vendredi 22 juin 2018

Chaotic Clouds of Jupiter












NASA - JUNO Mission logo.

June 22, 2018


This image captures swirling cloud belts and tumultuous vortices within Jupiter’s northern hemisphere.

NASA’s Juno spacecraft took this color-enhanced image at 10:23 p.m. PDT on May 23, 2018 (1:23 a.m. EDT on May 24), as the spacecraft performed its 13th close flyby of Jupiter. At the time, Juno was about 9,600 miles (15,500 kilometers) from the planet's cloud tops, above a northern latitude of 56 degrees.

The region seen here is somewhat chaotic and turbulent, given the various swirling cloud formations. In general, the darker cloud material is deeper in Jupiter’s atmosphere, while bright cloud material is high. The bright clouds are most likely ammonia or ammonia and water, mixed with a sprinkling of unknown chemical ingredients.

A bright oval at bottom center stands out in the scene. This feature appears uniformly white in ground-based telescope observations. However, with JunoCam we can observe the fine-scale structure within this weather system, including additional structures within it. There is not significant motion apparent in the interior of this feature; like the Great Red Spot, its winds probably slows down greatly toward the center.

Juno orbiting Jupiter

Citizen scientists Gerald Eichstädt and Seán Doran created this image using data from the spacecraft’s JunoCam imager.

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

More information about Juno is at:

https://www.nasa.gov/juno and http://missionjuno.swri.edu

Image, Animation, Credits: NASA/Tony Greicius/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt /Seán Doran.

Greetings, Orbiter.ch

jeudi 21 juin 2018

Crew Studies How Space Affects Time Perception, Exercise and Eyesight Today












ISS - Expedition 56 Mission patch.

June 21, 2018

Quite a wide variety of science activities took place today aboard the International Space Station exploring time perception, exercise and eyesight. The Expedition 56 crew members also worked on station plumbing, stowed satellite deployer gear and checked out communications gear.

Two-time station resident Alexander Gerst started his morning helping doctors understand how living in space alters time perception and impacts crew performance. Later he strapped himself into an exercise bike and attached electrodes to his chest to monitor his pulmonary function during the workout session.


Image above: This fish-eye lens view from a window on the Cupola shows the U.S. Cygnus commercial space freighter with its cymbal-like Ultra-Flex solar arrays attached to the Unity module. To its right is the Soyuz MS-09 spacecraft docked to the Rassvet module. Image Credit: NASA.

NASA astronauts Ricky Arnold, Drew Feustel and Serena Auñón-Chancellor teamed up for eye exams with an ultrasound device to study microgravity’s effects on eyesight. The scans were downlinked real-time to scientists on Earth observing the retina and optic nerve while monitoring the health of the astronaut’s eyes.

Auñón-Chancellor started her day changing out a filter and valve in the station’s bathroom located in the Tranquility module. She then checked out Wi-Fi gear connected to antennas installed during a March 29 spacewalk after assisting Feustel in the Japanese Kibo lab module. The duo stowed gear after Wednesday’s successful deployment of a satellite to demonstrate space junk clean up.

Arnold was set to install radio frequency tags today to improve tool tracking but that task was postponed till after the Cygnus cargo ship departs July 15. He then moved on to emergency communication tests with control centers around the world before light maintenance work on a 3D manufacturing device.

Related links:

Time perception: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7504

Satellite: https://www.nasa.gov/mission_pages/station/research/experiments/2456.html

Expedition 56: https://www.nasa.gov/mission_pages/station/expeditions/expedition56/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

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

Best regards, Orbiter.ch

Red Nuggets’ Are Galactic Gold for Astronomers












NASA - Chandra X-ray Observatory patch.

June 21, 2018

About a decade ago, astronomers discovered a population of small, but massive galaxies called “red nuggets.” A new study using NASA’s Chandra X-ray Observatory indicates that black holes have squelched star formation in these galaxies and may have used some of the untapped stellar fuel to grow to unusually massive proportions.

Red nuggets were first discovered by the Hubble Space Telescope at great distances from Earth, corresponding to times only about three or four billion years after the Big Bang. They are relics of the first massive galaxies that formed within only one billion years after the Big Bang. Astronomers think they are the ancestors of the giant elliptical galaxies seen in the local Universe. The masses of red nuggets are similar to those of giant elliptical galaxies, but they are only about a fifth of their size.


Image above: Artist's illustration and X-ray image of "red nugget" galaxy Mrk 1216. Image Credits: X-ray: NASA/CXC/MTA-Eötvös University/N. Werner et al., Illustration: NASA/CXC/M. Weiss.

While most red nuggets merged with other galaxies over billions of years, a small number managed to slip through the long history of the cosmos untouched. These unscathed red nuggets represent a golden opportunity to study how the galaxies, and the supermassive black hole at their centers, act over billions of years of isolation.

For the first time, Chandra has been used to study the hot gas in two of these isolated red nuggets, MRK 1216, and PGC 032673. They are located only 295 million and 344 million light years from Earth respectively, rather than billions of light years for the first known red nuggets. This X-ray emitting hot gas contains the imprint of activity generated by the supermassive black holes in each of the two galaxies.

“These galaxies have existed for 13 billion years without ever interacting with another of its kind,” said Norbert Werner of MTA-Eötvös University Lendület Hot Universe and Astrophysics Research Group in Budapest, Hungary, who led the study. “We are finding that the black holes in these galaxies take over and the result is not good for new stars trying to form.”

Astronomers have long known that the material falling towards black holes can be redirected outward at high speeds due to intense gravitational and magnetic fields. These high-speed jets can tamp down the formation of stars. This happens because the blasts from the vicinity of the black hole provide a powerful source of heat, preventing the galaxy’s hot interstellar gas from cooling enough to allow large numbers of stars to form.

The temperature of the hot gas is higher in the center of the MRK 1216 galaxy compared to its surroundings, showing the effects of recent heating by the black hole. Also, radio emission is observed from the center of the galaxy, a signature of jets from black holes. Finally, the X-ray emission from the vicinity of the black hole is about a hundred million times lower than a theoretical limit on how fast a black hole can grow – called the “Eddington limit” – where the outward pressure of radiation is balanced by the inward pull of gravity. This low level of X-ray emission is typical for black holes producing jets. All these factors provide strong evidence that activity generated by the central supermassive black holes in these red nugget galaxies is suppressing the formation of new stars.

Chandra X-ray Observatory. Animation Credits: NASA/CXC

The black holes and the hot gas may have another connection. The authors suggest that much of the black hole mass may have accumulated from the hot gas surrounding both galaxies. The black holes in both MRK 1216 and PGC 032873 are among the most massive known, with estimated masses of about five billion times that of the Sun, based on optical observations of the speeds of stars near the galaxies’ centers. Furthermore, the masses of the MRK 1216 black hole and possibly the one in PGC 032873 are estimated to be a few percent of the combined masses of all the stars in the central regions of the galaxies, whereas in most galaxies, the ratio is about ten times less.

“Apparently, left to their own devices, black holes can act a bit like a bully,” said co-author Kiran Lakhchaura, also of MTA-Eötvös University.

“Not only do they prevent new stars from forming,” said co-author Massimo Gaspari, an Einstein fellow from Princeton University, “they may also take some of that galactic material and use it to feed themselves,”

In addition, the hot gas in and around PGC 032873 is about ten times fainter than the hot gas around MRK 1216. Because both galaxies appear to have evolved in isolation over the past 13 billion years, this difference might have arisen from more ferocious outbursts from PGC 032873's black hole in the past, which blew most of the hot gas away.

“The Chandra data tell us more about what the long, solitary journey through cosmic time has been like for these red nugget galaxies,” said co-author Rebecca Canning of Stanford University. “Although the galaxies haven’t interacted with others, they’ve shown plenty of inner turmoil.”

A paper describing these results in the latest issue of the Monthly Notices of the Royal Astronomical Society journal and is available online (http://lanl.arxiv.org/abs/1711.09983). NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Read More from NASA's Chandra X-ray Observatory: http://chandra.harvard.edu/photo/2018/mrk1216/

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

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Lee Mohon/Marshall Space Flight Center/Molly Porter/Chandra X-ray Center/Megan Watzke.

Greetings, Orbiter.ch

Rosetta Image Archive Complete












ESA - Rosetta Mission patch.

21 June 2018

All high-resolution images and the underpinning data from Rosetta’s pioneering mission at Comet 67P/Churyumov-Gerasimenko are now available in ESA’s archives, with the last release including the iconic images of finding lander Philae, and Rosetta’s final descent to the comet’s surface.

The images were delivered by the OSIRIS camera team to ESA in May and have now been processed and released in both the Archive Image Browser and the Planetary Science Archive.

Rosetta’s final images

The Archive Image Browser also hosts images captured by the spacecraft’s Navigation Camera, while the Planetary Science Archive contains publicly available data from all eleven science instruments onboard Rosetta – as well as from ESA’s other Solar System exploration missions.

The final batch of high-resolution images from Rosetta’s OSIRIS camera covers the period from late July 2016 to the mission end on 30 September 2016. It brings the total count of images from the narrow- and wide-angle cameras to nearly 100 000 across the spacecraft’s 12 year journey through space, including early flybys of Earth, Mars and two asteroids before arriving at the comet.

 Comet on 2 September 2016 from 2.1 km

The spacecraft’s trajectory around the comet changed progressively during the final two months of the mission, bringing it closer and closer at its nearest point along elliptical orbits. This allowed some spectacular images to be obtained from within just two kilometres of the surface, highlighting the contrasts in exquisite detail between the smooth and dusty terrain, and more consolidated, fractured comet material.

One particularly memorable sets of images captured in this period were those of Rosetta’s lander Philae following the painstaking effort over the previous years to determine its location. With Rosetta flying so close, challenging conditions associated with the dust and gas escaping from the comet, along with the topography of the local terrain, caused problems with getting the best line-of-sight view of Philae’s expected location, but the winning shot was finally captured just weeks before the mission end.

Can you spot Philae in this image?

In the mission’s last hours as Rosetta moved even closer towards the surface of the comet, it scanned across an ancient pit and finally sent back images showing what would become its resting place. Even after the spacecraft was silent, the team were able to reconstruct a last image from the final telemetry packets sent back when Rosetta was within about 20 m of the surface.

“Having all the images finally archived to be shared with the world is a wonderful feeling,” says Holger Sierks, principal investigator of the camera. “We are also pleased to announce that all OSIRIS images are now available under a Creative Commons license.”

Interview with Rosetta’s camera team

“The final set of images supplements the rich treasure chest of data that the scientific community are already delving into in order to really understand this comet from all perspectives – not just from images but also from the gas, dust and plasma angle – and to explore the role of comets in general in our ideas of Solar System formation,” says Matt Taylor, ESA’s Rosetta project scientist. “There are certainly plenty of mysteries, and plenty still to discover.”

Notes for editors:

The OSIRIS images are released under the Creative Commons Attribution-ShareAlike 4.0 (CC BY-SA 4.0) license. To view a copy of this license, please visit https://creativecommons.org/licenses/by-sa/4.0/

Related links:

Archive Image Browser: http://imagearchives.esac.esa.int/

Planetary Science Archive: https://archives.esac.esa.int/psa/#!Home%20View

Creative Commons: https://creativecommons.org/licenses/by-sa/4.0/?

ESA Rosetta: http://www.esa.int/Our_Activities/Space_Science/Rosetta

Frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions

End of mission FAQ: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_s_grand_finale_frequently_asked_questions

Images, Videos, Text, Credits: ESA/Markus Bauer/Matt Taylor/Max Planck Institute for Solar System Research in Göttingen, Germany/Holger Sierks/ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA (CC BY-SA 4.0).

Best regards, Orbiter.ch

Hubble proves Einstein correct on galactic scales












ESA - Hubble Space Telescope logo.

21 June 2018

Most precise test of general relativity outside the Milky Way

Image of ESO 325-G004

An international team of astronomers using the NASA/ESA Hubble Space Telescope and the European Southern Observatory’s Very Large Telescope has made the most precise test of general relativity yet outside our Milky Way. The nearby galaxy ESO 325-G004 acts as a strong gravitational lens, distorting light from a distant galaxy behind it to create an Einstein ring around its centre. By comparing the mass of ESO 325-G004 with the curvature of space around it, the astronomers found that gravity on these astronomical length-scales behaves as predicted by general relativity. This rules out some alternative theories of gravity.

How gravitational lensing acts as a magnifying glass — diagram

Using the NASA/ESA Hubble Space Telescope and European Southern Observatory’s Very Large Telescope (VLT), a team led by Thomas Collett (University of Portsmouth, UK), was able to perform the most precise test of general relativity outside the Milky Way to date.

Two methods of measuring the mass of a galaxy

The theory of general relativity predicts that objects deform spacetime, causing any light that passes by to be deflected and resulting in a phenomenon known as gravitational lensing. This effect is only noticeable for very massive objects. A few hundred strong gravitational lenses are known, but most are too distant to precisely measure their mass. However, the elliptical galaxy ESO 325-G004 is amongst the closest lenses at just 450 million light-years from Earth.

Hubble illuminates cluster of diverse galaxies

Using the MUSE instrument on the VLT the team calculated the mass of ESO 325-G004 by measuring the movement of stars within it. Using Hubble the scientists were able to observe an Einstein ring resulting from light from a distant galaxy being distorted by the intervening ESO 325-G004. Studying the ring allowed the astronomers to measure how light, and therefore spacetime, is being distorted by the huge mass of ESO 325-G004.

Artist’s impression of massive object distorting spacetime

Collett comments: “We know the mass of the foreground galaxy from MUSE and we measured the amount of gravitational lensing we see from Hubble. We then compared these two ways to measure the strength of gravity — and the result was just what general relativity predicts, with an uncertainty of only nine percent. This is the most precise test of general relativity outside the Milky Way to date. And this using just one galaxy!”

Pan across ESO 325-G004

General relativity has been tested with exquisite accuracy on Solar System scales, and the motions of stars around the black hole at the centre of the Milky Way are under detailed study, but previously there had been no precise tests on larger astronomical scales. Testing the long range properties of gravity is vital to validate our current cosmological model.

Interview with Thomas Collett about the research

These findings may have important implications for models of gravity alternative to general relativity. These alternative theories predict that the effects of gravity on the curvature of spacetime are “scale dependent”. This means that gravity should behave differently across astronomical length-scales from the way it behaves on the smaller scales of the Solar System. Collett and his team found that this is unlikely to be true unless these differences only occur on length scales larger than 6000 light-years.

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

“The Universe is an amazing place providing such lenses which we can use as our laboratories,” adds team member Bob Nichol (University of Portsmouth). “It is so satisfying to use the best telescopes in the world to challenge Einstein, only to find out how right he was.”

More information:

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

This research was presented in a paper entitled “A precise extragalactic test of General Relativity” by Collett et al., to appear in the journal Science.

The international team is comprised of: Thomas E. Collett (Institute of Cosmology and Gravitation, University of Portsmouth, UK), Lindsay J. Oldham (Institute of Astronomy, University of Cambridge, UK, and Harvard College, Harvard-Smithsonian Center for Astrophysics, USA), Russell Smith (Centre for Extragalactic Astronomy, University of Durham, UK), Matthew W. Auger (Institute of Astronomy, University of Cambridge, UK), Kyle B. Westfall (ICG, Portsmouth, UK, and University of California, Santa Cruz, USA), David Bacon (ICG, Portsmouth, UK), Robert C. Nichol (ICG, Portsmouth, UK), Karen L. Masters (ICG, Portsmouth, UK), Kazuya Koyama (ICG, Portsmouth, UK) and Remco van den Bosch (Max Planck Institute for Astronomy, Garching, Germany).

Links:

Hubblecast 110 Light: New test of Einstein’s general relativity:
https://www.spacetelescope.org/videos/heic1812a/

Science paper: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1812/heic1812a.pdf

ESO release: http://eso.org/public/news/eso1819

Hubblesite release: http://hubblesite.org/news_release/news/2018-27

NASA/ESA Hubble Space Telescope: https://www.spacetelescope.org/

European Southern Observatory (ESO): https://www.eso.org/public/

Very Large Telescope (VLT): https://www.eso.org/public/teles-instr/paranal-observatory/vlt/

Images, Animation (mentioned), Text, Credits: ESA/Hubble/Mathias Jäger/University of Portsmouth (UK)/Bob Nichol/Thomas Collett/ESO/M. Kornmesser/NASA/The Hubble Heritage Team (STScI/AURA)/Videos: ESO/L. Calçada/NASA, ESA, and The Hubble Heritage Team (STScI/AURA)/University of Portsmouth (UK).

Best regards, Orbiter.ch

The secret spatial aims of the Swiss army












Swiss Army logo.

June 21, 2018

The army thought for a while to launch its own satellite. The project did not succeed but a "space cell" was born from this failure.

The Swiss army has space projects. To put it into practice, it even set up in 2017 a "space cell", reveals Thursday the RTS (Radio Television Swiss). The latter discovered by investigating the subject that the Department of Defense had been in negotiation with the start-up S3 (Swiss Space Systems) which offered launch satellites at broken prices. Through these discussions, the army planned to acquire its own satellite or, failing that, to obtain images provided by the company's & agencies. Objective: not to buy pictures abroad and thus gain independence.


Army spokesman Daniel Reist says negotiations with S3 have remained "at an early stage". Meanwhile, the company sank into a resounding bankruptcy. But the army did not end its space project so far. It created a "space cell", made up of eleven militia officers, more than half of whom also worked for the S3 start-up.

Related article:

Swiss Space Systems: bankruptcy confirmed
https://orbiterchspacenews.blogspot.com/2017/01/swiss-space-systems-bankruptcy-confirmed.html

Swiss Space Systems unveils small reusable satellite launch system
https://orbiterchspacenews.blogspot.com/2013/03/swiss-space-systems-unveils-small.html

Image, Text, Credits: NXP/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

Prolific Sea-Observing Satellite Turns 10










OSTM Jason-2 Mission logo.

June 21, 2018

An international oceanography satellite that is tracking the ongoing rise in global sea level marks its 10th year in orbit yesterday.

Designed for a three-to-five-year mission, the joint U.S./European Ocean Surface Topography Mission (OSTM) on the Jason-2 satellite has now made more than 47,000 trips around our home planet, measuring sea level change across the globe, observing ocean currents, studying climate phenomena such as El Nino and La Nina, and monitoring the long-term rise in global mean sea level. In January 2016, it was joined in orbit by its follow-on mission, Jason-3. NASA's Jet Propulsion Laboratory in Pasadena, California, manages NASA's portion of both missions.


Image above: Illustration of the U.S./European Ocean Surface Topography Mission (OSTM)/Jason-2 satellite, which marked its 10th year in orbit on June 20. Image Credits: NASA-JPL/Caltech.

In July 2017, Jason-2 began a new science mission when it was maneuvered into a slightly lower orbit. In this new orbit, Jason-2 is collecting data along a series of very closely spaced ground tracks, just 5 miles (8 kilometers) apart. It will take just over a year for Jason-2 to complete one cycle of these new ground tracks, which provide a very accurate and high-resolution estimate of the mean sea surface. The pull of gravity from underwater mountains and other features of the sea floor helps to shape the mean sea surface. These new surface measurements are already being used by scientists to improve maps of the shape and depth of the sea floor, resolving many previously unknown seamounts and other geologic features on the ocean bottom. The new maps will also allow for advances in ocean modeling, naval operations and solid Earth dynamics.

Jason-2 data from the new orbit are used by operational agencies to provide societal and strategic benefits, such as real-time information used for deriving ocean currents; improving marine, fishery and naval operations; and calculating tropical cyclone heat potential to improve forecasts of the intensity of tropical hurricanes and cyclones.

"Along with Jason-3, Jason-2 has extended the record of global sea level rise into a third decade," said Glenn Shirtliffe, Jason-2 project manager at JPL.

NASA is currently working with its partners -- the European Space Agency, the National Oceanic and Atmospheric Administration, the Centre National d'etudes Spatiales and the European Organisation for the Exploitation of Meteorological Satellites -- on future generations of satellite altimeters. The instruments are projected for launch in the next decade. They include the Sentinel-6/Jason Continuity of Service (Jason-CS) and Surface Water and Ocean Topography (SWOT) missions.


Image above: Latest image from OSTM/Jason-2's successor satellite, the U.S./European Jason-3, showing sea surface height with respect to the seasonal cycle and the long-term trend. Blue/magenta colors indicate lower-than-normal sea levels, while yellow/red colors indicate higher-than-normal sea levels. Image Credits: NASA/JPL-Caltech.

"In addition to measuring ocean circulation and revealing the ocean's role in Earth's climate, Jason-2 and Jason-3 measure the rise in global sea level caused by global warming," said Josh Willis, JPL oceanographer and NASA's project scientist for both missions. "Melting ice and expanding seawater drive global sea levels higher and higher each year. The rise has become a powerful reminder of how fast humans are changing the climate. These missions keep our finger on the pulse of climate change."

Other significant science results from the Jason-2 mission include studies of ocean circulation; the ties between the ocean and the atmosphere; and improved global climate forecasts and predictions.

"The 10th anniversary of the launch of Jason-2 is also a landmark in the development of operational oceanography, as this was the first Jason mission involving two operational agencies, EUMETSAT and NOAA," said EUMETSAT Director-General Alain Ratier. "This paved the way for the transition from highly successful research missions to an operational altimeter system, which has now turned to reality with Jason-3, Jason-CS/Sentinel-6 and Sentinel-3 providing data until 2030."

"After 10 years of excellent service, we're excited that Jason-2 is continuing to help forecast hurricane intensity and monitor winds and waves, while taking on a new mission of mapping unexplored parts of the ocean," said Eric Leuliette, NOAA's Jason program and project scientist.

For more information on Jason-2 and other satellite altimetry missions, visit:

http://sealevel.jpl.nasa.gov/ and https://www.aviso.altimetry.fr/en/missions/current-missions/jason-2.html

OSTM/Jason-2 is a joint satellite mission operated by CNES, EUMETSAT, NOAA and NASA.

Images (mentioned), Text, Credits: NASA/JPL/Alan Buis.

Greetings, Orbiter.ch