samedi 30 mai 2015

Lifts off from China for Solar Impulse 2











SolarImpulse - Around the World patch.


May 30, 2015

The revolutionary aircraft Solar Impulse 2 took off from China in the night from Saturday to Sunday and headed to Hawaii, to the most dangerous stage of its world tour.


Image Above: The start of the 7th stage of the world tour of Solar Impulse 2, the longest with 8172 km, has again been postponed due to unsafe weather conditions. No new date has been set.

The Swiss pilot André Borschberg will take six days and nights in a row only to commands.

Powered by solar energy alone, the aircraft took off at 2:40 local time Sunday (8:40 p.m. Saturday in Switzerland), from the eastern city of Nanjing where he was confined since April 21. His departure had been postponed several times due to adverse weather, including last Tuesday because of cloud cover over Nanking and the Sea of ​​Japan.

Never Solar Impulse has 2 flew over an ocean or only stayed in the air more than 24 hours: that's how this Pacific crossing is a technological challenge and a historic aviation feat.

62 years old, André Borschberg will have to keep a distance of 8,500 kilometers. A performance that will intersect only brief sleep twenty minutes. His seat, he can not leave, is equipped with a toilet system.

Solar Imapulse 2 lift off from China to Hawaii

Journey without coffee

Every day, the driver will face the Himalayan altitudes around 28,000 feet (8400 meters) and 55 degree temperature variations in the unpressurized cabin seater Solar Impulse 2.

"How will I live in this tiny environment by climbing Everest every day, passing from winter to summer every day due to temperature changes, in just 20 minutes resting me every time?" he was asked in a recent interview with AFP. For this journey, no coffee provided: "It helps a few hours, but then it is negative," he said.

Different anticipated problems

In case of serious failure in flight, the Swiss will parachute into the ocean, hundreds of kilometers from help. No vessel may in effect to track the device, which will fly at a maximum speed of 90 km / h at low altitude and 140 km / h in the upper layers.

But the hypothesis of his own death leaves marble this engineer by training, "I do not see this as risky, because we have worked long on various issues," he confided. "If we lose an engine, you can fly with the other three, for example."

"In the worst case, we have a parachute, a life raft and knows how to use. Obviously, we hope we will not have to do it, "said the pilot.

video
Solar Impulse 2 takes off for 5-day non-stop flight across the Pacific

Promote solar energy

2 Solar Impulse, whose wings are covered with more than 17,000 photovoltaic cells, left on March 9 in Abu Dhabi (United Arab Emirates) for a world tour to promote the use of renewable energy, and in particular the solar energy. He then made a stop in Oman, India, Burma and China, alternately piloted by André Borschberg and his partner in this project, Swiss explorer Bertrand Piccard.

"This first ocean crossing will be unprecedented in the history of aviation. But it is a way (to promote solar energy), not an end in itself, "tweeted Mr Borschberg Saturday within hours of takeoff.

For more information and Following The flight live on the Internet, visit: http://www.solarimpulse.com/leg-7-from-Nanjing-to-Hawaii

Images, Video, Text, Credits: SolarImpulse/ATS/RT/Orbiter.ch Aerospace.

Best regards, Orbiter.ch

vendredi 29 mai 2015

Major work to ready the LHC experiments for Run 2












CERN - European Organization for Nuclear Research logo.

29 May 2015

Next week, the experiments at the Large Hadron Collider (LHC) will be back in action, taking data for the accelerator's second run. The detectors were shut down two years ago for maintenance and refurbishment in preparation for collisions at the higher energy of 13 teraelectronvolts (TeV).


Image above: A magnet is lowered through the ALICE cavern for work on the Large Hadron Collider during Long Shutdown 1 (Image: Maximilien Brice/CERN).

Long Shutdown 1 (LS1) saw hundreds of collaboration members working in and around the experiment caverns on improvements to the detectors. Four of these detectors – ALICE, ATLAS, CMS and LHCb – are enormous, sophisticated machines measuring up to 40 metres long and 20 metres long and made up of dozens of subdetectors, themselves composed of millions of sensitive sensors. Each subdetector is designed to determine the characteristics of one or more types of particle emerging from the particle collisions. These subdetectors include trackers, which reveal the paths of charged particles, and calorimeters, which measure the energy of some particles. All the data collected is grouped and analysed with a view to understanding what happened at the moment of collision. During the second run, up to one billion proton collisions could occur every second in the detectors. Most of the collisions do not yield interesting results and given the enormous quantities of data generated, it can’t all be logged. The trigger system therefore sorts the collisions, keeping just the most interesting events – several hundred per second. The data-acquisition system then records the data and sends it to the Worldwide LHC Computing Grid to be analysed by physicists. During the long shutdown, all these systems were verified and some were renovated or upgraded. Below is an overview of the main work projects that took place in the detector caverns ahead of the big restart.

ALICE


Image above: The installation of the di-jet calorimeter, which improves ALICE’s ability to detect electrons, positrons and photons (Image: Maximilien Brice/CERN).

This experiment, which studies quark-gluon plasma – the matter present in the first moments of the universe's existence – made improvements to most of its 19 subdetectors. One of these was the electromagnetic calorimeter, which measures the energy of the electrons, positrons and photons produced by the collisions. Its range of detection was extended with the addition of the new di-jet calorimeter. Modules were also added to other subdetectors, and tens of kilometres of cables were replaced as part of a complete overhaul of the electrical infrastructure. In terms of computing, ALICE doubled its data-logging capacity with improvements to the trigger and data-acquisition systems carried out by the collaboration’s IT experts.

video
Flying over ALICE

Video above: Timelapse showing work on ALICE during the long shutdown (Video: ALICE).

ATLAS


Image above: Installation of a new layer of pixels in the ATLAS tracker (Image: Claudia Marcelloni/CERN).

The ATLAS detector can now see even better, thanks to a fourth layer of pixels in its pixel tracker, the subdetector closest to the collisions and whose function is to reconstruct the particle trajectories. Improvements were also made to the muon detectors and calorimeters, as well as to the entire basic infrastructure (including the electrical power supply and the cooling systems). Sections of the beam pipe, in which the protons circulate and collide, were replaced to reduce the background noise in the detector. With new, more efficient trigger and data-acquisition systems, ATLAS is ready to log more data than before: it will be capable of recording a thousand events every second – more than double its capacity during Run 1. In addition, an improvement plan to upgrade the simulation, reconstruction and data-analysis software used by physicists to conduct their research was carried out.

video
Fast Forward to Physics

Video above: Timelapse showing work at the ATLAS experiment during Long Shutdown 1 (Video: ATLAS).

CMS


Image above: The installation of the new pixel luminosity telescope in the CMS detector (Image: Maximilien Brice/CERN).

The CMS collaboration carried out important work on its tracker so that it can function at lower temperatures: it was fitted with a new leak-tightness system and a refurbished cooling system. The central section of the beam tube, where the collisions take place, was replaced with a tube of a smaller diameter to allow a new pixel tracker to be installed during the next long shutdown. A brand-new subdetector, the pixel luminosity telescope, was installed on either side of the detector and will enhance the experiment’s ability to measure luminosity (a measure of the number of collisions produced in the experiment). New muon chambers were installed and the hadron calorimeter, which measures the energy of particles containing quarks, was fitted with upgraded photodetectors. Last but not least, the trigger system was improved and the software and computing systems underwent a significant overhaul to reduce the time needed to produce analysis datasets.

LHCb


Image above: The reinstallation of the beam pipe in the LHCb detector (Image: LHCb).

LHCb, the experiment that investigates beauty particles, added a HeRSChel detector along the beam line in order to identify rare processes in which particles are observed inside the detector but not along the beam line itself. The experiment’s beam pipe was also replaced, as was the pipe’s supporting structure, which is now lighter and more “transparent”. The experiments are constantly striving to achieve transparency as the detectors must detect without influencing the results, for example by intercepting particles that they're not supposed to stop or by altering the trajectories.

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

- More information about the LS1 in the experiments: http://press.web.cern.ch/backgrounders/lhc-season-2-major-work-experiments-run-2

- More information about the big questions that the LHC experiments are tackling, read “New frontiers” and follow the scientists at the forefront of particle physics:

https://press.web.cern.ch/backgrounders/lhc-season-2-new-frontiers-physics

http://home.web.cern.ch/about/updates/2015/05/lhc-season-2-follow-people-frontiers-physics

Related links:

Large Hadron Collider (LHC): http://home.web.cern.ch/topics/large-hadron-collider

ALICE experiments: http://home.web.cern.ch/about/experiments/alice

ATLAS experiments: http://home.web.cern.ch/about/experiments/atlas

CMS experiments: http://home.web.cern.ch/about/experiments/cms

LHCb experiments: http://home.web.cern.ch/about/experiments/lhcb

Worldwide LHC Computing Grid: http://home.web.cern.ch/about/computing/worldwide-lhc-computing-grid

For more information about the European Organization for Nuclear Research (CERN), visit: http://home.web.cern.ch/

Images (mentioned), Videos (mentioned), Text, Credits: CERN/Corinne Pralavorio.

Greetings, Orbiter.ch

Blue Aurorae in Mars’ Sky Visible to the Naked Eye














NASA - MAVEN Mission logo / ESA - Mars Express Mission patch.

May 29, 2015

For the first time, an international team of scientists from NASA, the Institute of Planetology and Astrophysics of Grenoble (IPAG), the European Space Agency and Aalto University in Finland, have predicted that colorful, glowing aurorae can be seen by the naked eye on a terrestrial planet other than Earth — Mars.


Image above: The Planeterella sphere simulates a magnetized planet with an atmosphere of CO2 and bombarded by the solar wind. Blue aurorae develop according to its magnetic field configuration. Image Credits: D. Bernard/IPAG — CNRS.

Visible Martian aurorae seemed possible after the SPICAM imaging instrument on-board the ESA satellite Mars Express spotted aurorae from space in 2005. Those observations were confirmed in March 2015 by the NASA-led MAVEN mission, which completed 1,000 orbits around the red planet on April 6, 2015.

Through laboratory experiments and a physical numerical model developed at NASA and IPAG, the study shows that, on Mars, aurorae also occur in the visible range. The most intense color is deep blue. As on Earth, green and red colors are also present. Several times during a solar cycle, after intense solar eruptions, these lights are bright enough to be seen with the naked eye.

Aurorae occur when charged solar particles reach local magnetic field lines, where they enter the planetary atmosphere and excite its atoms and molecules. As they deactivate, the particles produce light emission. On Earth, aurorae are essentially green or red (excitation of atomic oxygen), but even blue-purple (excitation of ionized molecular nitrogen) can be seen.

At the beginning of Mars’ existence and up until 3.5 billion years ago, the red planet hosted a global magnetic field. Although this global field somehow shut down, local spots of increased magnetic fields, called crustal magnetic anomalies, still remain in Mars' surface. These anomalies are concentrated in the southern hemisphere, where aurorae are predicted to occur.

It is predicted that an astronaut walking on the red soil of the planet could look up to see the southern night sky glow blue, with red and green hues.


Image above: This is an artist interpretation of what aurorae may look like close to magnetic anomalies on Mars. Image Credits: NASA/JPL-Caltech/MSSS and CSW/DB.

Perhaps NASA astronauts who plan to make their way towards the Mars’ surface by the 2030s aboard Orion will be the first to provide first-hand confirmation of the prediction. And to think, Mars’ southern lights could eventually become as much of a draw to aurorae admirers as Earth’s northern lights.

“Our planetary research gives us good insight on physics in the Martian atmosphere — how it evolved, why Mars’ mass is different than Earth’s,” said Guillaume Gronoff, a research scientist at NASA’s Langley Research Center who helped to lead the study. “It helps us to better understand planetary atmosphere emissions, ultimately helping us to discover habitable planets.”

The Planeterella:

The Planeterella simulates aurorae using a magnetic field, charged particles and a sphere. For this study, they replaced the terrestrial atmospheric gas with CO2, the major component of the Martian atmosphere, and then created a discharge in a vacuum similar to Mars’ upper atmosphere.  There are seventeen Planeterellas worldwide. One is located at NASA Langley’s official Visitors Center — the Virginia Air and Space Center in Hampton, Va. — where Guillaume occasionally exhibits the simulation.

Related links:

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

NASA MAVEN mission: http://www.nasa.gov/mission_pages/maven/main/index.html

Images, Text, Credits: NASA Langley Research Center/Denise Lineberry​/Samuel McDonald. Prediction of blue, red and green aurorae at Mars by J. Lilensten, D. Bernard, M. Barthélemy, G. Gronoff, C. Simon Wedlund, A. Opitz, Planetary and Space Science, May 2015, PII : S0032-0633(15)00130-0, DOI : 10.1016/j.pss.2015.04.015.

Best regards, Orbiter.ch

Hubble Peers into the Most Crowded Place in the Milky Way

ESA - Hubble Space Telescope patch.

May 29, 2015


This NASA/ESA Hubble Space Telescope image presents the Arches Cluster, the densest known star cluster in the Milky Way. It is located about 25,000 light-years from Earth in the constellation of Sagittarius (The Archer), close to the heart of our galaxy, the Milky Way. It is, like its neighbor the Quintuplet Cluster, a fairly young astronomical object at between two and four million years old.

The Arches cluster is so dense that in a region with a radius equal to the distance between the sun and its nearest star there would be over 100,000 stars! At least 150 stars within the cluster are among the brightest ever discovered in the Milky Way. These stars are so bright and massive that they will burn their fuel within a short time (on a cosmological scale that means just a few million years). Then they will die in spectacular supernova explosions. Due to the short lifetime of the stars in the cluster the gas between the stars contains an unusually high amount of heavier elements, which were produced by earlier generations of stars.

video
Hubble over sunrise

Despite its brightness the Arches Cluster cannot be seen with the naked eye. The visible light from the cluster is completely obscured by gigantic clouds of dust in this region. To make the cluster visible astronomers have to use detectors which can collect light from the X-ray, infrared, and radio bands, as these wavelengths can pass through the dust clouds. This observation shows the Arches Cluster in the infrared and demonstrates the leap in Hubble’s performance since its 1999 image of same object.

For more images and information about Hubble Space Telescope, visit:
http://www.spacetelescope.org/ and http://hubblesite.org/

Image, Video, Credits: NASA/ESA, Text credit: European Space Agency (ESA).

Cheers, Orbiter.ch

Dawn Spirals Closer to Ceres, Returns a New View












NASA - Dawn Mission patch.

May 29, 2015


Image above: A new view of Ceres' surface shows finer details coming into view as NASA's Dawn spacecraft spirals down to increasingly lower orbits. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

A new view of Ceres, taken by NASA's Dawn spacecraft on May 23, shows finer detail is becoming visible on the dwarf planet. The spacecraft snapped the image at a distance of 3,200 miles (5,100 kilometers) with a resolution of 1,600 feet (480 meters) per pixel. The image is part of a sequence taken for navigational purposes.

Image is available at: http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA19065

After transmitting these images to Earth on May 23, Dawn resumed ion-thrusting toward its second mapping orbit. On June 3, Dawn will enter this orbit and spend the rest of the month observing Ceres from 2,700 miles (4,400 kilometers) above the surface. Each orbit during this time will be about three days, allowing the spacecraft to conduct an intensive study of Ceres.


Image above: What's the spot on World Ceres? Can you guess what's creating those unusual bright spots on Ceres? On March 6, NASA's Dawn spacecraft began orbiting Ceres, the largest body in the main asteroid belt between Mars and Jupiter. Even before the spacecraft arrived at the dwarf planet, images revealed mysterious bright spots that captivated scientists and observers alike. Until Dawn gets a closer look over the next few months, it's anyone's guess what those spots could be. So, go ahead! Cast your vote here: http://www.jpl.nasa.gov/dawn/world_ceres/ (Image Credit: NASA).

Dawn is the first mission to visit a dwarf planet, and the first to orbit two distinct solar system targets. It studied the protoplanet Vesta for 14 months in 2011 and 2012, and arrived at Ceres on March 6, 2015.


Animation above: Rotating Ceres and is mysterious two spots. Animation Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Dawn's mission is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit: http://dawn.jpl.nasa.gov/mission

More information about Dawn is available at the following sites: http://dawn.jpl.nasa.gov and http://www.nasa.gov/dawn

Images (mentioned), Text, Credits: NASA/JPL/Elizabeth Landau/Preston Dyches.

Greetings, Orbiter.ch

Cassini Prepares for Last Up-close Look at Hyperion












NASA - Cassini Mission to Saturn patch.

May 29, 2015

NASA / ESA Cassini spacecraft will make its final close approach to Saturn's large, irregularly shaped moon Hyperion on Sunday, May 31.

The Saturn-orbiting spacecraft will pass Hyperion at a distance of about 21,000 miles (34,000 kilometers) at approximately 6:36 a.m. PDT (9:36 a.m. EDT). Mission controllers expect images from the encounter to arrive on Earth within 24 to 48 hours.


Image above: This false-color view of Hyperion was obtained during Cassini's closest flyby of Saturn's odd, tumbling moon on Sept. 26, 2005. Image credit: NASA/JPL-Caltech/SSI.

Mission scientists have hopes of seeing different terrain on Hyperion than the mission has previously explored in detail during the encounter, but this is not guaranteed. Hyperion (168 miles, 270 kilometers across) rotates chaotically, essentially tumbling unpredictably through space as it orbits Saturn. Because of this, it's challenging to target a specific region of the moon's surface, and most of Cassini's previous close approaches have encountered more or less the same familiar side of the craggy moon.

Cassini scientists attribute Hyperion's unusual, sponge-like appearance to the fact that it has an unusually low density for such a large object -- about half that of water. Its low density makes Hyperion quite porous, with weak surface gravity. These characteristics mean impactors tend to compress the surface, rather than excavating it, and most material that is blown off the surface never returns.

Artist's view of Cassini spacecraft around Saturn. Image Credits: NASA/ESA

Cassini's closest-ever Hyperion flyby took place on September 26, 2005, at a distance of 314 miles (505 kilometers).

Cassini's next notable flyby after May 31 is slated for June 16, when the spacecraft will pass 321 miles (516 kilometers) above icy Dione. That flyby will represent the mission's penultimate close approach to that moon. In October, Cassini will make two close flybys of the active moon Enceladus, with its jets of icy spray, coming as close as 30 miles (48 kilometers) in the final pass. In late 2015, the spacecraft will again depart Saturn's equatorial plane -- where moon flybys occur most frequently -- to begin a year-long setup of the mission's daring final year. For its grand finale, Cassini will repeatedly dive through the space between Saturn and its rings.

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. JPL, a division of the California Institute of Technology, manages the mission for NASA's Science Mission Directorate in Washington.

For more information about Cassini, visit:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Images (mentioned), Text, Credits: NASA/JPL/Preston Dyches.

Greetings, Orbiter.ch

jeudi 28 mai 2015

So Far, All Clear: New Horizons Team Completes First Search for Pluto System Hazards












NASA  - New Horizons Mission logo.

May 28, 2015

NASA’s New Horizons team has analyzed the first set of hazard-search images of the Pluto system taken by the spacecraft itself – and so far, all looks clear for the spacecraft’s safe passage.


Images above: This image shows the results of the New Horizons team’s first search for potentially hazardous material around Pluto, conducted May 11-12, 2015, from a range of 47 million miles (76 million kilometers). The image combines 48 10-second exposures, taken with the spacecraft’s Long Range Reconnaissance Imager (LORRI), to offer the most sensitive view yet of the Pluto system. The left panel is a combination of the original images before any processing. The combined glare of Pluto and its large moon Charon in the center of the field, along with the thousands of background stars, overwhelm any faint moons or rings that might pose a threat to the New Horizons spacecraft. The central panel is the same image after extensive processing to remove Pluto and Charon’s glare and most of the background stars, revealing Pluto’s four small moons -- Styx, Nix, Kerberos and Hydra -- as points of light. The right panel overlays the orbits and locations of all five moons, including Charon. Remaining unlabeled spots and blemishes in the processed image are imperfectly removed stars, including variable stars which appear as bright or dark dots. The faint grid pattern is an artifact of the image processing. Celestial north is up in these images.

The observations were made May 11-12 from a range of 47 million miles (76 million kilometers) using the telescopic Long Range Reconnaissance Imager (LORRI) on New Horizons. For these observations, LORRI was instructed to take 144 10-second exposures, designed to allow a highly sensitive search for faint satellites, rings or dust sheets in the system. The mission team is looking carefully for any indications of dust or debris that might threaten New Horizons before the spacecraft’s flight through the Pluto system on July 14; a particle as small as a grain of rice could be fatal.

The observations, downlinked to Earth May 12-15 and processed and analyzed May 12-18, detected Pluto and all five of its known moons, but no rings, new moons, or hazards of any kind. The New Horizons hazard detection team, led by John Spencer of the Southwest Research Institute in Boulder, Colorado, determined that small satellites with about half the brightness of Pluto’s faintest known moon, Styx, could have been detected at this range.  Any undiscovered moons outside the orbit of Pluto’s largest and closest moon, Charon, are thus likely smaller than 3-10 miles (5-15 kilometers) in diameter. If any undiscovered rings are present around Pluto outside Charon’s orbit, they must be very faint or narrow – less than 1,000 miles wide or reflecting less than one 5-millionth of the incoming sunlight.

Artist's view of New Horizons spacecraft at Pluto

The next hazard-search images will be taken May 29-30, and should have about twice the sensitivity of the first batch. The team expects to complete a thorough analysis of the data and report on its results by June 12. The New Horizons team has until July 4 to divert the spacecraft to one of three alternate routes if any dangers are found.

New Horizons is nearly 2.95 billion miles from home, speeding toward Pluto and its moons at just under 750,000 miles per day. The spacecraft is healthy and all systems are operating normally.

The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, designed, built, and operates the New Horizons spacecraft, and manages the mission for NASA’s Science Mission Directorate. Southwest Research Institute, San Antonio and Boulder, Colorado, leads the science team, payload operations and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama.

To view images from New Horizons and learn more about the mission, visit: http://www.nasa.gov/newhorizons

Images, Text, Credits: NASA/Tricia Talbert.

Greetings, Orbiter.ch

NASA Telescopes Set Limits On Spacetime Quantum "Foam"














NASA - Fermi Gamma-ray Space Telescope logo / NASA - Chandra X-ray Observatory patch.

May 28, 2015

A team of scientists has used X-ray and gamma-ray observations of some of the most distant objects in the Universe to better understand the nature of space and time. Their results set limits on the quantum nature, or “foaminess” of spacetime at extremely tiny scales. 

This study combines data from NASA’s Chandra X-ray Observatory and Fermi Gamma-ray Space Telescope along with ground-based gamma-ray observations from the Very Energetic Radiation Imaging Telescope Array (VERITAS).


Image Credit: X-ray: NASA/CXC/FIT/E. Perlman; Illustration: CXC/M. Weiss.

At the smallest scales of distance and duration that we can measure, spacetime – that is, the three dimensions of space plus time – appears to be smooth and structureless. However, certain aspects of quantum mechanics, the highly successful theory scientists have developed to explain the physics of atoms and subatomic particles, predict that spacetime would not be smooth. Rather, it would have a foamy, jittery nature and would consist of many small, ever-changing, regions for which space and time are no longer definite, but fluctuate. 

“One way to think of spacetime foam is if you are flying over the ocean in the airplane, it looks completely smooth. However, if you get low enough you see the waves, and closer still, foam, with tiny bubbles that are constantly fluctuating” said lead author Eric Perlman of the Florida Institute of Technology in Melbourne. “Even stranger, the bubbles are so tiny that even on atomic scales we’re trying to observe them from a very high-flying airplane.”

The predicted scale of spacetime foam is about ten times a billionth of the diameter of a hydrogen atom’s nucleus, so it cannot be detected directly. However, If spacetime does have a foamy structure there are limitations on the accuracy with which distances can be measured because the size of the many quantum bubbles through which light travels will fluctuate. Depending on what model of spacetime is used, these distance uncertainties should accumulate at different rates as light travels travels over the large cosmic distances.

Chandra X-ray Observatory spacecraft. Image Credits: NASA/CXC

The researchers used observations of X-rays and gamma-rays from very distant quasars – luminous sources produced by matter falling towards supermassive black holes – to test models of spacetime foam. The authors predicted that the accumulation of distance uncertainties for light traveling across billions of light years would cause the image quality to degrade so much that the objects would become undetectable. The wavelength where the image disappears should depend on the model of space-time foam used.

Chandra’s X-ray detection of quasars at distances of billions of light years rules out one model, according to which photons diffuse randomly through space-time foam in a manner similar to light diffusing through fog. Detections of distant quasars at shorter, gamma-ray wavelengths with Fermi and even shorter wavelengths with VERITAS demonstrate that a second, so-called holographic model with less diffusion does not work.

“We find that our data can rule out two different models for spacetime foam,” said co-author Jack Ng of the University of North Carolina in Chapel Hill. “We can conclude that spacetime is less foamy that some models predict.”

Fermi Gamma-ray Space Telescope spacecraft. Image Credit: NASA

The X-ray and gamma-ray data show that spacetime is smooth down to distances 1000 times smaller than the nucleus of a hydrogen atom.

These results appear in the May 20th issue of The Astrophysical Journal.
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for the agency’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership managed by the agency's Goddard Space Flight Center in Greenbelt, Maryland. It was developed in collaboration with the U.S. Department of Energy, with contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

VERITAS is operated by a collaboration of more than 100 scientists from 22 different institutions in the United States, Ireland, England and Canada. VERITAS is funded by the U.S. Department of Energy, the U.S. National Science Foundation, the Smithsonian Institution, the Natural Sciences and Engineering Research Council of Canada, the Science Foundation Ireland and the STFC of the U.K.

Read More from NASA's Chandra X-ray Observatory: http://chandra.si.edu/press/15_releases/press_052815.html

For more information about Fermi Gamma-ray Space Telescope, visit: http://fermi.gsfc.nasa.gov/

For more information about Chandra X-ray Observatory, visit: http://chandra.harvard.edu/

Images (mentioned), Text, Credits: NASA/Marshall Space Flight Center/Janet Anderson/Chandra X-ray Center/Megan Watzke/Jennifer Harbaugh.

Greetings, Orbiter.ch

Threading the Milky Way












ESA - Herschel Mission patch.

28 May 2015

Herschel’s view of G49

These three new images of huge filamentary structures of gas and dust from ESA’s Herschel space observatory reveal how matter is distributed across our Galaxy, the Milky Way.

Long and flimsy threads emerge from a twisted mix of material, taking on complex shapes as the gas and dust in them become denser and cooler. Two of them even exhibit a ‘head’ – a brighter clump of matter at the tip of the wispy thread.

With masses of thousands to several tens of thousands times that of our Sun, these are among the most prominent filaments ever observed in the Galaxy. Longer than 100 light-years, they are at most 10 light-years wide, reproducing even at these very large scales the filamentary distribution of matter that Herschel has observed in detail in nearby star-forming regions in the Milky Way.

Herschel’s view of G47

While dust is only a minor ingredient in this cosmic blend, it shines brightly at the far-infrared and submillimetre wavelengths probed by Herschel. This allowed astronomers to reveal for the first time the coolest and densest portions in this tangle, visible in red and yellow in these false-colour images.

The filaments are dotted with brighter clumps: these are cosmic incubators, where the seeds of new generations of stars are taking shape. The blue and violet glow of the fuzzy splotches that embellish the filaments reveals pockets of warmer material, set ablaze by the fierce radiation released by newborn stars still embedded within them.

Herschel’s view of G64

Before Herschel, only two gigantic filaments like these were known, but astronomers have now used data from the observatory to uncover several new ones weaving their way through the spiral arms of the Milky Way. They believe that these are the first structures to form as interstellar matter starts coming together, eventually leading to the formation of stars.

Read more about Herschel’s discovery of filaments: http://sci.esa.int/herschel/55942-herschels-hunt-for-filaments-in-the-milky-way/

More information:

Related scientific papers:

Large scale filaments associated with Milky Way spiral arms, by Ke Wang et al.: http://mnras.oxfordjournals.org/content/450/4/4043.full?sid=3bfc6b90-1d24-4e41-a552-d2b0bf714309

Related links:

ESA Space Science Portal: http://www.esa.int/Our_Activities/Space_Science

Space science image gallery: http://www.esa.int/esa-mmg/mmg.pl?collection=Space+Science&type=I

Herschel: ESA's giant infrared observatory: http://www.esa.int/Our_Activities/Space_Science/Herschel

More about...:

Herschel overview: http://www.esa.int/Our_Activities/Space_Science/Herschel_overview

Online Showcase of Herschel Images OSHI: http://oshi.esa.int/

Herschel: http://www.esa.int/Our_Activities/Operations/Herschel

In depth:

Herschel in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=16

Herschel Science Centre: http://herschel.esac.esa.int/

Images, Text, Credits: ESA/Herschel/PACS/SPIRE/Ke Wang et al. 2015.

Cheers, Orbiter.ch

Merging galaxies break radio silence












ESA - Hubble Space Telescope logo.

28 May 2015

Large Hubble survey confirms link between mergers and supermassive black holes with relativistic jets


Image above: Artist’s illustration of galaxy with jets from a supermassive black hole
Galaxies with relativistic jets.

In the most extensive survey of its kind ever conducted, a team of scientists have found an unambiguous link between the presence of supermassive black holes that power high-speed, radio-signal-emitting jets and the merger history of their host galaxies. Almost all of the galaxies hosting these jets were found to be merging with another galaxy, or to have done so recently. The results lend significant weight to the case for jets being the result of merging black holes and will be presented in the Astrophysical Journal.

Galaxies with relativistic jets

A team of astronomers using the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (WFC3) have conducted a large survey to investigate the relationship between galaxies that have undergone mergers and the activity of the supermassive black holes at their cores.

Radio galaxy 3C 297

The team studied a large selection of galaxies with extremely luminous centres — known as active galactic nuclei (AGNs) — thought to be the result of large quantities of heated matter circling around and being consumed by a supermassive black hole. Whilst most galaxies are thought to host a supermassive black hole, only a small percentage of them are this luminous and fewer still go one step further and form what are known as relativistic jets [1]. The two high-speed jets of plasma move almost with the speed of light and stream out in opposite directions at right angles to the disc of matter surrounding the black hole, extending thousands of light-years into space. The hot material within the jets is also the origin of radio waves.

Radio galaxy 3C 454.1

It is these jets that Marco Chiaberge from the Space Telescope Science Institute, USA (also affiliated with Johns Hopkins University, USA and INAF-IRA, Italy) and his team hoped to confirm were the result of galactic mergers [2].

The team inspected five categories of galaxies for visible signs of recent or ongoing mergers — two types of galaxies with jets, two types of galaxies that had luminous cores but no jets, and a set of regular inactive galaxies [3].

Radio galaxy 3C 356

“The galaxies that host these relativistic jets give out large amounts of radiation at radio wavelengths,” explains Marco. “By using Hubble’s WFC3 camera we found that almost all of the galaxies with large amounts of radio emission, implying the presence of jets, were associated with mergers. However, it was not only the galaxies containing jets that showed evidence of mergers!” [4].

“We found that most merger events in themselves do not actually result in the creation of AGNs with powerful radio emission,” added co-author Roberto Gilli from Osservatorio Astronomico di Bologna, Italy. “About 40% of the other galaxies we looked at had also experienced a merger and yet had failed to produce the spectacular radio emissions and jets of their counterparts.”

video
Artist’s animation of galaxy with jets from a supermassive black hole

Although it is now clear that a galactic merger is almost certainly necessary for a galaxy to host a supermassive black hole with relativistic jets, the team deduce that there must be additional conditions which need to be met. They speculate that the collision of one galaxy with another produces a supermassive black hole with jets when the central black hole is spinning faster — possibly as a result of meeting another black hole of a similar mass — as the excess energy extracted from the black hole’s rotation would power the jets.

video
Fulldome clip showing animation of galaxy with jets from a supermassive black hole

“There are two ways in which mergers are likely to affect the central black hole. The first would be an increase in the amount of gas being driven towards the galaxy’s centre, adding mass to both the black hole and the disc of matter around it,” explains Colin Norman, co-author of the paper. “But this process should affect black holes in all merging galaxies, and yet not all merging galaxies with black holes end up with jets, so it is not enough to explain how these jets come about. The other possibility is that a merger between two massive galaxies causes two black holes of a similar mass to also merge. It could be that a particular breed of merger between two black holes produces a single spinning supermassive black hole, accounting for the production of jets.”

Future observations using both Hubble and ESO’s Atacama Large Millimeter/submillimeter Array (ALMA) are needed to expand the survey set even further and continue to shed light on these complex and powerful processes.

Notes:

[1] Relativistic jets travel at close to the speed of light, making them one of the fastest astronomical objects known.

[2] The new observations used in this research were taken in collaboration with the 3CR-HST team. This international team of astronomers is currently led by Marco Chiaberge and has conducted a series of surveys of radio galaxies and quasars from the 3CR catalogue using the Hubble Space Telescope.

[3] The team compared their observations with the swathes of archival data from Hubble. They directly surveyed twelve very distant radio galaxies and compared the results with data from a large number of galaxies observed during other observing programmes.

[4] Other studies had shown a strong relationship between the merger history of a galaxy and the high levels of radiation at radio wavelengths that suggests the presence of relativistic jets lurking at the galaxy’s centre. However, this survey is much more extensive, and the results very clear, meaning it can now be said with almost certainty that radio-loud AGNs, that is, galaxies with relativistic jets, are the result of galactic mergers.
Notes for editors

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

The international team of astronomers in this study consists of Marco Chiaberge (STScI, USA; Johns Hopkins University, USA; and INAF-IRA, Italy), Roberto Gilli (INAF Osservatorio Astronomico di Bologna, Italy), Jennifer Lotz (STScI, USA) and Colin Norman (Johns Hopkins University, USA; and STScI, USA).

Links

Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

Link to science paper: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1511a.pdf

Images, Videos, Text, Credits: NASA/ESA/Hubble, L. Calçada (ESO)/M. Chiaberge (STScI).

Greetings, Orbiter.ch

Space Station remodelling














ISS - International Space Station patch / ASI - Multi-Purpose Logistics Module (MPLM) patch.

28 May 2015

Moving Leonardo

The International Space Station’s Permanent Multipurpose Module was detached and moved by the main robotic arm to another place on the orbiting laboratory yesterday.

This delicate operation required moving and rotating the 10-tonne Leonardo module from the Unity node to the Tranquility node.

Installing Leonardo

NASA astronauts Terry Virts and Scott Kelly finished unbolting the module, closed the hatch and checked for leaks before the move. They will reopen the hatch at its new location on Tranquility after more leak checks.

video

Video above: International Space Station Module Moved to New Location To Prep For U.S. Commercial Vehicle Traffic.

The change is part of a long line of tasks to allow the Station to berth more visiting spacecraft – Leonardo’s move frees a docking port. Astronauts will install international docking adapters later this year during spacewalks to welcome new types of vessels for astronauts and cargo.

Inside Leonardo

The 16 m-long robot arm was commanded from Earth by mission controllers in Quebec, Canada and Houston, USA, during the three-hour operation.

Leonardo's history

Leonardo was built and designed by Italy’s ASI space agency to transport cargo and equipment to the Space Station inside NASA’s Space Shuttle. Modified to improve its shielding and visibility to visiting craft, it was attached permanently to the Station in 2011 after visiting the outpost seven times.

Leonardo is used for storing cargo bags, spare parts and food. One cargo rack is reserved for astronauts to use as a personal locker for their clothes, personal hygiene material and other belongings.

Leonardo arriving at Station

In exchange for supplying Leonardo, NASA agreed that ASI could send astronauts to the Station. One of these flights is now being filled by ESA’s Samantha Cristoforetti.

The crew might need some time to reorient themselves with the new layout. One of the jobs for the remodelling is to stick new signs on the module’s walls to reflect the new arrangement.

Related links:

Agenzia Spaziale Italiana (ASI): http://www.asi.it/

STS-133 mission (NASA): http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/index.html

NASA Shuttle missions: http://www.nasa.gov/shuttle

Space Station / NASA: http://www.nasa.gov/station

Where is the International Space Station?: http://www.esa.int/Our_Activities/Human_Spaceflight/International_Space_Station/Where_is_the_International_Space_Station

Connect with ESA Astronaut Samantha Cristoforetti: http://samanthacristoforetti.esa.int/

Images Video, Text, Credits: ESA/NASA.

Greetings, Orbiter.ch

mercredi 27 mai 2015

NASA’s New Horizons Sees More Detail as It Draws Closer to Pluto












NASA - New Horizons Mission logo.

May 27, 2015

What a difference 20 million miles makes! Images of Pluto from NASA’s New Horizons spacecraft are growing in scale as the spacecraft approaches its mysterious target. The new images, taken May 8-12 using a powerful telescopic camera and downlinked last week, reveal more detail about Pluto’s complex and high contrast surface.



Images above: These images show Pluto in the latest series of New Horizons Long Range Reconnaissance Imager (LORRI) photos, taken May 8-12, 2015, compared to LORRI images taken one month earlier. In the month between these image sets, New Horizons’ distance to Pluto decreased from 68 million miles (110 million kilometers) to 47 million miles (75 million kilometers), as the spacecraft speeds toward a close encounter with the Pluto system in mid-July. The April images are shown on the left, with the May images on the right. All have been rotated to align Pluto’s rotational axis with the vertical direction (up-down), as depicted schematically in the center panel. Between April and May, Pluto appears to get larger as the spacecraft gets closer, with Pluto’s apparent size increasing by approximately 50 percent. Pluto rotates around its axis every 6.4 Earth days, and these images show the variations in Pluto’s surface features during its rotation. These images are displayed at four times the native LORRI image size, and have been processed using a method called deconvolution, which sharpens the original images to enhance features on Pluto. Deconvolution can occasionally add “false” details, so the finest details in these pictures will need to be confirmed by images taken from closer range in the next few weeks. All of the images are displayed using the same linear brightness scale.

The images were taken from just under 50 million miles (77 million kilometers) away, using the  Long-Range Reconnaissance Imager (LORRI) on New Horizons. Because New Horizons was approximately 20 million miles closer to Pluto in mid-May than in mid-April, the new images contain about twice as many pixels on the object as images made in mid-April.

A technique called image deconvolution sharpens the raw, unprocessed pictures beamed back to Earth. In the April images, New Horizons scientists determined that Pluto has broad surface markings – some bright, some dark – including a bright area at one pole that may be a polar cap. The newer imagery released here shows finer details. Deconvolution can occasionally produce spurious details, so the finest details in these images will need confirmation from images to be made from closer range in coming weeks.

Artist's view of New Horizons spacecraft heading Pluto and Charon

"As New Horizons closes in on Pluto, it's transforming from a point of light to a planetary object of intense interest," said NASA's Director of Planetary Science Jim Green. "We're in for an exciting ride for the next seven weeks."
  
“These new images show us that Pluto’s differing faces are each distinct; likely hinting at what may be very complex surface geology or variations in surface composition from place to place,” added New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado. “These images also continue to support the hypothesis that Pluto has a polar cap whose extent varies with longitude; we’ll be able to make a definitive determination of the polar bright region’s iciness when we get compositional spectroscopy of that region in July.”

The images New Horizons returns will dramatically improve in coming weeks as the spacecraft speeds closer to its July 14 encounter with the Pluto system, covering about 750,000 miles per day.

“By late June the image resolution will be four times better than the images made May 8-12, and by the time of closest approach, we expect to obtain images with more than 5,000 times the current resolution,” said Hal Weaver, the mission’s project scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland.

Following a January 2006 launch, New Horizons is currently about 2.95 billion miles from home; the spacecraft is healthy and all systems are operating normally.

APL designed, built, and operates the New Horizons spacecraft, and manages the mission for NASA’s Science Mission Directorate. SwRI leads the science team, payload operations and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama.

To view images from New Horizons and learn more about the mission, visit: http://www.nasa.gov/newhorizons

Images, Text, Credits: NASA/Tricia Talbert.

Greetings, Orbiter.ch