This is a textbook example of how virtual constellations and collaborative initiatives can be realised, even deep into the missions’ exploitation phases.

“We embrace the opportunity to include e-POP in the Swarm mission, especially because it is clear that the more data we get, the better the picture we have of complex space weather dynamics.

Cassiope carries e-POP

“ESA is looking forward to seeing the fruits of this collaboration and the improved return on investment for both Europe and Canada.”

Andrew Yau from the University of Calgary added, “Swarm and e-POP have several unique measurement capabilities that are highly complementary.

“By integrating e-POP into the Swarm constellation, the international scientific community will be able to pursue a host of new scientific investigations into magnetosphere–ionosphere coupling, including Earth’s magnetic field and related current systems, upper-atmospheric dynamics and aurora dynamics.”

Birkeland currents

John Manuel from the Canadian Space Agency noted, “We are pleased to see e-POP join ESA’s three Swarm satellites in their quest to unravel the mysteries of Earth's magnetic field.

“Together, they will further improve our understanding of Earth's magnetic field and role it plays in shielding Canada and the world from the effects of space weather.”

Giuseppe Ottavianelli, Third-Party Mission Manager at ESA concluded, “I am pleased that the e-POP ensemble is now formally integrated into our Swarm constellation.

The force that protects our planet

“This milestone achievement confirms the essential role of ESA’s Earthnet programme, enabling synergies across missions, fostering international cooperation, and supporting data access.”

While e-POP changes its name to Echo as part of the Swarm mission, it will also continue to provide information for its original science investigations.

Related links:

Swarm: http://www.esa.int/Our_Activities/Observing_the_Earth/Swarm

Swarm technical info & data: https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/swarm

CASSIOPE: https://epop.phys.ucalgary.ca/cassiope/

e-POP: https://epop.phys.ucalgary.ca/

University of Calgary: http://www.ucalgary.ca/

Canadian Space Agency: http://www.asc-csa.gc.ca/eng/

ESA Third Party Missions: https://earth.esa.int/web/guest/missions/3rd-party-missions/overview

Images, Videos, Text, Credits: ESA/AOES Medialab/Canadian Space Agency/University of Calgary.

Best regards, Orbiter.ch

jeudi 22 février 2018

Astronauts Open BEAM and Prepare for Crew Departure









ISS - Expedition 54 Mission patch.

February 22, 2018


Image above: Sunrise over South China Sea seen by EarthCam on ISS, speed: 27'613 Km/h, altitude: 405,33 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 February 22, 2018 at 22:35 UTC.

Three Expedition 54 crew members continued preparing for their return to Earth next week. A pair of astronauts also opened up BEAM today to stow a robotic hand and to check for contaminants.

Commander Alexander Misurkin joined his Soyuz MS-06 crewmates Joe Acaba and Mark Vande Hei and reviewed their procedures for next week’s descent into Earth’s atmosphere. The trio also familiarized themselves with the sensations they will experience flying through the atmosphere and feeling gravity for the first time after 168 days in space.

Misurkin will hand over command of the International Space Station to cosmonaut Anton Shkaplerov on Monday at 2:40 p.m. EST. Misurkin, Vande Hei and Acaba will then close the hatch to their Soyuz spacecraft Tuesday at 2:15 p.m. and undock from the Poisk module 6:08 p.m. The trio will then parachute to a landing in Kazakhstan at 9:32 p.m. NASA TV will cover all the landing activities live.


Image above: Expedition 53-54 crew members (from left) Joe Acaba, Alexander Misurkin and Mark Vande Hei pose for a portrait inside the Japanese Kibo Laboratory module. Image Credit: NASA.

Flight Engineers Scott Tingle and Norishige Kanai will stay behind on the station with Shkaplerov as commander officially becoming the Expedition 55 crew when their crew mates undock next week. They will be joined March 23 by new Expedition 55-56 crew members Oleg Artemyev, Ricky Arnold and Drew Feustel. The trio will launch March 21 and were in Red Square in Moscow today for traditional ceremonial activities.

Today, Tingle and Kanai opened up the Bigelow Expandable Activity Module (BEAM) and stowed a degraded robotic hand, or Latching End Effector (LEE), that was attached to the Canadarm2. The LEE was returned inside the station after last week’s robotics maintenance spacewalk. The duo also sampled BEAM’s air and surfaces for microbes.

Related links:

NASA TV: https://www.nasa.gov/multimedia/nasatv/index.html

BEAM: https://www.nasa.gov/content/bigelow-expandable-activity-module

Expedition 54: https://www.nasa.gov/mission_pages/station/expeditions/expedition54/index.html

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

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

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

Greetings, Orbiter.ch

Improved Hubble Yardstick Gives Fresh Evidence for New Physics in the Universe











NASA - Hubble Space Telescope patch.

Feb. 22, 2018

Astronomers have used NASA's Hubble Space Telescope to make the most precise measurements of the expansion rate of the universe since it was first calculated nearly a century ago. Intriguingly, the results are forcing astronomers to consider that they may be seeing evidence of something unexpected at work in the universe.

That's because the latest Hubble finding confirms a nagging discrepancy showing the universe to be expanding faster now than was expected from its trajectory seen shortly after the big bang. Researchers suggest that there may be new physics to explain the inconsistency.

"The community is really grappling with understanding the meaning of this discrepancy," said lead researcher and Nobel Laureate Adam Riess of the Space Telescope Science Institute (STScI) and Johns Hopkins University, both in Baltimore, Maryland.


Image above: This illustration shows three steps astronomers used to measure the universe's expansion rate (Hubble constant) to an unprecedented accuracy, reducing the total uncertainty to 2.3 percent. The measurements streamline and strengthen the construction of the cosmic distance ladder, which is used to measure accurate distances to galaxies near to and far from Earth. The latest Hubble study extends the number of Cepheid variable stars analyzed to distances of up to 10 times farther across our galaxy than previous Hubble results. Image Credits: NASA, ESA, A. Feild (STScI), and A. Riess (STScI/JHU).

Riess's team, which includes Stefano Casertano, also of STScI and Johns Hopkins, has been using Hubble over the past six years to refine the measurements of the distances to galaxies, using their stars as milepost markers. Those measurements are used to calculate how fast the universe expands with time, a value known as the Hubble constant. The team’s new study extends the number of stars analyzed to distances up to 10 times farther into space than previous Hubble results.

But Riess's value reinforces the disparity with the expected value derived from observations of the early universe's expansion, 378,000 years after the big bang — the violent event that created the universe roughly 13.8 billion years ago. Those measurements were made by the European Space Agency's Planck satellite, which maps the cosmic microwave background, a relic of the big bang. The difference between the two values is about 9 percent. The new Hubble measurements help reduce the chance that the discrepancy in the values is a coincidence to 1 in 5,000.

Planck's result predicted that the Hubble constant value should now be 67 kilometers per second per megaparsec (3.3 million light-years), and could be no higher than 69 kilometers per second per megaparsec. This means that for every 3.3 million light-years farther away a galaxy is from us, it is moving 67 kilometers per second faster. But Riess's team measured a value of 73 kilometers per second per megaparsec, indicating galaxies are moving at a faster rate than implied by observations of the early universe.

The Hubble data are so precise that astronomers cannot dismiss the gap between the two results as errors in any single measurement or method. "Both results have been tested multiple ways, so barring a series of unrelated mistakes," Riess explained, "it is increasingly likely that this is not a bug but a feature of the universe."

Explaining a Vexing Discrepancy

Riess outlined a few possible explanations for the mismatch, all related to the 95 percent of the universe that is shrouded in darkness. One possibility is that dark energy, already known to be accelerating the cosmos, may be shoving galaxies away from each other with even greater — or growing — strength. This means that the acceleration itself might not have a constant value in the universe but changes over time in the universe. Riess shared a Nobel Prize for the 1998 discovery of the accelerating universe.

Another idea is that the universe contains a new subatomic particle that travels close to the speed of light. Such speedy particles are collectively called "dark radiation" and include previously-known particles like neutrinos, which are created in nuclear reactions and radioactive decays. Unlike a normal neutrino, which interacts by a subatomic force, this new particle would be affected only by gravity and is dubbed a "sterile neutrino."

Yet another attractive possibility is that dark matter (an invisible form of matter not made up of protons, neutrons, and electrons) interacts more strongly with normal matter or radiation than previously assumed.

Any of these scenarios would change the contents of the early universe, leading to inconsistencies in theoretical models. These inconsistencies would result in an incorrect value for the Hubble constant, inferred from observations of the young cosmos. This value would then be at odds with the number derived from the Hubble observations.

Riess and his colleagues don't have any answers yet to this vexing problem, but his team will continue to work on fine-tuning the universe's expansion rate. So far, Riess's team, called the Supernova H0 for the Equation of State (SH0ES), has decreased the uncertainty to 2.3 percent. Before Hubble was launched in 1990, estimates of the Hubble constant varied by a factor of two. One of Hubble's key goals was to help astronomers reduce the value of this uncertainty to within an error of only 10 percent. Since 2005, the group has been on a quest to refine the accuracy of the Hubble constant to a precision that allows for a better understanding of the universe's behavior.

Building a Strong Distance Ladder

The team has been successful in refining the Hubble constant value by streamlining and strengthening the construction of the cosmic distance ladder, which the astronomers use to measure accurate distances to galaxies near to and far from Earth. The researchers have compared those distances with the expansion of space as measured by the stretching of light from receding galaxies. They then have used the apparent outward velocity of galaxies at each distance to calculate the Hubble constant.

But the Hubble constant's value is only as precise as the accuracy of the measurements. Astronomers cannot use a tape measure to gauge the distances between galaxies. Instead, they have selected special classes of stars and supernovae as cosmic yardsticks or milepost markers to precisely measure galactic distances.

Among the most reliable for shorter distances are Cepheid variables, pulsating stars that brighten and dim at rates that correspond to their intrinsic brightness. Their distances, therefore, can be inferred by comparing their intrinsic brightness with their apparent brightness as seen from Earth.


Image above: These Hubble Space Telescope images showcase two of the 19 galaxies analyzed in a project to improve the precision of the universe's expansion rate, a value known as the Hubble constant. The color-composite images show NGC 3972 (left) and NGC 1015 (right), located 65 million light-years and 118 million light-years, respectively, from Earth. The yellow circles in each galaxy represent the locations of pulsating stars called Cepheid variables. Image Credits: NASA, ESA, A. Riess (STScI/JHU).

Astronomer Henrietta Leavitt was the first to recognize the utility of Cepheid variables to gauge distances in 1913. But the first step is to measure the distances to Cepheids independent of their brightness, using a basic tool of geometry called parallax. Parallax is the apparent shift of an object's position due to a change in an observer's point of view. This technique was invented by the ancient Greeks who used it to measure the distance from Earth to the Moon.

The latest Hubble result is based on measurements of the parallax of eight newly analyzed Cepheids in our Milky Way galaxy. These stars are about 10 times farther away than any studied previously, residing between 6,000 light-years and 12,000 light-years from Earth, making them more challenging to measure. They pulsate at longer intervals, just like the Cepheids observed by Hubble in distant galaxies containing another reliable yardstick, exploding stars called Type Ia supernovae. This type of supernova flares with uniform brightness and is brilliant enough to be seen from relatively farther away. Previous Hubble observations studied 10 faster-blinking Cepheids located 300 light-years to 1,600 light-years from Earth.

Scanning the Stars

To measure parallax with Hubble, the team had to gauge the apparent tiny wobble of the Cepheids due to Earth's motion around the Sun. These wobbles are the size of just 1/100 of a single pixel on the telescope's camera, which is roughly the apparent size of a grain of sand seen 100 miles away.

Therefore, to ensure the accuracy of the measurements, the astronomers developed a clever method that was not envisioned when Hubble was launched. The researchers invented a scanning technique in which the telescope measured a star's position a thousand times a minute every six months for four years.

The team calibrated the true brightness of the eight slowly pulsating stars and cross-correlated them with their more distant blinking cousins to tighten the inaccuracies in their distance ladder. The researchers then compared the brightness of the Cepheids and supernovae in those galaxies with better confidence, so they could more accurately measure the stars' true brightness, and therefore calculate distances to hundreds of supernovae in far-flung galaxies with more precision.

Another advantage to this study is that the team used the same instrument, Hubble's Wide Field Camera 3, to calibrate the luminosities of both the nearby Cepheids and those in other galaxies, eliminating the systematic errors that are almost unavoidably introduced by comparing those measurements from different telescopes.

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

"Ordinarily, if every six months you try to measure the change in position of one star relative to another at these distances, you are limited by your ability to figure out exactly where the star is," Casertano explained. Using the new technique, Hubble slowly slews across a stellar target, and captures the image as a streak of light. "This method allows for repeated opportunities to measure the extremely tiny displacements due to parallax," Riess added. "You're measuring the separation between two stars, not just in one place on the camera, but over and over thousands of times, reducing the errors in measurement."

The team's goal is to further reduce the uncertainty by using data from Hubble and the European Space Agency's Gaia space observatory, which will measure the positions and distances of stars with unprecedented precision. "This precision is what it will take to diagnose the cause of this discrepancy," Casertano said.

The team's results have been accepted for publication by The Astrophysical Journal:
http://iopscience.iop.org/journal/0004-637X

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

For more about Hubble, visit:

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

For additional imagery to this story, visit: https://media.stsci.edu/news_release/news/2018-12

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Karl Hille/Space Telescope Science Institute/Donna Weaver/Ray Villard.

Best regards, Orbiter.ch

Mars Odyssey Observes Martian Moons











NASA - 2001 Mars Odyssey Mission patch.

Feb. 22, 2018


Phobos and Deimos, the moons of Mars, are seen in this movie put together from 19 images taken by the Mars Odyssey orbiter's Thermal Emission Imaging System, or THEMIS, camera. The images were taken in visible-wavelength light. THEMIS also recorded thermal-infrared imagery in the same scan.

The apparent motion is due to progression of the camera's pointing during the 17-second span of the February 15, 2018, observation, not from motion of the two moons. This was the second observation of Phobos by Mars Odyssey; the first was on September 29, 2017. Researchers have been using THEMIS to examine Mars since early 2002, but the maneuver turning the orbiter around to point the camera at Phobos was developed only recently.

The distance to Phobos from Odyssey during the observation was about 3,489 miles (5,615 kilometers). The distance to Deimos from Odyssey during the observation was about 12,222 miles (19,670 kilometers).

Artist's view of Mars Odyssey spacecraft

THEMIS was developed by and is operated by a team based at Arizona State University, Tempe. NASA's Jet Propulsion Laboratory, Pasadena, California, manages the Mars Odyssey mission for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter and partners in its operation. JPL is a division of Caltech in Pasadena.

Mars Odyssey: http://www.nasa.gov/mission_pages/odyssey/

Image, Animation, Text, Credits: NASA/JPL-Caltech/ASU/SSI.

Best regards, Orbiter.ch

Seven Ways Mars InSight is Different












NASA - InSight Mission logo.

Feb. 22, 2018

Mars in a Minute: What's Inside Mars?

Video above: We know what "The Red Planet" looks like from the outside -- but what's going on under the surface of Mars? Find out more in the 60-second. video from NASA's Jet Propulsion Laboratory.

NASA's Mars InSight lander team is preparing to ship the spacecraft from Lockheed Martin Space in Denver, where it was built and tested, to Vandenberg Air Force Base in California, where it will become the first interplanetary mission to launch from the West Coast. The project is led by NASA’s Jet Propulsion Laboratory in Pasadena, California.

NASA has a long and successful track record at Mars. Since 1965, it has flown by, orbited, landed and roved across the surface of the Red Planet. What can InSight -- planned for launch in May -- do that hasn’t been done before?

- 1 InSight is the first mission to study the deep interior of Mars.

A dictionary definition of "insight" is to see the inner nature of something. InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) will do just that. InSight will take the "vital signs" of Mars: its pulse (seismology), temperature (heat flow), and its reflexes (radio science). It will be the first thorough check-up since the planet formed 4.5 billion years ago.

- 2 InSight will teach us about planets like our own.

InSight's team hopes that by studying the deep interior of Mars, we can learn how other rocky planets form. Earth and Mars were molded from the same primordial stuff more than 4 billion years ago, but then became quite different. Why didn’t they share the same fate?

When it comes to rocky planets, we’ve only studied one in great detail: Earth. By comparing Earth's interior to that of Mars, InSight's team hopes to better understand our solar system. What they learn might even aid the search for Earth-like exoplanets, narrowing down which ones might be able to support life. So while InSight is a Mars mission, it’s also more than a Mars mission.

- 3 InSight will try to detect marsquakes for the first time.

One key way InSight will peer into the Martian interior is by studying motion underground -- what we know as marsquakes. NASA has not attempted to do this kind of science since the Viking mission. Both Viking landers had their seismometers on top of the spacecraft, where they produced noisy data. InSight’s seismometer will be placed directly on the Martian surface, which will provide much cleaner data.

Scientists have seen a lot of evidence suggesting Mars has quakes. But unlike quakes on Earth, which are mostly caused by tectonic plates moving around, marsquakes would be caused by other types of tectonic activity, such as volcanism and cracks forming in the planet's crust. In addition, meteor impacts can create seismic waves, which InSight will try to detect.

Each marsquake would be like a flashbulb that illuminates the structure of the planet’s interior. By studying how seismic waves pass through the different layers of the planet (the crust, mantle and core), scientists can deduce the depths of these layers and what they're made of. In this way, seismology is like taking an X-ray of the interior of Mars.

Scientists think it's likely they'll see between a dozen and a hundred marsquakes over the course of two Earth years. The quakes are likely to be no bigger than a 6.0 on the Richter scale, which would be plenty of energy for revealing secrets about the planet’s interior.

- 4 First interplanetary launch from the West Coast

All of NASA's interplanetary launches to date have been from Florida, in part because the physics of launching off the East Coast are better for journeys to other planets. But InSight will break the mold by launching from Vandenberg Air Force Base in California. It will be the first launch to another planet from the West Coast.

InSight will ride on top of a powerful Atlas V 401 rocket, which allows for a planetary trajectory to Mars from either coast. Vandenberg was ultimately chosen because it had more availability during InSight's launch period.

A whole new region will get to see an interplanetary launch when InSight rockets into the sky. In a clear, pre-dawn sky, the launch may be visible in California from Santa Maria to San Diego.

- 5 First interplanetary CubeSat

The rocket that will loft InSight beyond Earth will also launch a separate NASA technology experiment: two mini-spacecraft called Mars Cube One, or MarCO. These briefcase-sized CubeSats will fly on their own path to Mars behind InSight.


Image above: An artist’s rendition of the InSight lander operating on the surface of Mars. Image Credits: NASA/JPL-Caltech.

Their objective is to relay back InSight data as it enters the Martian atmosphere and lands. It will be a first test of miniaturized CubeSat technology at another planet, which researchers hope can offer new capabilities to future missions.

If successful, the MarCOs could represent a new kind of data relay to Earth. InSight’s success is independent of its CubeSat tag-alongs.

- 6 InSight could teach us how Martian volcanoes were formed.

Mars is home to some impressive volcanic features. That includes Tharsis -- a plateau with some of the biggest volcanoes in the solar system. Heat escaping from deep within the planet drives the formation of these types of features, as well as many others on rocky planets. InSight includes a self-hammering heat probe that will burrow down to 16 feet (5 meters) into the Martian soil to measure the heat flow from the planet's interior for the first time. Combining the rate of heat flow with other InSight data will reveal how energy within the planet drives changes on the surface.

- 7 Mars is a time machine

Studying Mars lets us travel to the ancient past. While Earth and Venus have tectonic systems that have destroyed most of the evidence of their early history, much of the Red Planet has remained static for more than 3 billion years. Because Mars is just one-third the size of Earth and Venus, it contains less energy to power the processes that change a planet's structure. That makes it a fossil planet in many ways, with the secrets of our solar system's early history locked deep inside.

More information about InSight is at: https://mars.nasa.gov/insight

Image (mentioned), Video (JPL), Text, Credits: NASA/Tony Greicius/JPL/Andrew Good.

Greetings, Orbiter.ch

SpaceX - PAZ Mission Success

















SpaceX - PAZ Mission patch.


Feb. 22, 2018

Falcon 9 lift off carrying PAZ & Microsat-2a and 2b

On Thursday, February 22, Falcon 9 successfully launched the PAZ satellite to low-Earth orbit from Space Launch Complex 4 East (SLC-4E) at Vandenberg Air Force Base in California. The instantaneous launch opportunity happened at 6:17 a.m. PST, or 14:17 UTC, and the PAZ satellite was deployed approximately eleven minutes after launch.

PAZ Mission

Paz satellite for Hisdesat of Madrid, Spain. Built by Airbus Defense and Space, Paz carries a radar imaging payload to collect views of Earth for government and commercial customers, along with ship tracking and weather sensors. Two test satellites (Microsat-2a and 2b) for SpaceX’s Starlink broadband network was also launched on the Falcon 9.

PAZ satellite (Credit mentioned on the image)

Falcon 9’s first stage for the PAZ mission previously supported the FORMOSAT-5 mission from SLC-4E in August 2017.

For more information about SpaceX, visit: http://www.spacex.com/

Images, Video, Text, Credits: SpaceX/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.ch

mercredi 21 février 2018

An amateur astronomer hits the jackpot at the "Cosmic Lottery"












Astronomy logo.

February 21, 2018

An Argentine amateur astronomer was able to detect the violent explosion of a star at the end of life, a rare phenomenon and of course unpredictable.

The supernova has been detected in the galaxy NGC 613. Photo Credit: Víctor Buso

One chance in 100 million, the dream of any astronomer: an Argentine amateur has flushed a supernova, the violent explosion of a star at the end of life, reveals a study published Wednesday.

"Professional astronomers have long been looking for such an event," says Alex Filippenko of the American University of Berkeley, co-author of the study. "It's like winning the cosmic lottery," he said in a statement from the University of California.

"The measures of Víctor Buso (amateur astronomer, ed) constitute an unprecedented set of data," said AFP Federico Garcia of the French Atomic Energy Commission, also co-author of the study. It's "exceptional", adds his colleague Alex Filippenko.

On September 20, 2016, Victor Buso from Argentina, who is passionate about the stars, decides to test a new camera on his telescope.

From his home town of Rosario, north of Buenos Aires, he chose, for his first shots, the galaxy NGC 613, located about 80 million light-years from Earth, in the constellation of the Sculptor. Coup de chance: A massive star has just spent its last hours in a cataclysmic explosion known as the supernova.

Galaxy NGC613. Image Credit: Caelum Observatory

The phenomena that accompany the death of a star are very violent because, according to the theory, the matter composing the star is ejected at speeds of several thousand kilometers per second. Due to the incredible amount of energy released, the event shines a lot and can be seen from the Earth.

But the phenomenon is rare and above all unpredictable. Astronomers usually detect it after several days and never at its beginning, as was the chance to do it Victor Buso.

An explosive shock wave

The enlightened amateur gives the alert via the American association of the observers of variable stars (AVVSO), triggering a reaction in chain: a battery of astronomers and physicists point their instruments on the phenomenon. Some will watch the aftermath of the explosion for more than two months.

According to the study published in the British journal Nature, the new data collected allow to better understand the physical structure of the star just before its disappearance and the nature of the explosion.

The team was able to estimate that the initial mass of the star was about 20 times the mass of the Sun.


Animation above: Supernova in NGC 613. Amateur Astronomer Captures Supernova's First Light in NGC 613. Images Credit:Víctor Buso/Animation Credit: Sky & Telescope.

The researchers were also able to observe a spectacular increase in the brightness of the supernova, "in less than half an hour, the object had multiplied its brightness by 3", according to a statement from the French University Paris Diderot.

This could correspond to the emergence of a luminous wave, an explosive shock wave on the surface of the star, already predicted by models but never observed. "The blast wave of the explosion emerges from the stellar surface, having penetrated the supersonic interior of the star. At that moment, a huge quantified light is violently released in a flash of light, "the statement said.

Victor Buso had "only one chance in 10 million or even 100 million" to see this show, says Melina Bersten of the Institute of Astrophysics of La Plata in Argentina, who also participated in the study.

Wikipedia: NGC613: https://en.wikipedia.org/wiki/NGC_613

Animation (mentioned), Images (mentioned), Text, Credits: AFP/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

Station Gets Ready for Crew Swap During Ongoing Human Research









ISS - Expedition 59 Mission patch.

February 21, 2018


Image above: Night over Indian Ocean seen by EarthCam on ISS, speed: 27'576 Km/h, altitude: 416,55 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 February 21, 2018 at 21:39 UTC.

As one crew is packing up for its return back to Earth another crew is training for its launch to the International Space Station. During the month long crew swap activities, human research is still ongoing aboard the orbital laboratory today.

Expedition 54 Commander Alexander Misurkin is getting the Soyuz MS-06 spacecraft ready for its undocking Feb. 27. He and Flight Engineers Joe Acaba and Mark Vande Hei will then take a three-and-a-half-hour ride back to Earth and parachute to a landing in Kazakhstan after 168 days in space.


Image above: A docked Russian Progress resupply ship dominates the foreground as Earth’s limb is illuminated during an orbital night pass. Image Credit: NASA.

They will be replaced by three new Expedition 55 station residents who are in Star City, Russia taking final crew qualification exams today. Cosmonaut Oleg Artemyev will command the Soyuz MS-08 spacecraft that will launch March 21 carrying him and NASA astronauts Ricky Arnold and Drew Feustel to the space station two days later.

Today’s research onboard the station is exploring the physiological changes that take place inside the human body while living and working in space. Astronauts Scott Tingle and Norishige Kanai collected blood and urine samples and stowed them in a science freezer for later analysis as part of the Biochemical Profile and Repository studies. Kanai later checked and tested gear that will measure blood flow in the brain for the new Cerebral Autoregulation experiment.

Related links:

Expedition 54: https://www.nasa.gov/mission_pages/station/expeditions/expedition54/index.html

Expedition 55: https://www.nasa.gov/mission_pages/station/expeditions/expedition55/index.html

Biochemical Profile: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=980

Cerebral Autoregulation: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1938

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

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

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

Best regards, Orbiter.ch

Surfing complete









ESA & ROSCOSMOS - ExoMars Mission patch.

21 February 2018

Slowed by skimming through the very top of the upper atmosphere, ESA’s ExoMars has lowered itself into a planet-hugging orbit and is about ready to begin sniffing the Red Planet for methane.

Aerobraking completed

The ExoMars Trace Gas Orbiter arrived at Mars in October 2016 to investigate the potentially biological or geological origin of trace gases in the atmosphere.

It will also serve as a relay, connecting rovers on the surface with their controllers on Earth.

But before any of this could get underway, the spacecraft had to transform its initial, highly elliptical four-day orbit of about 98 000 x 200 km into the final, much lower and circular path at about 400 km.

Terrifically delicate

“Since March 2017, we’ve been conducting a terrifically delicate ‘aerobraking’ campaign, during which we commanded it to dip into the wispy, upper-most tendrils of the atmosphere once per revolution, slowing the craft and lowering its orbit,” says ESA flight director Michel Denis.

Good progress

“This took advantage of the faint drag on the solar wings, steadily transforming the orbit. It’s been a major challenge for the mission teams supported by European industry, but they’ve done an excellent job and we’ve reached our initial goal.

“During some orbits, we were just 103 km above Mars, which is incredibly close.”

The end of this effort came at 17:20 GMT on 20 February, when the craft fired its thrusters for about 16 minutes to raise the closest approach to the surface to about 200 km, well out of the atmosphere. This effectively ended the aerobraking campaign, leaving it in an orbit of about 1050 x 200 km.

Employing interplanetary experience

“We already acquired experience with aerobraking on a test basis at the end of the Venus Express mission, which was not designed for aerobraking, in 2014,” says spacecraft operations manager Peter Schmitz.

“But this is the first time ESA has used the technique to achieve a routine orbit around another planet – and ExoMars was specifically designed for this.”

ExoMars - Trace Gas Orbiter (TGO)

Aerobraking around an alien planet that is, typically, 225 million km away is an incredibly delicate undertaking. The thin upper atmosphere provides only gentle deceleration – at most some 17 mm/s each second. How small is this?

If you braked your car at this rate from an initial speed of 50 km/h to stop at a junction, you’d have to start 6 km in advance.

Venus Express aerobraking 2014

“Aerobraking works only because we spent significant time in the atmosphere during each orbit, and then repeated this over 950 times,” says Michel.

“Over a year, we’ve reduced the speed of the spacecraft by an enormous 3600 km/h, lowering its orbit by the necessary amount.”

Trimming

In the next month, the control team will command the craft through a series of up to 10 orbit-trimming manoeuvres, one every few days, firing its thrusters to adjust the orbit to its final two-hour, circular shape at about 400 km altitude, expected to be achieved around mid-April.

The initial phases of science gathering, in mid-March, will be devoted to checking out the instruments and conducting preliminary observations for calibration and validation. The start of routine science observations should happen around 21 April.

“Then, the craft will be reoriented to keep its camera pointing downwards and its spectrometers towards the Sun, so as to observe the Mars atmosphere, and we can finally begin the long-awaited science phase of the mission,” says Håkan Svedhem, ESA’s project scientist.

Taking stereo images

The main goal is to take a detailed inventory of trace gases, in particular seeking out evidence of methane and other gases that could be signatures of active biological or geological activity.

A suite of four science instruments will make complementary measurements of the atmosphere, surface and subsurface. Its camera will help to characterise features on the surface that may be related to trace-gases sources, such as volcanoes.

It will also look for water-ice hidden just below the surface, which along with potential trace gas sources could guide the choice for future mission landing sites.

Long-distance calls

April will also see the craft test its data-relay capability, a crucial aspect of its mission at Mars.

A NASA-supplied radio relay payload will catch data signals from US rovers on the surface and relay these to ground stations on Earth. Data relaying will get underway on a routine basis later in the summer.

Relaying calls from rovers

Starting in 2021, once ESA’s own ExoMars rover arrives, the orbiter will provide data-relay services for both agencies and for a Russian surface science platform.

ExoMars is a joint endeavour between ESA and Roscosmos.

ESA's ExoMars: http://www.esa.int/Our_Activities/Space_Science/ExoMars

ExoMars in depth:

ExoMars in depth: http://exploration.esa.int/mars/

Mission operations in depth: http://www.esa.int/Our_Activities/Operations/ExoMars_TGO_operations

Related links:

Mars Express: http://www.esa.int/Our_Activities/Space_Science/Mars_Express

Roscosmos: http://en.federalspace.ru/

ExoMars at IKI: http://exomars.cosmos.ru/

Thales Alenia Space: https://www.thalesgroup.com/en/worldwide/space/space

NASA In 2016 ExoMars orbiter (Electra radio): http://mars.nasa.gov/programmissions/missions/future/exomarsorbiter2016/

Where on Mars?: http://whereonmars.co/

ExoMars for broadcasters: http://www.esa.int/esatv/Transmissions/2016/10/ExoMars_at_Mars_live_coverage

Images, Videos, Text, Credits: ESA/C. Carreau/J. Bauer/University of Bern/ATG medialab.

Best regards, Orbiter.ch

Nearly a Decade After Mars Phoenix Landed, Another Look












NASA - Mars Reconnaissance Orbiter (MRO) logo.

February 21, 2018


Animation above: This animation blinks between two images of NASA's Mars Phoenix Lander hardware around the mission's 2008 landing site on far-northern Mars. By late 2017, dust obscures much of what was visible two months after the landing. The lander is near the top; the back shell and parachute near the bottom. Animation credits: NASA/JPL-Caltech/Univ. of Arizona.

A recent view from Mars orbit of the site where NASA's Phoenix Mars mission landed on far-northern Mars nearly a decade ago shows that dust has covered some marks of the landing.

The Phoenix lander itself, plus its back shell and parachute, are still visible in the image taken Dec. 21, 2017, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. But an animated-blink comparison with an image from about two months after the May 25, 2008, landing shows that patches of ground that had been darkened by removal of dust during landing events have become coated with dust again.

Phoenix Mars Lander. Image Credit: NASA

In August 2008, Phoenix completed its three-month mission studying Martian ice, soil and atmosphere. The lander worked for two additional months before reduced sunlight caused energy to become insufficient to keep the lander functioning. The solar-powered robot was not designed to survive through the dark and cold conditions of a Martian arctic winter.

For additional information about the Phoenix mission, visit:

https://www.nasa.gov/mission_pages/phoenix/main/index.html

For additional information about the Mars Reconnaissance Orbiter mission, visit:

https://mars.nasa.gov/mro/

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

Greetings, Orbiter.ch

mardi 20 février 2018

New Study Brings Antarctic Ice Loss Into Sharper Focus











NASA logo.

Feb. 20, 2018


Image above: The flow of Antarctic ice, derived from feature tracking of Landsat imagery. Image Credits: NASA Earth Observatory.

A NASA study based on an innovative technique for crunching torrents of satellite data provides the clearest picture yet of changes in Antarctic ice flow into the ocean. The findings confirm accelerating ice losses from the West Antarctic Ice Sheet and reveal surprisingly steady rates of flow from its much larger neighbor to the east.

The computer-vision technique crunched data from hundreds of thousands of NASA-U.S. Geological Survey Landsat satellite images to produce a high-precision picture of changes in ice-sheet motion.

The new work provides a baseline for future measurement of Antarctic ice changes and can be used to validate numerical ice sheet models that are necessary to make projections of sea level. It also opens the door to faster processing of massive amounts of data.

“We’re entering a new age,” said the study’s lead author, cryospheric researcher Alex Gardner of NASA’s Jet Propulsion Laboratory in Pasadena, California. “When I began working on this project three years ago, there was a single map of ice sheet flow that was made using data collected over 10 years, and it was revolutionary when it was published back in 2011. Now we can map ice flow over nearly the entire continent, every year. With these new data, we can begin to unravel the mechanisms by which the ice flow is speeding up or slowing down in response to changing environmental conditions.”

The innovative approach by Gardner and his international team of scientists largely confirms earlier findings, though with a few unexpected twists.

Among the most significant: a previously unmeasured acceleration of glacier flow into Antarctica’s Getz Ice Shelf, on the southwestern part of the continent -- likely a result of ice-shelf thinning.

Speeding up in the west, steady flow in the east

The research, published in the journal “The Cryosphere,” also identified the fastest speed-up of Antarctic glaciers during the seven-year study period. The glaciers feeding Marguerite Bay, on the western Antarctic Peninsula, increased their rate of flow by 1,300 to 2,600 feet (400 to 800 meters) per year, probably in response to ocean warming.

Perhaps the research team’s biggest discovery, however, was the steady flow of the East Antarctic Ice Sheet. During the study period, from 2008 to 2015, the sheet had essentially no change in its rate of ice discharge -- ice flow into the ocean. While previous research inferred a high level of stability for the ice sheet based on measurements of volume and gravitational change, the lack of any significant change in ice discharge had never been measured directly.

The study also confirmed that the flow of West Antarctica’s Thwaites and Pine Island glaciers into the ocean continues to accelerate, though the rate of acceleration is slowing.

In all, the study found an overall ice discharge for the Antarctic continent of 1,929 gigatons per year in 2015, with an uncertainty of plus or minus 40 gigatons. That represents an increase of 36 gigatons per year, plus or minus 15, since 2008. A gigaton is one billion tons.

The study found that ice flow from West Antarctica -- the Amundsen Sea sector, the Getz Ice Shelf and Marguerite Bay on the western Antarctic Peninsula -- accounted for 89 percent of the increase.

Computer vision

The science team developed software that processed hundreds of thousands of pairs of images of Antarctic glacier movement from Landsats 7 and 8, captured from 2013 to 2015.

These were compared to earlier radar satellite measurements of ice flow to reveal changes since 2008.

“We’re applying computer vision techniques that allow us to rapidly search for matching features between two images, revealing complex patterns of surface motion,” Gardner said.

Instead of researchers comparing small sets of very high-quality images from a limited region to look for subtle changes, the novelty of the new software is that it can track features across hundreds of thousands of images per year -- even those of varying quality or obscured by clouds -- over an entire continent.

“We can now automatically generate maps of ice flow annually -- a whole year -- to see what the whole continent is doing,” Gardner said.

The new Antarctic baseline should help ice sheet modelers better estimate the continent’s contribution to future sea level rise.

“We’ll be able to use this information to target field campaigns, and understand the processes causing these changes,” Gardner said. “Over the next decade, all this is going to lead to rapid improvement in our knowledge of how ice sheets respond to changes in ocean and atmospheric conditions, knowledge that will ultimately help to inform projections of sea level change.”

Related links:

Earth Research Findings: https://www.nasa.gov/subject/7782/earth-research-findings

Climate: https://www.nasa.gov/subject/3127/climate

Ice: https://www.nasa.gov/subject/3132/ice

Image (mentioned), Text, Credits: NASA/Tony Greicius/JPL/Alan Buis/Written by Pat Brennan.

Greetings, Orbiter.ch

Cosmic explosion 10.5 billion years ago




University of Southampton logo.

Feb. 20, 2018

Researchers from Southampton University have spotted the most distant supernova ever discovered. The phenomenon occurred when a massive star ended in a cataclysmic explosion known as the supernova.

A huge 10.5 billion-year-old cosmic explosion: astronomers announce on Tuesday that they have discovered the supernova, an end-of-life star, the most distant ever detected.

Supernova DES16C2nm. Image credits: Mr Smith / DES Collaboration

"DES16C2nm (the name given to this supernova, ed) is extremely distant, extremely brilliant and extremely rare, not the kind of thing that, as an astronomer, one falls on every day," says Mathew Smith, lead author of the study, in a statement from the University of Southampton (UK).

The phenomenon occurred when a massive star coiled in a galaxy far away ended its days in a cataclysmic explosion known as the supernova.

The phenomena that accompany the death of a star are very violent because the material component of the star is ejected at speeds of several thousand kilometers per second. Due to the incredible amount of energy released, the event shines as much as ... 200 million suns and can be seen from Earth.

Astronomers reveal secrets of most distant supernova ever detected. Image Credit: NASA

The light emitted by the celestial phenomenon reached our planet 10.5 billion years after it took place and was detected for the first time in August 2016. Its distance and extreme brightness were then confirmed in October 2017 by three separate telescopes.

The international team of astronomers led by the University of Southampton and the origin of the study published Tuesday in the Astrophysical Journal ranked the youngest among the "super bright supernovas (SLSN)", the class of supernovas the brightest and the rarest. "In addition to being a very exciting discovery, the extreme distance of DES16C2nm gives us a unique insight into the nature of super bright supernovas," says Mathew Smith.

"The ultraviolet light emitted by this supernova tells us about the amount of metal produced in the explosion and the temperature of the explosion itself, two essential information to understand the causes, the engines, of these cosmic explosions", adds -t it.

Southampton University: https://www.southampton.ac.uk/

Super bright supernovas (SLSN): http://www.rochesterastronomy.org/snimages/

Images (mentioned), Text, Credits: AFP/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch