samedi 14 juillet 2012

New International Crew Launches to Space Station












ROSCOSMOS - Soyuz TMA-05M Mission patch.

07/15/2012


Image above: A Russian Soyuz spacecraft carries the Expedition 32/33 crew to the International Space Station after its July 14, 2012 launch.

July 15 at 06.40 Moscow time from the launch complex area a place Baikonur launch a space rocket (ILV) Soyuz-FG with transport manned spacecraft (TLC) Soyuz TMA-05M (Commander Yuri Malenchenko (Roscosmos), flight engineers : Sanita Williams (NASA), Akihito Hoshide (JAXA).

video
New Expedition 32 Trio Launches to Station


Image above: Everything is nominal, commander of the Soyuz TMA-05M - Yuri Malenchenko (ROSCOSMOS) and Flight Engineer Sanita Williams (NASA). (Screen capture by Orbiter.ch) Credit: NASA TV.

In accordance with the TPC cyclogram flight Soyuz TMA-05M cleanly separated from the third stage of RKN and placed into the desired orbit.

NASA astronaut Suni Williams, Japan Aerospace Exploration Agency astronaut Aki Hoshide and Russian cosmonaut Yuri Malenchenko launched at 10:40 p.m. EDT aboard their Soyuz TMA-05M spacecraft from Baikonur to begin a four-month tour of duty aboard the orbiting complex.

Docking of the Soyuz TMA-05M to the International Space Station is scheduled for July 17.

Read more about Expedition 32: http://www.nasa.gov/mission_pages/station/expeditions/expedition32/index.html

For more information about the International Space Station, visit: http://www.nasa.gov/station

ROSCOSMOS press release: http://www.federalspace.ru/main.php?id=2&nid=19315

Images, Video, Text, Credits: Press Service of the Russian Space Agency (Roscosmos PAO) / ROSCOSMOS TV / NASA TV / Screen capture and text translation: Orbiter.ch.

Greetings, Orbiter.ch

Hubble Sees the Needle Galaxy, Edge-on and Up Close












NASA - Hubble Space Telescope patch.

July 14, 2012


This image snapped by the NASA/ESA Hubble Space Telescope reveals an exquisitely detailed view of part of the disc of the spiral galaxy NGC 4565. This bright galaxy is one of the most famous examples of an edge-on spiral galaxy, oriented perpendicularly to our line of sight so that we see right into its luminous disc. NGC 4565 has been nicknamed the Needle Galaxy because, when seen in full, it appears as a very narrow streak of light on the sky.

The edgewise view into the Needle Galaxy shown here looks very similar to the view we have from our Solar System into the core of the Milky Way. In both cases ribbons of dust block some of the light coming from the galactic disc. To the lower right, the dust stands in even starker contrast against the copious yellow light from the star-filled central regions. NGC 4565’s core is off camera to the lower right.

Studying galaxies like NGC 4565 helps astronomers learn more about our home, the Milky Way. At a distance of only about 40 million light-years, NGC 4565 is relatively close by, and being seen edge-on makes it a particularly useful object for comparative study. As spiral galaxies go, NGC 4565 is a whopper — about a third larger than the Milky Way.

The image was taken with Hubble’s Advanced Camera for Surveys and has a field of view of approximately 3.4 by 3.4 arcminutes.

A version of this image was entered into the Hubble’s Hidden Treasures Image Processing Competition by contestant Josh Barrington.

Links:

ESA / NASA Hubble websites: http://www.spacetelescope.org/ and http://hubblesite.org/

Image, Text, Credit: ESA / NASA.

Best regards, Orbiter.ch

Orbiter Enters, Then Exits, Standby Safe Mode











NASA - Mars Odyssey Mission patch.

July 14, 2012

NASA's Mars Odyssey orbiter experienced about 21 hours in a reduced-activity precautionary status ending at about 10 a.m. PDT (1 p.m. EDT) on Thursday, July 12.

Artist concept of Mars Odyssey. Image credit: NASA/JPL

The orbiter put itself in the precautionary, Earth-pointed status called safe mode, at about 1 p.m. PDT (4 p.m. EDT) on July 11, as it finished a maneuver adjusting, or trimming, its orbit. Odyssey's computer did not reboot, so diagnostic information was subsequently available from the spacecraft's onboard memory. Based on analysis of that information, the mission's controllers sent commands yesterday morning taking Odyssey out of safe mode and reorienting it to point downward at Mars.

"We are on a cautious path to resume Odyssey's science and relay operations soon," said Gaylon McSmith, Odyssey project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We will also be assessing whether another orbit trim maneuver is warranted."

The thruster burn for Wednesday's orbit-trim maneuver lasted 1.5 seconds, as planned, which was shorter than any previous orbit-trim maneuver of the mission's decade at Mars. The spacecraft's onboard capability for maintaining orientation during the burn put unexpectedly high demand on a reaction wheel in the attitude control system, which prompted the change to safe mode.


Video above: Music for the NASA Mission 2001 Mars Odyssey.  Concert conceived and designed by Vangelis at the Temple of Zeus in Athens Hellas ( Greece).

NASA launched the Mars Odyssey spacecraft on April 7, 2001, and it arrived at Mars Oct. 24, 2001. It has worked at Mars longer than any other Mars mission in history. Besides conducting its own scientific observations, it serves as a communication relay for robots on the Martian surface. NASA plans to use Odyssey and the newer Mars Reconnaissance Orbiter as communication relays for the Mars Science Laboratory mission during the landing and Mars-surface operations of its Curiosity rover.

Odyssey is managed by JPL for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built the spacecraft. JPL and Lockheed Martin collaborate on operating the spacecraft. For more about the Mars Odyssey mission, visit: http://www.nasa.gov/mission_pages/odyssey/index.html and http://mars.jpl.nasa.gov/odyssey .

Image, Video, Text, Credits: NASA / JPL / Guy Webster / Youtube.

Cheers, Orbiter.ch

SDO Captures X1.4 Solar Flare on July 12, 2012













NASA - Solar Dynamics Observatory (SDO) patch.

July 14, 2012

video

This movie shows the sun July 11-12, ending with the X1.4 class flare on July 12, 2012. It was captured by NASA’s Solar Dynamics Observatory in the 304 Angstrom wavelength - a wavelength colorized most like the sun. There is also a coronal mass ejection associated with this flare.

video
Multiple Views of X1.4 Solar Flare on July 12, 2012

This video shows the July 12, 2012 X1.4 class solar flare in a variety of wavelength; 131- Teal colored, 335 - blue colored, 171 - yellow colored and finally a combined wavelength view. All video was captured by the Solar Dynamic Observatory's (SDO) AIA instrument.


This image from the Solar Dynamics Observatory shows the sun at 12:45 PM EDT on July 12, 2012 during an X1.4 class flare. The image is captured in the 304 Angstrom wavelength, which is typically colorized in red. Credit: NASA/SDO/AIA.


This image combines two sets of observations of the sun at 10:45 AM EDT, July 12, 2012 from the Solar Dynamics Observatory (SDO) to give an impression of what the sun looked like shortly before it unleashed an X-class flare beginning at 12:11 PM EDT. The image incorporates light in the 171 Angstrom wavelength, which shows off giant loops of solar material overlying the middle of the sun over Active Region 1520 where the flare originated. The second set of observations is called a magnetogram, which highlights magnetic fields on the sun. Together these kinds of observations can help scientists understand the magnetic properties of the sun that lead to giant explosions like flares.

What is a solar flare? What is a coronal mass ejection?

For answers to these and other space weather questions, please visit the Spaceweather Frequently Asked Questions page: http://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html

For more information about SDO Mission, visit: http://sdo.gsfc.nasa.gov/ and http://www.nasa.gov/mission_pages/sdo/main/index.html

Images, Videos, Text, Credit: NASA / SDO / AIA.

Greetings, Orbiter.ch

vendredi 13 juillet 2012

LHC 2012 proton run extended by seven weeks












CERN - European Organization for Nuclear Research logo.

13 July 2012

 The ATLAS detector at the LHC (Image: CERN)

An important piece of news that almost got lost in the excitement of the Higgs update seminar on 4 July is that the 2012 Large Hadron Collider (LHC) proton run is to be extended. On 3 July, a meeting was held between CERN management and representatives from the LHC and experiments to discuss the merits of increasing the data target for this year in the light of the announcement to be made the following day. The conclusion was that an additional seven weeks of running would allow the luminosity goal for the year to be increased from 15 to 20 inverse femtobarns – a measure of accelerator performance equivalent to about 2000 trillion proton collisions – giving the experiments a good supply of data to work on during the LHC's first long shut-down (LS1), and allowing them to make progress in determining the properties of the new particle whose discovery was announced last week.

LHC: The search of the secrets of the Universe

The current LHC schedule foresees proton running reaching a conclusion on 16 October, with a proton-ion run scheduled for November. In the preliminary new schedule, proton running is planned to continue until 16 December, with the proton-ion run starting after the Christmas stop on 18 January and continuing until 10 February. With a final Higgs update for 2012 scheduled to be given to Council during the week of 10 December, an early Christmas present in the form of new insights into the discovery announced last week could be on the cards.

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 20 Member States.

Related link:

Higgs update seminar: http://cdsweb.cern.ch/record/1459565

More information:

    LHC homepage: http://lhc.web.cern.ch/lhc/

    ATLAS: http://atlas.ch/

    CMS: http://cms.web.cern.ch/

Images, Text, Credit: CERN.

Best regards, Orbiter.ch

Outburst












NASA - Chandra X-ray Observatory patch.

July 13, 2012


NASA's Chandra X-ray Observatory has discovered an extraordinary outburst by a black hole in the spiral galaxy M83, located about 15 million light years from Earth. Using Chandra, astronomers found a new ultraluminous X-ray source, or ULX. These objects give off more X-rays than most normal binary systems in which a companion star is in orbit around a neutron star or black hole.

Chandra X-ray Observatory

For more information about Chandra X-ray Observatory Mission, visit: http://www.nasa.gov/mission_pages/chandra/main/index.html

Images, Text, Credit: NASA / CXC / Curtin University / R.Soria et al.

Greetings, Orbiter.ch

jeudi 12 juillet 2012

Space signal demonstrates Galileo interoperability with GPS












ESA - GALILEO Mission logo.

12 July 2012


ESA’s first two Galileo navigation satellites in space have achieved their latest milestone, transmitting dummy signals in a modulation scheme designed to allow full interoperability with the US GPS once operational services start.

“This is an advanced modulation technique that offers robust protection against signal interference and the misleading signal reflections known as ‘multipath’,” said Marco Falcone, Head of Galileo System Services.

First two Galileo IOV satellites

“Significantly, this is also the European version of the Multiplexed Binary Offset Code signal standard agreed with the United States for the interoperability of Galileo and GPS.

“So this transmission helps demonstrate how the two systems will work together in future with no risk of signal interference.” 

The first two Galileo satellites were launched from Europe’s Spaceport in French Guiana into medium orbits on 21 October 2011, and since then have been progressively put through their paces in a series of tests.

These satellites are serving to validate the Galileo system design as well as being fully functional elements of the full 30-strong constellation that will follow.

Galileo CBOC modulation

Four satellites, the minimum number needed to achieve a position fix at user level, will become available later on this year.

This autumn the next two satellites will be launched together from French Guiana.

Once they are commissioned, Galileo will have its operational nucleus complete, able to perform actual ranging when all four satellites are visible from a receiver.

For technical details of the Galileo signal currently being transmitted, see the right-hand link.

Related link:

Public Galileo Open Service Signal In Space Interface Control Document:
http://ec.europa.eu/enterprise/policies/satnav/galileo/open-service/index_en.htm

Images, Text, Credits: ESA / P. Carril.

Cheers, Orbiter.ch

NASA Astronaut Mark Polansky Leaves Agency












NASA patch.

July 12, 2012

NASA astronaut Mark Polansky has left the agency. His last day with NASA was June 30.

Polansky is a veteran of three space shuttle missions. He flew as a pilot on the STS-98 mission in 2001 and served as commander for STS-116 in 2006 and STS-127 in 2009. Polansky ends his NASA career with more than 41 days in space.

"Mark is a remarkably talented individual," said Peggy Whitson, chief of the Astronaut Office. "His skills as an aviator coupled with his engineering expertise were a valuable contribution to our team. We wish him well in his future endeavors."

Astronaut Mark Polansky

A former U.S. Air Force officer, Polansky joined NASA as a research pilot in 1992 and was selected for the astronaut corps in 1996. Before flying in space, Polansky served in multiple technical roles including space shuttle capsule communicator and chief instructor astronaut. His most recent NASA assignment included duties as director of operations at the Gagarin Cosmonaut Training Center in Star City, Russia.

Polansky earned a Bachelor of Science in aeronautical and astronautical engineering and a Master of Science in aeronautics and astronautics from Purdue University, West Lafayette, Ind.

For Polansky's complete biography, visit: http://www.jsc.nasa.gov/Bios/htmlbios/polansky.html

Image, Text, Credit: NASA.

Greetings, Orbiter.ch

mercredi 11 juillet 2012

Hubble Discovers New Pluto Moon












ESA - Hubble Space Telescope logo.

11 July 2012

 Hubble finds fifth moon orbiting Pluto

A team of astronomers using the NASA/ESA Hubble Space Telescope has discovered a fifth moon orbiting the icy dwarf planet Pluto.

Pluto’s new-found moon, visible as a speck of light in Hubble images, is estimated to be irregular in shape and between 10 and 25 kilometres across. It is in a 95 000 kilometre-diameter circular orbit around Pluto that is assumed to lie in the same plane as Pluto’s other known moons.

“The moons form a series of neatly nested orbits, a bit like Russian dolls,” said Mark Showalter of the SETI Institute in Mountain View, USA, leader of the scientific team that discovered the new moon.

Hubble finds fifth moon orbiting Pluto (unlabelled)

The Pluto team is intrigued that such a small planet can have such a complex collection of satellites. The new discovery provides additional clues for unraveling how the Pluto system formed and evolved. The favoured theory is that all the moons are relics of a collision between Pluto and another large Kuiper belt [1] object billions of years ago.

Pluto’s largest moon, Charon, was discovered in 1978. Hubble observations in 2006 uncovered two additional small moons, Nix and Hydra. In 2011 another moon, known as P4, was found in Hubble data.

Provisionally designated S/2012 (134340) 1, or P5, the latest moon was detected in nine separate sets of images taken by Hubble’s Wide Field Camera 3 on 26, 27 and 29 June, and 7 and 9 July 2012.

Hubble in orbit

New Horizons, a NASA space probe, is currently en route to Pluto, with a high-speed flyby scheduled for 2015. It will return the first ever detailed images of the Pluto system, which is so small and distant that even Hubble can barely see the largest features on its surface.

In the years following the New Horizons Pluto flyby, astronomers plan to use the infrared vision of Hubble’s planned successor, the NASA/ESA/CSA James Webb Space Telescope, for follow-up observations. The James Webb Space Telescope will be able to study the surface chemistry of Pluto, its moons, and many other bodies that lie in the distant Kuiper Belt along with Pluto.

Notes:

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

The Pluto team members are M. Showalter (SETI Institute, Mountain View, USA), H.A. Weaver (Applied Physics Laboratory, Johns Hopkins University, Baltimore, USA), and S.A. Stern, A.J. Steffl, and M.W. Buie (Southwest Research Institute, San Antonio, USA).

[1] The Kuiper belt is a region of space in the outer region of the Solar System which contains many small icy objects, and a number of dwarf planets including Pluto.

Links:

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

    NASA release link: http://hubblesite.org/newscenter/archive/releases/2012/32

Images, Text, Credit: NASA / ESA / M. Showalter (SETI Institute).

Greetings, Orbiter.ch

Dark Galaxies of the Early Universe Spotted for the First Time












ESO - European Southern Observatory logo.

11 July 2012

 Dark galaxies spotted for the first time

For the first time, dark galaxies — an early phase of galaxy formation, predicted by theory but unobserved until now — may have been spotted. These objects are essentially gas-rich galaxies without stars. Using ESO’s Very Large Telescope, an international team thinks they have detected these elusive objects by observing them glowing as they are illuminated by a quasar.

Dark galaxies are small, gas-rich galaxies in the early Universe that are very inefficient at forming stars. They are predicted by theories of galaxy formation and are thought to be the building blocks of today’s bright, star-filled galaxies. Astronomers think that they may have fed large galaxies with much of the gas that later formed into the stars that exist today.

Dark galaxies spotted for the first time (annotated)

Because they are essentially devoid of stars, these dark galaxies don’t emit much light, making them very hard to detect.  For years astronomers have been trying to develop new techniques that could confirm the existence of these galaxies. Small absorption dips in the spectra of background sources of light have hinted at their existence. However, this new study marks the first time that such objects have been seen directly.

“Our approach to the problem of detecting a dark galaxy was simply to shine a bright light on it.” explains Simon Lilly (ETH Zurich, Switzerland), co-author of the paper. “We searched for the fluorescent glow of the gas in dark galaxies when they are illuminated by the ultraviolet light from a nearby and very bright quasar. The light from the quasar makes the dark galaxies light up in a process similar to how white clothes are illuminated by ultraviolet lamps in a night club.” [1]

The location of the quasar HE 0109-3518

The team took advantage of the large collecting area and sensitivity of the Very Large Telescope (VLT), and a series of very long exposures, to detect the extremely faint fluorescent glow of the dark galaxies. They used the FORS2 instrument to map a region of the sky around the bright quasar [2] HE 0109-3518, looking for the ultraviolet light that is emitted by hydrogen gas when it is subjected to intense radiation. Because of the expansion of the Universe, this light is actually observed as a shade of violet by the time it reaches the VLT. [3]

“After several years of attempts to detect fluorescent emission from dark galaxies, our results demonstrate the potential of our method to discover and study these fascinating and previously invisible objects,” says Sebastiano Cantalupo (University of California, Santa Cruz), lead author of the study.

Wide-field view of the sky around the quasar HE0109-3518

The team detected almost 100 gaseous objects which lie within a few million light-years of the quasar. After a careful analysis designed to exclude objects where the emission might be powered by internal star-formation in the galaxies, rather than the light from the quasar, they finally narrowed down their search to 12 objects. These are the most convincing identifications of dark galaxies in the early Universe to date.

The astronomers were also able to determine some of the properties of the dark galaxies. They estimate that the mass of the gas in them is about 1 billion times that of the Sun, typical for gas-rich, low-mass galaxies in the early Universe. They were also able to estimate that the star formation efficiency is suppressed by a factor of more than 100 relative to typical star-forming galaxies found at similar stage in cosmic history. [4]

Dark galaxies of the early Universe (cutouts)

“Our observations with the VLT have provided evidence for the existence of compact and isolated dark clouds. With this study, we’ve made a crucial step towards revealing and understanding the obscure early stages of galaxy formation and how galaxies acquired their gas”, concludes Sebastiano Cantalupo.

video
Zooming in on HE 0109-3518

The MUSE integral field spectrograph, which will be commissioned on the VLT in 2013, will be an extremely powerful tool for the study of these objects.

Notes:

[1] Fluorescence is the emission of light by a substance illuminated by a light source. In most cases, the emitted light has longer wavelength than the source light. For instance, fluorescent lamps transform ultraviolet radiation — invisible to us — into optical light. Fluorescence appears naturally in some compounds, such as rocks or minerals but can be also added intentionally as in detergents that contain fluorescent chemicals to make white clothes appear brighter under normal light.

[2] Quasars are very bright, distant galaxies that are believed to be powered by supermassive black holes at their centres. Their brightness makes them powerful beacons that can help to illuminate the surrounding area, probing the era when the first stars and galaxies were forming out of primordial gas.

[3] This emission from hydrogen is known as Lyman-alpha radiation, and is produced when electrons in hydrogen atoms drop from the second-lowest to the lowest energy level. It is a type of ultraviolet light. Because the Universe is expanding, the wavelength of light from objects gets stretched as it passes through space. The further light has to travel, the more its wavelength is stretched. As red is the longest wavelength visible to our eyes, this process is literally a shift in wavelength towards the red end of the spectrum — hence the name ‘redshift’. The quasar HE 0109-3518 is located at a redshift of z = 2.4, and the ultraviolet light from the dark galaxies is shifted into the visible spectrum. A narrow-band filter was specially designed to isolate the specific wavelength of light that the fluorescent emission is redshifted to. The filter was centered at around 414.5 nanometres in order to capture Lyman-alpha emission redshifted by z=2.4 (this corresponds to a shade of violet) and has a bandpass of only 4 nanometres.

[4] The star formation efficiency is the mass of newly formed stars over the mass of gas available to form stars. They found these objects would need more than 100 billion years to convert their gas into stars. This result is in accordance with recent theoretical studies that have suggested that gas-rich low-mass haloes at high redshift may have very low star formation efficiency as a consequence of lower metal content.

More information:

This research was presented in a paper entitled "Detection of dark galaxies and circum-galactic filaments fluorescently illuminated by a quasar at z=2.4", by Cantalupo et al. to appear in Monthly Notices of the Royal Astronomical Society.

The team is composed of Sebastiano Cantalupo (University of California, Santa Cruz, USA), Simon J. Lilly (ETH Zurich, Switzerland) and Martin G. Haehnelt (Kavli Institute for Cosmology, Cambridge, United Kingdom).

The year 2012 marks the 50th anniversary of the founding of the European Southern Observatory (ESO). ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:

    Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1228/eso1228.pdf

    Photos of the VLT: http://www.eso.org/public/images/archive/search/?adv=&subject_name=Very%20Large%20Telescope

    Other images taken with the VLT: http://www.eso.org/public/images/archive/search/?adv=&facility=31

Images, Text, Credits: ESO / Digitized Sky Survey 2 and S. Cantalupo (UCSC) / IAU and Sky & Telescope / ESO / Digitized Sky Survey 2. Acknowledgment: Davide De Martin / Institute for Astronomy, ETH Zurich / Simon J. Lilly / ESO, La Silla, Paranal, E-ELT & Survey Telescopes / Richard Hook / Video: ESO, Digitized Sky Survey 2, Akira Fujii / David Malin Images. Music: Disasterpeace.

Greetings, Orbiter.ch

mardi 10 juillet 2012

Hubble Unmasks Ghost Galaxies












ESA - Hubble Space Telescope logo.

10 July 2012

 Hubble probes ‘ghost’ galaxy

Astronomers have used the NASA/ESA Hubble Space Telescope to study some of the smallest and faintest galaxies in our cosmic neighbourhood. These galaxies are fossils of the early Universe: they have barely changed for 13 billion years. The discovery could help explain the so-called “missing satellite” problem, where only a handful of satellite galaxies have been found around the Milky Way, against the thousands that are predicted by theories.

Astronomers have puzzled over why some extremely faint dwarf galaxies spotted in our Milky Way galaxy’s backyard contain so few stars. The galaxies are thought to be some of the tiniest, oldest, and most pristine galaxies in the Universe. They have been discovered over the past decade by astronomers using automated computer techniques to search through the images of the Sloan Digital Sky Survey. But an international team of astronomers needed the NASA/ESA Hubble Space Telescope to help solve the mystery of why these galaxies are starved of stars, and why so few of them have been found.

Hubble probes ‘ghost’ galaxy

Hubble views of three of these small galaxies, the Hercules, Leo IV and Ursa Major dwarf galaxies, reveal that they all started forming stars more than 13 billion years ago — and then abruptly stopped — all in the first billion years after the Universe was born in the Big Bang. In fact, the extreme age of their stars is similar to Messier 92, the oldest known globular cluster [1] in the Milky Way.

“These galaxies are all ancient and they’re all the same age, so you know something came down like a guillotine and turned off the star formation at the same time in these galaxies,” said Tom Brown of the Space Telescope Science Institute in Baltimore, USA, the study’s leader. “The most likely explanation is a process called reionisation.”

The relic galaxies are evidence for a transitional phase in the early Universe that shut down star-making factories in tiny galaxies. This phase seems to coincide with the time when the first stars burned off a fog of cold hydrogen, a process called reionisation. In this period, which began in the first billion years after the Big Bang, radiation from the first stars knocked electrons off primeval hydrogen atoms, ionising the Universe’s cool hydrogen gas. [2]

Veil lifted on ‘ghost’ galaxy

The same radiation that sparked universal reionisation also appears to have squelched star-making activities in dwarf galaxies, such as those in Brown’s study. The small irregular galaxies were born about 100 million years before reionisation began and had just started to churn out stars at that time. Roughly 2000 light-years wide, these galaxies are the lightweight cousins of the more luminous and higher-mass star-making dwarf galaxies near our Milky Way. Unlike their higher-mass relatives, the puny galaxies were not massive enough to shield themselves from the harsh ultraviolet light. What little gas they had was stripped away as the flood of ultraviolet light rushed through them. Their gas supply depleted, the galaxies could not make new stars.

The discovery could help explain the so-called “missing satellite problem,” where only a few dozen dwarf galaxies have been observed around the Milky Way while the computer simulations predict that thousands should exist. One possible explanation for the low number discovered to date is that there has been very little, or even no star formation in the smallest of these dwarf galaxies, leaving them virtually invisible.

A swarm of dark matter around the Milky Way

The Sloan survey recently uncovered more than a dozen of these galaxies in our cosmic neighbourhood. These have very few stars — only a few hundred or thousand — but a great deal of dark matter, the underlying scaffolding upon which galaxies are built. Normal dwarf galaxies near the Milky Way contain 10 times more dark matter than the ordinary matter that makes up gas and stars, while in these so-called ultra-faint dwarf galaxies, dark matter outweighs ordinary matter by at least a factor of 100. Astronomers think the rest of the sky should contain dozens more of these ultra-faint dwarf galaxies with few stars, and the evidence for squelched star formation in the smallest of these dwarfs suggests that there may be still thousands more with essentially no stars at all.

video
Animated movie traces evolution of stars in dwarf galaxy

“By measuring the star formation histories of the observed dwarfs, Hubble has supported the theoretical explanation for the paucity of such objects, according to which star formation in the smaller clumps would be shut down by reionisation,” said Jason Tumlinson of the Space Telescope Science Institute, a member of the research team.

The results are published in the 1 July issue of The Astrophysical Journal Letters.

Notes:

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

The international team of astronomers in this study consists of T. M. Brown (STScI), J. Tumlinson (STScI), M. Geha (Yale), E. N. Kirby (Cal Tech), D. A. VandenBerg (University of Victoria), R. R. Munoz (University of Chile), J. S. Kalirai (STScI), J. D. Simon (Carnegie Institution), R. J. Avila (STScI), P. Guhathakurta (UCO/Lick), A. Renzini (Osservatorio Astronomico di Padova) and, H. C. Ferguson (STScI)

[1] Globular clusters are tightly-bound spherical collections of up to a few hundred thousand stars. They are known to contain some of the most ancient stars in the Universe. In addition, globular clusters are known to have formed in single events, so all the stars in them have the same age.

[2] The period of reionisation is also the limit for how far telescopes can see: the process is what rendered the Universe’s hydrogen gas transparent to ultraviolet light.

Links:

    Science paper: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1211.pdf

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

Images, Video, Text, Credits: NASA, ESA, and T. Brown, J. Tumlinson (STScI).

Best regards, Orbiter.ch

ESA’s Clean Space targets orbital debris and greener environment





ESA - ESTEC logo.

10 July 2012

Next year’s Hollywood film Gravity features George Clooney stranded in orbit by cascading space junk. The threat is genuine, with debris levels rising steadily. ESA’s new Clean Space initiative is developing methods of preserving near-Earth space – and the terrestrial environment, too.

Responding to public environmental concerns, Clean Space aims to reduce the environmental effect of Europe’s space activities, cutting waste and pollution on Earth and in orbit.

Debris in low-Earth orbit

Industry is contributing to ESA’s draft plans for developing Clean Space technologies: new tools to assess environmental effects, more eco-friendly replacements for materials and techniques, and ways to halt the production of more space debris and bring down existing debris levels. 

ESA Director General Jean-Jacques Dordain emphasises that implementing Clean Space is a major objective of Agenda 2015, the Agency’s upcoming action plan: “If we are convinced that space infrastructure will become more and more essential, then we must transmit the space environment to future generations as we found it, that is, pristine.”

Mr Dordain, ESA Director General

“We can therefore say that Clean Space is not a new programme, but instead a new way of designing all of ESA’s programmes. I would like ESA to become a model agency in this respect.

“We will not succeed alone; we will need everyone’s help. The entire space sector has to be with us.”

ESTEC, ESA’s technical centre in Noordwijk, the Netherlands, hosted a Clean Space workshop in June, jointly organised by ESA and industry body Eurospace.

Earth: cleaning up space projects

On Earth, Clean Space involves evaluating the environmental impact of future space projects, as well as monitoring the likely effects of forthcoming legislation on the space industry – environmental law being an extremely fast-moving field.

Clean Space workshop

Life-cycle assessment will be important for evaluating the environmental effects of space technologies, from their initial design and manufacture to their end-of-life.

In the workshop, Environmental consultancy BIO Intelligence Services described the current wide employment of life-cycle assessment in other industrial sectors.

Environmental friendliness often goes hand-in-hand with increased efficiency – offering industry competitive advantage.

Novel manufacturing processes such as ‘additive manufacturing’, where structures are built up in layers, or ‘friction stir welding’, where lower weld temperatures use less materials and energy to do a better job.

Example of additive manufacturing

Reducing the need for often costly waste disposal is another win–win: rocket maker Safran is working on a biological method of breaking down toxic solid-propellant waste.

Space: cleaner means safer

In Gravity, runaway orbital collisions fill low-Earth orbit with a lethal debris cloud.

In real life, of the 6000 satellites launched during the Space Age, less than 1000 remain operational. The rest are derelict and prone to fragment as leftover fuel or batteries explode.

Exploding satellite

Orbiting at 7.5 km/s or more, even a 2 cm screw has sufficient ‘lethal diameter’ to take out a satellite.

The workshop discussed various means of minimising future debris production, such as tethers or sails to help drag abandoned satellites out of low orbit within 25 years.

Satellite reentry also needs to be a safer process – sometimes entire chunks of satellites have hit the ground intact. New ‘design for demise’ concepts aim to prevent that.

But even if all space launches stop tomorrow, simulations show that debris levels will keep growing. Active removal is also needed, including robotic missions to repair or deorbit satellites.

For more information, visit ESA's new Clean Space website (see below link).

Related Links:

Clean Space Eco-design and Green Technologies Workshop 2012Gravity (film): http://www.esa.int/SPECIALS/DG/SEML5F1VW3H_0.html

Space agencies leading way to sustainable future: http://www.esa.int/SPECIALS/Technology/SEMN7QZW5VG_0.html

Clean Space website: http://www.esa.int/TEC/Clean_Space/

Images, Text, Credits: ESA / Arcam AB.

Greetings, Orbiter.ch

lundi 9 juillet 2012

We have liftoff! of the Proton M Breeze M rocket and the SES-5 satellite


















ILS / ROSCOSMOS - SES-5 poster.

July 9, 2012

 Preparations to launch Proton-M rocket

Today at 6:38pm GMT - SES-5 launch with an ILS Proton-M rocket from Baikonur cosmodrome in Kazakhstan.

video
liftoff of the Proton M Breeze M rocket and the SES-5 satellite

SES’ high-powered Ku-band beams will bring incremental capacity over Africa, and the Nordic and Baltic countries to support DTH services. Its comprehensive C-band beams cover Africa, the Middle East and Europe to enable services such as GSM backhaul, VSAT applications, maritime communications and video distribution. SES-5 will also carry the first hosted L-band payload for the European Geostationary Navigation Overlay Service (EGNOS). The EGNOS payload, which was developed by the European Space Agency (ESA) and the European Commission (EC), will help verify, improve, and report on the reliability and accuracy of navigation positioning signals in Europe.

SES-5 satellite

The Proton M launch vehicle, utilizing a 5-burn Breeze M mission design, lift off from Pad 24 at Baikonur Cosmodrome, Kazakhstan, with the SES-5 satellite on board. The first three stages of the Proton use a standard ascent profile to place the orbital unit (Breeze M upper stage and the SES-5 satellite) into a sub-orbital trajectory. From this point in the mission, the Breeze M perform planned mission maneuvers to advance the orbital unit first to a circular parking orbit, then to an intermediate orbit, followed by a transfer orbit, and finally to a geostationary transfer orbit. Separation of the SES-5 satellite is scheduled to occur approximately 9 hours, 12 minutes after liftoff.

For more information about the Mission SES-5, visit: http://www.ilslaunch.com/mission-control/mission-ses-5

Images, Video, Text, Credits: ILS / ROSCOSMOS / Loral / Orbiter.ch.

Greetings, Orbiter.ch

Cosmic Cocoon











NASA - Chandra X-ray Observatory patch.

July 9, 2012


Using observations from NASA's Chandra X-ray Observatory, researchers have obtained the first X-ray evidence of a supernova shock wave breaking through a cocoon of gas surrounding the star that exploded. This discovery may help astronomers understand why some supernovas are much more powerful than others.

On Nov. 3, 2010, a supernova was discovered in the galaxy UGC 5189A, located about 160 million light years away. Using data from the All Sky Automated Survey telescope in Hawaii taken earlier, astronomers determined this supernova exploded in early October 2010.

This composite image of UGC 5189A shows X-ray data from Chandra in purple and optical data from Hubble Space Telescope in red, green and blue. SN 2010jl is the very bright X-ray source near the top of the galaxy.

Chandra X-ray Observatory

A team of researchers used Chandra to observe this supernova in December 2010 and again in October 2011. The supernova was one of the most luminous that has ever been detected in X-rays.

In the first Chandra observation of SN 2010jl, the X-rays from the explosion's blast wave were strongly absorbed by a cocoon of dense gas around the supernova. This cocoon was formed by gas blown away from the massive star before it exploded.

In the second observation taken almost a year later, there is much less absorption of X-ray emission, indicating that the blast wave from the explosion has broken out of the surrounding cocoon. The Chandra data show that the gas emitting the X-rays has a very high temperature -- greater than 100 million degrees Kelvin – strong evidence that it has been heated by the supernova blast wave.

In a rare example of a cosmic coincidence, analysis of the X-rays from the supernova shows that there is a second unrelated source at almost the same location as the supernova. These two sources strongly overlap one another as seen on the sky. This second source is likely to be an ultraluminous X-ray source, possibly containing an unusually heavy stellar-mass black hole, or an intermediate mass black hole.

For more information about Chandra X-ray Observatory, visit: http://www.nasa.gov/mission_pages/chandra/main/index.html

Images, Text, Credit: X-ray: NASA / CXC / Royal Military College of Canada/P.Chandra et al); Optical: NASA / STScI.

Best regards, Orbiter.ch

The Mysterious Case of the Disappearing Dust









NASA - WISE Mission patch.

July 9, 2012


This artist's concept illustrates a dusty planet-forming disk, similar to the one that vanished around the star called TYC 8241 2652. Image credit: NASA / JPL-Caltech.

Imagine if the rings of Saturn suddenly disappeared. Astronomers have witnessed the equivalent around a young sun-like star called TYC 8241 2652. Enormous amounts of dust known to circle the star are unexpectedly nowhere to be found.

"It's like the classic magician's trick: now you see it, now you don't. Only in this case we're talking about enough dust to fill an inner solar system and it really is gone!" said Carl Melis of the University of California, San Diego, who led the new study appearing in the July 5 issue of the journal Nature.

A dusty disk around TYC 8241 2652 was first seen by the NASA Infrared Astronomical Satellite (IRAS) in 1983, and continued to glow brightly for 25 years. The dust was thought to be due to collisions between forming planets, a normal part of planet formation. Like Earth, warm dust absorbs the energy of visible starlight and reradiates that energy as infrared, or heat, radiation.

The first strong indication of the disk's disappearance came from images taken in January 2010 by NASA's Wide-field Infrared Survey Explorer, or WISE. An infrared image obtained at the Gemini telescope in Chile on May 1, 2012, confirmed that the dust has now been gone for two-and-a-half years.

"Nothing like this has ever been seen in the many hundreds of stars that astronomers have studied for dust rings," said co-author Ben Zuckerman of UCLA, whose research is funded by NASA. "This disappearance is remarkably fast even on a human time scale, much less an astronomical scale. The dust disappearance at TYC 8241 2652 was so bizarre and so quick, initially I figured that our observations must simply be wrong in some strange way."

Wide-field Infrared Survey Explorer (WISE). Image credit: NASA / JPL-Caltech

The astronomers have come up with a couple of possible solutions to the mystery, but they say none are compelling. One possibility is that gas produced in the impact that released the dust helped to quickly drag the dust particles into the star and thus to their doom. In another possibility, collisions of large rocks left over from an original major impact provide a fresh infusion of dust particles into the disk, which caused the dust grains to chip apart into smaller and smaller pieces.

The result is based upon multiple sets of observations of TYC 8241 2652 obtained with the Thermal-Region Camera Spectrograph on the Gemini South telescope in Chile; IRAS; WISE; NASA's Infrared Telescope on Mauna Kea in Hawaii; the European Space Agency's Herschel Space Telescope, in which NASA plays an important role; and the Japanese/European Space Agency AKARI infrared satellite.

Read the Gemini news release at http://www.gemini.edu/node/11836 , and the UCLA release at http://newsroom.ucla.edu/portal/ucla/astronomers-discover-a-houdini-235572.aspx .

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages, and operated, WISE for NASA's Science Mission Directorate. The spacecraft was put into hibernation mode after it scanned the entire sky twice, completing its main objectives. Edward Wright is the principal investigator and is at UCLA. The mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

IRAS was executed jointly by the United States (NASA), the Netherlands and the United Kingdom. The Infrared Telescope is operated and managed for NASA by the University of Hawaii, located in Honolulu.

More information is online at http://www.nasa.gov/wise, http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise

Images (mentioned), Text, Credit: NASA / JPL / Whitney Clavin.

Greetings, Orbiter.ch