'Earth-like' snow falls on Mars: study

A colour-enhanced image from the Phoenix lander shows the Martian surface at night, covered with a thin film of frost or snow. (Courtesy of Science)

On Mars, snow falls in the early morning from wispy, feathery clouds that many Earthlings would recognize as cirrus clouds, a Canadian-led research team has reported.

"We found ice clouds and precipitation that were surprisingly Earth-like – certainly more so than expected," said Jim Whiteway, the professor at Toronto's York University who headed the study published Friday in Science. It was the first time precipitation had been observed falling to the ground on Mars.

Whiteway told CBC News that the Martian clouds are similar to very thin clouds seen in Earth's Arctic in the winter.

"They're called diamond dust. And if you look up at the sky, you can still see the stars, but you see some sparkling ice crystals falling, sparkling in the moonlight."

Whiteway and 22 collaborators used data gathered by NASA's Phoenix Mars Lander using a Canadian-designed light-detection-and-ranging (LIDAR) instrument. The lander spent five months in the Martian Arctic during the Martian summer last year and completed its mission in November.

Prior to the mission, Whiteway said, researchers knew that the polar ice caps advanced as far south as the Phoenix site, located at 62 degrees north, in winter.

"But we didn't know how the water vapour moved from the atmosphere to ice on the ground," Whiteway said.

NASA first reported Phoenix's observations of falling snow in September, but at that time it wasn't clear whether the snow ever made it to the ground. Now that the data has been analyzed, researchers think they have a better understanding of the water cycle on Mars.

During the day, they suggest, the water vapour is lifted by turbulence and convection. At night, as the temperature drops below the frost point, it forms ice crystal clouds and falls back to the surface as snow.

The LIDAR was part of the Phoenix's meteorological station. The instrument fires a laser into the sky, then measures the backscattered light, similar to the way radar emits and detects radio waves or microwaves. Signals detected on Mars can be compared to LIDAR signals of clouds and precipitation on Earth.

Clouds creep out at midnight

The Mars data showed that during the day, there were no clouds in the atmosphere, just dust. However, starting at midnight, clouds were detected near the surface, and at 1 a.m., a second cloud layer started forming about four kilometres above the surface.

(Time was measured in terms of local time at the site of the lander. A day on Mars is roughly equivalent in length to a day on Earth, lasting only 39 minutes longer.)

A few times, around 5 a.m., streaks indicating precipitation appeared in the signals. In one case, the snow fell to the lowest level detectable by the instrument — about 50 metres above the surface.

"It is reasonable to assume that the ice crystals would have continued to descend through the saturated air to reach the surface," the paper said.

'It would look like frost'

However, Whiteway thinks the snow cover on the ground would have been very thin.

"It would look like frost," he said.

A photograph of the Martian surface taken by the lander shows what appears to be a film of frost on the rocks and dust, but Whiteway said there is no way to tell from one image whether some of that was snow, particularly since there also would have been frost anyway.

Twenty-three authors contributed to the study, including researchers at Dalhousie University, the Geological Survey of Canada, the Canadian Space Agency, Vaughan, Ont.-based Optech Inc. and Brampton, Ont.-based MacDonald Dettwiler and Associates, as well as a number of U.S. and Belgian researchers. The Phoenix mission received $37 million US in funding from the Canadian Space Agency.

The mission also discovered a layer of ice water five to 18 centimetres beneath the soil at the Martian north pole, and there is evidence that water has physically modified the soil there in the past. Those findings, also published in Science Friday, suggest the area might once have been habitable by life as we know it.

Read the whole article on CBC: Technology & Science

A Fireworks Display in the Helix Nebula

showing cometary shaped knots. Knots have gradually formed from material ejected from stars in the past, which are now exposed to ultraviolet radiation and wind from the central star.

The Helix Nebula, NGC 7293, is not only one of the most interesting and beautiful planetary nebulae; it is also one of the closest nebulae to Earth, at a distance of only 710 light years away. This new image, taken with an infrared camera on the Subaru Telescope in Hawaii, shows tens of thousands of previously unseen comet-shaped knots inside the nebula. The sheer number of knots--more than have ever been seen before—looks like a massive fireworks display in space.

The Helix Nebula was the first planetary nebula in which knots were seen, and their presence may provide clues to what planetary material may survive at the end of a star’s life. Planetary nebulae are the final stages in the lives of low-mass stars, such as our Sun. As they reach the ends of their lives they throw off large amounts of material into space. Although the nebula looks like a fireworks display, the process of developing a nebula is neither explosive nor instantaneous; it takes place slowly, over a period of about 10,000 to 1,000,000 years. This gradual process creates these nebulae by exposing their inner cores, where nuclear burning once took place and from which bright ultraviolet radiation illuminates the ejected material.

Astronomers from the National Astronomical Observatory of Japan (NAOJ), from London, Manchester and Kent universities in the UK and from a university in Missouri in the USA studied the emissions from hydrogen molecules in the infrared and found that knots are found throughout the entire nebula. Although these molecules are often destroyed by ultraviolet radiation in space, they have survived in these knots, shielded by dust and gas that can be seen in optical images. The comet-like shape of these knots results from the steady evaporation of gas from the knots, produced by the strong winds and ultraviolet radiation from the dying star in the center of the nebula.

Unlike previous optical images of the Helix Nebula knots, the infrared image shows thousands of clearly resolved knots, extending out from the central star at greater distances than previously observed. The extent of the cometary tails varies with the distance from the central star, just as Solar System comets have larger tails when they are closer to the Sun and when wind and radiation are stronger. “This research shows how the central star slowly destroys the knots and highlights the places where molecular and atomic material can be found in space,”says lead astronomer Dr. Mikako Matsuura, previously at NAOJ and now from University College London.

These images enable astronomers to estimate that there may be as many as 40,000 knots in the entire nebula, each of which are billions of kilometers/miles across. Their total mass may be as much as 30,000 Earths, or one-tenth the mass of our Sun. The origin of the knots is currently unknown. Are they remnants of the star's planetary system or are they material ejected from the star at some stage in its life? Either answer will help astronomers answer important questions about the lives of stars and planetary systems.

The innovative technology of the Subaru Telescope with its near-infrared camera, MOIRCS, enabled researchers to produce such impressive images. Mounted on one of the largest infrared optical telescopes in the world, MOIRCS (Multi-object Infrared Camera and Spectrograph) has a large (4 arcmin by 7 arcmin) field of view, allowing it to capture, with a single shot, such detailed features in a large PN.

This paper will be published in the Astrophysical Journal in August 2009

To view the impressive images to which this article refers, visit The Subaru Telescope's website: www.naoj.org

NASA's Fermi Telescope reveals a population of radio-quiet gamma-ray pulsars

A new class of pulsars detected by NASA's Fermi Gamma-ray Space Telescope is solving the mystery of previously unidentified gamma-ray sources and helping scientists understand the mechanisms behind pulsar emissions. A study to be published by an international team of scientists in the July 2 edition of Science Express describes 16 pulsars discovered by Fermi based on their pulsed emissions of high-energy gamma rays. A pulsar is a rapidly spinning neutron star, the dense core left behind after a supernova explosion. Most of the 1,800 known pulsars were found through their periodic radio emissions.

"These are the first pulsars ever detected by gamma rays alone, and already we've found 16," said coauthor Robert Johnson, professor of physics at the University of California, Santa Cruz. "The existence of a large population of radio-quiet pulsars was suspected prior to this, but until Fermi was launched, only one radio-quiet pulsar was known, and it was first detected in x-rays."

Johnson and other physicists at UCSC's Santa Cruz Institute for Particle Physics (SCIPP) identified the gamma-ray pulsars using computational techniques they developed to comb through data from Fermi's Large Area Telescope (LAT). Marcus Ziegler, a postdoctoral researcher at SCIPP and corresponding author of the paper, said detection of gamma-ray pulsations from a typical source requires weeks or months of data from the LAT.

"From the faintest pulsar we studied, the LAT sees only two gamma-ray photons a day," Ziegler said.

Of the 16 gamma-ray pulsars found by Fermi, 13 are associated with unidentified gamma-ray sources detected previously by the EGRET instrument on the Compton Gamma-ray Observatory. EGRET detected nearly 300 gamma-ray point sources, but was unable to detect pulsations from those sources, most of which have remained unidentified, said Pablo Saz Parkinson, also a SCIPP postdoctoral researcher and corresponding author of the paper.

"It's been a longstanding question what could be powering those unidentified sources, and the new Fermi results tell us that a lot of them are pulsars," Saz Parkinson said. "These findings are also giving us important clues about the mechanism of pulsar emissions."

A pulsar emits narrow beams of radio waves from the magnetic poles of the neutron star, and the beams sweep around like a lighthouse beacon because the magnetic poles are not aligned with the star's spin axis. If the radio beam misses the Earth, the pulsar cannot be detected by radio telescopes. Fermi's ability to detect so many radio-quiet gamma-ray pulsars indicates that the gamma-rays are emitted in a beam that is wider and more fan-like than the radio beam.

"This favors models in which the gamma rays are emitted from the outer magnetosphere of the pulsar, as opposed to the polar cap much closer to the surface of the star," Saz Parkinson said.

The very intense magnetic and electric fields of a pulsar accelerate charged particles to nearly the speed of light, and these particles are ultimately responsible for the gamma-ray emissions.

Because the rotation of the star powers the emissions, isolated pulsars slow down as they age and lose energy. But a binary companion star can feed material to a pulsar and spin it up to a rotation rate of 100 to 1,000 times a second. These are called millisecond pulsars, and Fermi scientists detected gamma-ray pulsations from eight millisecond pulsars that were previously discovered at radio wavelengths. Those results are reported in a second study also published in the July 2 edition of Science Express.

"Fermi has truly unprecedented power for discovering and studying gamma-ray pulsars," said Paul Ray of the Naval Research Laboratory in Washington. "Since the demise of the Compton Gamma Ray Observatory a decade ago, we've wondered about the nature of unidentified gamma-ray sources it detected in our galaxy. These studies from Fermi lift the veil on many of them."

Source: University of California - Santa Cruz

VLBA locates superenergetic bursts near giant black hole

Using a worldwide combination of diverse telescopes, astronomers have discovered that a giant galaxy's bursts of very high energy gamma rays are coming from a region very close to the supermassive black hole at its core. The discovery provides important new information about the mysterious workings of the powerful "engines" in the centers of innumerable galaxies throughout the Universe. The galaxy M87, 50 million light-years from Earth, harbors at its center a black hole more than six billion times more massive than the Sun. Black holes are concentrations of matter so dense that not even light can escape their gravitational pull. The black hole is believed to draw material from its surroundings -- material that, as it falls toward the black hole, forms a tightly-rotating disk.

Processes near this "accretion disk," powered by the immense gravitational energy of the black hole, propel energetic material outward for thousands of light-years. This produces the "jets" seen emerging from many galaxies. In 1998, astronomers found that M87 also was emitting flares of gamma rays a trillion times more energetic than visible light.

However, the telescopes that discovered these bursts of very high energy gamma rays could not determine exactly where in the galaxy they originated. In 2007 and 2008, the astronomers using these gamma-ray telescopes combined forces with a team using the National Science Foundation's continent-wide Very Long Baseline Array (VLBA), a radio telescope with extremely high resolving power, or ability to see fine detail.

"Combining the gamma-ray observations with the supersharp radio 'vision' of the VLBA allowed us to see that the gamma rays are coming from a region very near the black hole itself," said Craig Walker, of the National Radio Astronomy Observatory (NRAO).

"Pinning down this location addresses what was an open question and provides important clues for understanding how such highly energetic emissions are produced in the jets of active galaxies," said Matthias Beilicke, of Washington University in St. Louis, MO.

The gamma-ray flares from the galaxy were monitored by systems of large telescopes designed to detect faint flashes of blue light that result when gamma rays enter the Earth's atmosphere. Data from sensitive cameras in these systems can allow astronomers to infer the energy of the gamma rays and the direction from which they came. Their directional information, however, is not precise enough to narrow down the gamma-ray-emitting region within the galaxy.

The VLBA offered a millionfold improvement in resolving power, allowing the scientists to determine that the gamma rays are coming from the immediate vicinity of the black hole. Though gamma rays are the most energetic form of electromagnetic radiation and radio waves the least energetic, both often arise from the same regions. This was shown clearly when M87's most energetic gamma-ray flares were accompanied by the largest flare of radio waves seen from that galaxy by the VLBA.

The radio flare began at about the time of the gamma-ray flares, but continued to increase in brightness for at least two months. "This tells us that energetic material burst out very close to the black hole, causing the gamma rays to be emitted and the radio flare to begin. As that material traveled down the jet, expanding and losing energy, the gamma-ray emission ceased, but the radio continued to increase in brightness," Walker explained. "The VLBA showed us with great precision where the radio emission came from, so we know the gamma rays came from closer in toward the black hole," he added.

M87 is the largest galaxy in the Virgo Cluster of galaxies, at the center of a supercluster of galaxies that includes the Local Group, of which our own Milky Way is a member. The black hole in M87 has an "event horizon," from which matter cannot escape, roughly twice the size of our Solar System, or a tiny fraction of the size of the entire galaxy. The new measurements indicate that the gamma rays are coming from an area no larger than 50 times the size of the event horizon.

The telescope systems that detected the gamma-ray flares are the VERITAS array in Arizona, the H.E.S.S. system in Namibia, Africa, and the MAGIC system on La Palma in the Canary Islands.

Source: National Radio Astronomy Observatory

First Moon Images From NASA's Lunar Reconnaissance Orbiter

NASA's Lunar Reconnaissance Orbiter has transmitted its first images since reaching the moon on June 23. The spacecraft's two cameras, collectively known as the Lunar Reconnaissance Orbiter Camera, or LROC, were activated June 30. The cameras are working well and have returned images of a region in the lunar highlands south of Mare Nubium (Sea of Clouds).

As the moon rotates beneath LRO, LROC gradually will build up photographic maps of the lunar surface.

"Our first images were taken along the moon's terminator -- the dividing line between day and night -- making us initially unsure of how they would turn out," said LROC Principal Investigator Mark Robinson of Arizona State University in Tempe. "Because of the deep shadowing, subtle topography is exaggerated, suggesting a craggy and inhospitable surface. In reality, the area is similar to the region where the Apollo 16 astronauts safely explored in 1972. While these are magnificent in their own right, the main message is that LROC is nearly ready to begin its mission."

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These images show cratered regions near the moon's Mare Nubium region, as photographed by the Lunar Reconnaissance Orbiter's LROC instrument. Each image shows a region 1,400 meters (0.87 miles) wide. the bottoms of both images face lunar north. The image below shows the location of these two images in relation to each other. Credit: NASA/Goddard Space Flight Center/Arizona State University

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Neil deGrasse Tyson Interview on The Colbert Report

Neil deGrasse Tyson Interview on The Colbert Report (6-29-2009)
The ever-personable Neil deGrasse Tyson returns to the Report to give Stephen a lesson in astrophysics.

XMM-Newton discovers a new class of black holes

Illustration of HLX-1 (blue star to the upper left hand side of the galactic bulge). HLX-1, located on the outskirts of the spiral galaxy ESO 243-49, is the strongest candidate to- date of intermediate-mass black holes. Credits: Heidi Sagerud

Astronomers using ESA’s XMM-Newton X-ray observatory have discovered a black hole weighing more than 500 solar masses, a missing link between lighter stellar-mass and heavier supermassive black holes, in a distant galaxy. This discovery is the best detection to date of a new class that has long been searched for: intermediate mass black holes.

Due to appear tomorrow in the journal Nature, the discovery has been made by an international team of researchers working with XMM-Newton data, led by Sean Farrell from the Centre d’Etude Spatiale des Rayonnements, now based at the University of Leicester.

Stellar-mass black holes (about three to twenty times as massive as the Sun) and supermassive black holes (several million to several thousand million times as massive as the Sun) have long been known to exist. Because of the large gap between these two extremes, scientists have speculated the existence of a third, intermediate class of black holes, with masses between a hundred and several hundred thousand solar masses.

Up until now, scientists were unable to confirm that this elusive intermediate class actually existed.


Farrell’s team were analysing archived data obtained by XMM-Newton, looking for neutron stars and white dwarves, when they stumbled upon a most peculiar object that was observed on 23 November 2004.

Called HLX-1 (Hyper-Luminous X-ray source 1), it lies towards the outskirts of the galaxy ESO 243-49, approximately 290 million light-years from Earth. If it is indeed located in this distant galaxy, HLX-1 is very luminous in X-rays; peaking at 260 million times the luminosity of the Sun.

On analysing the light originating from HLX-1, the team found that the X-ray signature was inconsistent with any object other than a feeding black hole. The measured brightness was too low for it to be in our own Galaxy, and the lack of observed radio or optical emission from the location of HLX-1 in addition to the observed X-ray signature indicates that it is unlikely to be a background galaxy.

This means that the source of the X-ray emission must lie in ESO 243-49. Its location is too far away from the galactic centre for it to be a supermassive black hole, and too bright for a stellar-mass black hole feeding at the maximum rate.

To be sure that this really was a single astronomical object, and not a cluster of several fainter sources that was shining brightly, the team used XMM-Newton to observe it again on 28 November 2008.

Comparing the two observations, they found that the signature of X-rays originating from HLX-1 varied significantly in time and concluded from this that it must be a single object. They found that the only way to explain its intense luminosity was if HLX-1 harboured a black hole greater than 500 solar masses. No other physical explanation could account for what they had seen.


The few intermediate-mass black hole candidates that have been discovered so far could be accounted for by other theories, but this one stood out as it was brighter than all the previous candidates by a factor of almost 10. The team had their hands on the best detection of an intermediate mass black holes to-date.

While it is already known that stellar-mass black holes are the remnants of massive stars, how supermassive black holes form is still unknown. One of the possible scenarios involves mergers of intermediate mass black holes. To ratify such a theory, it is essential to prove their existence in the first place.


This is why detections such as this by XMM-Newton are essential. It will help to understand just how supermassive black holes, such as that at the centre of our Galaxy, form.

The team have planned further observations in X-ray, ultraviolet, optical, infrared and radio wavelengths in the near future to better understand this unique object and the environment around it.

University of Hawaii at Manoa astronomers discover pair of solar systems in the making

Left: This is a Submillimeter Array image of 253-1536 taken at a wavelength of 880 microns. The mass of the disk on the left is 70 times the mass of Jupiter, while the one on the right is 20 Jupiter masses. Right: The optical image taken by the Hubble Space Telescope shows the shadow of the large disk, but the smaller disk is obscured in the glare of the brighter star.

Two University of Hawai'i at Mānoa astronomers have found a binary star-disk system in which each star is surrounded by the kind of dust disk that is frequently the precursor of a planetary system. Doctoral student Rita Mann and Dr. Jonathan Williams used the Submillimeter Array on Mauna Kea, Hawaii to make the observations. A binary star system consists of two stars bound together by gravity that orbit a common center of gravity. Most stars form as binaries, and if both stars are hospitable to planet formation, it increases the likelihood that scientists will discover Earth-like planets.

This binary system, 253-1536, stands out as the first known example of two optically visible stars, each surrounded by a disk with enough mass to form a planetary system like our own. It lies 1,300 light-years from Earth, in the famous Orion Nebula, the kind of rich cluster of stars that is a common birth environment for most stars in our Milky Way galaxy, including our sun.

One of the disks was discovered in an image taken with the Hubble Space Telescope, but the other disk was hidden in the glare of the star. Hubble saw only the disk shadow, so the amount of material and its capability for planet formation was unknown until the UH team made the SMA observations. "The SMA was able to image the binary system at almost the same level of detail as the Hubble Space Telescope, but in the extreme infrared, where we can see the glow from the dust, rather than its shadow," explained Mann.

The two stars are 400 times farther from each other than Earth is from the sun. They would take 4,500 years, or about the length of human recorded history, to complete one orbit around their common center. Both stars are only about a third the mass of our sun and are much cooler and redder in color. Viewed from a potential future planet, the stellar neighbor would appear as an intense point in the night sky, about one thousand times brighter than the brightest star in our night sky, Sirius. Planets around the other star would be visible only through telescopes, but they would be within reach of spacecraft from a civilization with the same level of technology as ours.

The larger disk in 253-1536 is also the most massive found in the Orion Nebula so far. The discovery of this massive disk and the binary disk system improve our understanding of how common planet formation is in our Galaxy and place our Solar System in context.

Source: University of Hawaii at Manoa

Intense heat killed the Universe's would-be galaxies, researchers say

Our Milky Way galaxy only survived because it was already immersed in a large clump of dark matter which trapped gases inside it, scientists led by Durham University's Institute for Computational Cosmology (ICC) found. The research, to be presented at an international conference today (Wednesday, July 1), also forms a core part of a new ICC movie charting the evolution of the Milky Way to be shown at the Royal Society.

The researchers said that the early Milky Way, which had begun forming stars, held on to the raw gaseous material from which further stars would be made. This material would otherwise have been evaporated by the high temperatures generated by the "ignition" of the Universe about half-a-billion years after the Big Bang.

Tiny galaxies, inside small clumps of dark matter, were blasted away by the heat which reached approximate temperatures of between 20,000 and 100,000 degrees centigrade, the scientists, including experts at Japan's University of Tsukuba, said.

Dark matter is thought to make up 85 per cent of the Universe's mass and is believed to be one of the building blocks of galaxy formation.

Using computer simulations carried out by the international Virgo Consortium (which is led by Durham) the scientists examined why galaxies like the Milky Way have so few companion galaxies or satellites.

Astronomers have found a few dozen small satellites around the Milky Way, but the simulations revealed that hundreds of thousands of small clumps of dark matter should be orbiting our galaxy.

The scientists said the heat from the early stars and black holes rendered this dark matter barren and unable to support the development of satellite star systems.

The findings will be presented to The Unity of the Universe conference to be held at the Institute of Cosmology and Gravitation, at the University of Portsmouth on Wednesday, July 1. The work has been funded by the Science and Technology Facilities Council (STFC) and the Japanese Society for the Promotion of Science.

The simulations also form part of a new ICC movie – called Our Cosmic Origins – which combines ground-breaking simulations with observations of galaxies to track the evolution of the Milky Way over the 13-billion-year history of the Universe.

The movie is part of the ICC's exhibit at The Royal Society's annual Summer Science Exhibition which runs until this Saturday (July 4).

Joint lead investigator Professor Carlos Frenk, Director of the Institute for Computational Cosmology, at Durham University, said: "The validity of the standard model of our Universe hinges on finding a satisfactory explanation for why galaxies like the Milky Way have so few companions.

"The simulations show that hundreds of thousands of small dark matter clumps should be orbiting the Milky Way, but they didn't form galaxies.

"We can demonstrate that it was almost impossible for these potential galaxies to survive the extreme heat generated by the first stars and black holes.

"The heat evaporated gas from the small dark matter clumps, rendering them barren. Only a few dozen front-runners which had a head start on making stars before the Universe ignited managed to survive."

By providing a natural explanation for the origin of galaxies, the simulations support the view that cold dark matter is the best candidate for the mysterious material believed to make up the majority of our Universe, the scientists added.

It is now up to experimental physicists to either find this dark matter directly or to make it in a particle accelerator such as the Large Hadron Collider at CERN.

Professor Frenk, added: "Identifying the dark matter is not only one of the most pressing problems in science today, but also the key to understanding the formation of galaxies."

Joint lead investigator Dr Takashi Okamoto from the University of Tsukuba said: "These are still early days in trying to make realistic galaxies in a computer, but our results are very encouraging."

Source: Durham University

Largest ever survey of very distant galaxy clusters completed

An international team of researchers led by a UC Riverside astronomer has completed the largest ever survey designed to find very distant clusters of galaxies. Named the Spitzer Adaptation of the Red-sequence Cluster Survey, "SpARCS" detects galaxy clusters using deep ground-based optical observations from the CTIO 4m and CFHT 3.6m telescopes, combined with Spitzer Space Telescope infrared observations.

In a universe which astronomers believe to be 13.7 billion years old, SpARCS is designed to find clusters, snapped as they appeared long ago in time, when the universe was 6 billion years old or younger.

Clusters of galaxies are rare regions of the universe consisting of hundreds of galaxies containing trillions of stars, plus hot gas and mysterious dark matter. Most of the mass in clusters is actually in the form of invisible dark matter which astronomers are convinced exists because of its influence on the orbits of the visible galaxies.

An example of one of the most massive clusters found in the SpARCS survey is shown in the accompanying image. Seen when the universe was a mere 4.8 billion years old, this is also one of the most distant clusters ever discovered. Many similar-color red cluster galaxies can be seen in the image (the green blobs are stars in our own galaxy, The Milky Way).

"We are looking at massive structures very early in the universe's history," said Gillian Wilson, an associate professor of physics and astronomy who leads the SpARCS project.

The SpARCS survey has discovered about 200 new cluster candidates.

"It is very exciting to have discovered such a large sample of these rare objects," Wilson said. "Although we are catching these clusters at early times, we can tell by their red colors that many of the galaxies we are seeing are already quite old. We will be following up this new sample for years to come, to better understand how clusters and their galaxies form and evolve in the early universe."

Source: University of California - Riverside

Astronomer's new guide to the galaxy: largest map of cold dust revealed

Colour-composite annotated image of part of the Galactic Plane seen by the ATLASGAL survey, divided into sections. In this image, the ATLASGAL submillimetre-wavelength data are shown in red, overlaid on a view of the region in infrared light, from the Midcourse Space Experiment (MSX) in green and blue. The total size of the image is approximately 42 degrees by 1.75 degrees.

Some of the most prominent features visible in the image are (from left to right, top to bottom):

• Messier 20 (the Trifid Nebula): A nebula containing an open cluster of stars as well as a stellar nursery. The name “Trifid” refers to the way that dense dust appears to divide it into three lobes at visible wavelengths.
• Sagittarius B2 (Sgr B2): One of the largest clouds of molecular gas in the Milky Way, this dense region lies close to the Galactic Centre and is rich in many different interstellar molecules.
• Galactic Centre: The centre of the Milky Way, home to a supermassive black hole more than four million times the mass of our Sun. It is about 25 000 light-years from Earth.
• NGC 6357: A diffuse nebula containing the open cluster Pismis 24, home to several very massive stars.
• NGC 6334: An emission nebula also known as the “Cat’s Paw Nebula”.
• RCW 120: A region where an expanding bubble of ionised gas about ten light-years across is causing the surrounding material to collapse into dense clumps that are the birthplaces of new stars.
• The Norma Arm: The region of somewhat brighter emission extending over about 10 degrees on the right-hand side of the image corresponds to the position of the Norma Arm, one of the spiral arms of the Milky Way.

This image in full-resolution (TIF format, 46 MB) is available on this link.

Astronomers have unveiled an unprecedented new atlas of the inner regions of the Milky Way, our home galaxy, peppered with thousands of previously undiscovered dense knots of cold cosmic dust — the potential birthplaces of new stars. Made using observations from the APEX telescope in Chile, this survey is the largest map of cold dust so far, and will prove an invaluable map for observations made with the forthcoming ALMA telescope, as well as the recently launched ESA Herschel space telescope.

This new guide for astronomers, known as the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) shows the Milky Way in submillimetre-wavelength light (between infrared light and radio waves [1]). Images of the cosmos at these wavelengths are vital for studying the birthplaces of new stars and the structure of the crowded galactic core.

“ATLASGAL gives us a new look at the Milky Way. Not only will it help us investigate how massive stars form, but it will also give us an overview of the larger-scale structure of our galaxy”, said Frederic Schuller from the Max Planck Institute for Radio Astronomy, leader of the ATLASGAL team.

The area of the new submillimetre map is approximately 95 square degrees, covering a very long and narrow strip along the galactic plane two degrees wide (four times the width of the full Moon) and over 40 degrees long. The 16 000 pixel-long map was made with the LABOCA submillimetre-wave camera on the ESO-operated APEX telescope. APEX is located at an altitude of 5100 m on the arid plateau of Chajnantor in the Chilean Andes — a site that allows optimal viewing in the submillimetre range. The Universe is relatively unexplored at submillimetre wavelengths, as extremely dry atmospheric conditions and advanced detector technology are required for such observations.

The interstellar medium — the material between the stars — is composed of gas and grains of cosmic dust, rather like fine sand or soot. However, the gas is mostly hydrogen and relatively difficult to detect, so astronomers often search for these dense regions by looking for the faint heat glow of the cosmic dust grains.

Submillimetre light allows astronomers to see these dust clouds shining, even though they obscure our view of the Universe at visible light wavelengths. Accordingly, the ATLASGAL map includes the denser central regions of our galaxy, in the direction of the constellation of Sagittarius — home to a supermassive black hole (ESO 46/08) — that are otherwise hidden behind a dark shroud of dust clouds.

The newly released map also reveals thousands of dense dust clumps, many never seen before, which mark the future birthplaces of massive stars. The clumps are typically a couple of light-years in size, and have masses of between ten and a few thousand times the mass of our Sun. In addition, ATLASGAL has captured images of beautiful filamentary structures and bubbles in the interstellar medium, blown by supernovae and the winds of bright stars.

Some striking highlights of the map include the centre of the Milky Way, the nearby massive and dense cloud of molecular gas called Sagittarius B2, and a bubble of expanding gas called RCW120, where the interstellar medium around the bubble is collapsing and forming new stars (see ESO 40/08).

“It’s exciting to get our first look at ATLASGAL, and we will be increasing the size of the map over the next year to cover all of the galactic plane visible from the APEX site on Chajnantor, as well as combining it with infrared observations to be made by the ESA Herschel Space Observatory. We look forward to new discoveries made with these maps, which will also serve as a guide for future observations with ALMA”, said Leonardo Testi from ESO, who is a member of the ATLASGAL team and the European Project Scientist for the ALMA project.

Note

[1] The map was constructed from individual APEX observations in radiation at 870 µm (0.87 mm) wavelength.

More information:

The ATLASGAL observations are presented in a paper by Frederic Schuller et al., ATLASGAL — The APEX Telescope Large Area Survey of the Galaxy at 870 µm, published in Astronomy & Astrophysics. ATLASGAL is a collaboration between the Max Planck Institute for Radio Astronomy, the Max Planck Institute for Astronomy, ESO, and the University of Chile.

LABOCA (Large APEX Bolometer Camera), one of APEX’s major instruments, is the world’s largest bolometer camera (a "thermometer camera", or thermal camera that measures and maps the tiny changes in temperature that occur when sub-millimetre wavelength light falls on its absorbing surface; see ESO 35/07). LABOCA’s large field of view and high sensitivity make it an invaluable tool for imaging the “cold Universe”. LABOCA was built by the Max Planck Institute for Radio Astronomy.

The Atacama Pathfinder Experiment (APEX) telescope is a 12-metre telescope, located at 5100 m altitude on the arid plateau of Chajnantor in the Chilean Andes. APEX operates at millimetre and submillimetre wavelengths. This wavelength range is a relatively unexplored frontier in astronomy, requiring advanced detectors and an extremely high and dry observatory site, such as Chajnantor. APEX, the largest submillimetre-wave telescope operating in the southern hemisphere, is a collaboration between the Max Planck Institute for Radio Astronomy, the Onsala Space Observatory and ESO. Operation of APEX at Chajnantor is entrusted to ESO. APEX is a “pathfinder” for ALMA — it is based on a prototype antenna constructed for the ALMA project, it is located on the same plateau and will find many targets that ALMA will be able to study in extreme detail.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ESO is the European partner in ALMA. ALMA, the largest astronomical project in existence, is a revolutionary telescope, comprising an array of 66 giant 12-metre and 7-metre diameter antennas observing at millimetre and submillimetre wavelengths. ALMA will start scientific observations in 2011.

ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, 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. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links

• The ATLASGAL paper referred to is available online at : http://www.aanda.org/10.1051/0004-6361/200811568/pdf
• More about APEX: http://www.eso.org/apex
• APEX handout: http://www.eso.org/public/outreach/products/publ/handouts/pdf/apex-lr.pdf
• Max-Planck Press Release in German: http://www.mpifr-bonn.mpg.de/public/pr/pr-atlasgal-dt.html

Source: ESO

Landforms on Mars Add to Evidence for Recent Water

Domed polygons found throughout the Athabasca Vallis head-regions area. Credit: NASA/JPL/UofA

HiRISE (High Resolution Imaging Science Experiment) mosaic image of the Athabasca region examined in the new study. Credit: NASA/JPL/UofA

The weather on Mars was much balmier in the recent past than scientists have previously thought, according to a new interpretation of the formation of certain landforms on the surface.

The finding could have implications for the possibility of finding signs of life on Mars.

Matthew Balme, of The Open University in the United Kingdom, studied detailed images of equatorial landforms taken by the HiRISE (High Resolution Imaging Science Experiment) instrument onboard NASA's Mars Reconnaissance Orbiter (MRO), currently circling the red planet.

Ample evidence has been found to show that liquid water once covered parts of the Martian surface in the early history of the planet several billion years ago, but whether water flowed more recently has been less certain. Several studies in recent years have started to point to possible evidence of more recent water flow though.

For example, a system of gullies suggests the most recent period of water flow was only 1.25 million years ago. Another recent study found that rivers might have flowed on the Martian surface within the last billion years.

Balme's analysis indicates that the landforms he examined formed by the melting of ice-rich soils during "freeze-thaw" cycles that continued until as recently as 2 million years ago. The pictures show polygonally patterned surfaces, branched channels, blocky debris and mound/cone structures. These features are similar to landforms on Earth in areas where permafrost is melting.

Permafrost is ground that remains frozen for years or even millennia, such as in the Arctic, but which can melt if the climate changes.

"The features of this terrain [on Mars] were previously interpreted to be the result of volcanic processes. The amazingly detailed images from HiRISE show that the features are instead caused by the expansion and contraction of ice, and by thawing of ice-rich ground," Balme said. "This all suggests a very different climate to what we see today."

All of the landforms observed are in an outflow channel, thought to have been active as recently as 2 million to 8 million years ago. Since the landforms exist within, and cut across, the pre-existing features of the channel, this suggests that they too were created within this timeframe.

"These observations demonstrate not only that there was ice near the Martian equator in the last few million years, but also that the ice melted to form liquid water and then refroze. And this probably happened for many cycles," Balme said.

Balme's study, funded by a UK Science and Technology Facilities Council grant, will be detailed in an upcoming issue of the journal Earth and Planetary Science Letters.

Signs of more recent water activity could aide the search for past or present life on Mars as such life, or signs of it, would be more likely to have survived than any that might have existed earlier in the planet's history.

"Given that liquid water seems to be essential for life, these kinds of environments could be a great place to look for evidence of past life on Mars," Balme said.

Read the whole article on Space.com

NASA Selects New Astronauts for Future Space Exploration

After reviewing more than 3500 applications, NASA has selected nine men and women for the 2009 astronaut candidate class. They will begin training at NASA's Johnson Space Center, Houston, in August.

"This is a very talented and diverse group we've selected," said Bill Gerstenmaier, NASA associate administrator for Space Operations. "They will join our current astronauts and play very important roles for NASA in the future. In addition to flying in space, astronauts participate in every aspect of human spaceflight, sharing their expertise with engineers and managers across the country. We look forward to working with them as we transcend from the shuttle to our future exploration of space, and continue the important engineering and scientific discoveries aboard the International Space Station."

The new astronaut candidates:

Serena M. Aunon, 33, of League City, Texas; University of Texas Medical Branch-Wyle flight surgeon for NASA's Space Shuttle, International Space Station and Constellation Programs; born in Indianapolis, Ind. Aunon holds degrees from The George Washington University, University of Texas Health Sciences Center in Houston, and UTMB.

Jeanette J. Epps, 38, of Fairfax, Va.; technical intelligence officer with the Central Intelligence Agency; born in Syracuse, N.Y. Epps holds degrees from LeMoyne College and the University of Maryland.

Jack D. Fischer, Major U.S. Air Force, 35, of Reston, Va.; test pilot; U.S. Air Force Strategic Policy intern (Joint Chiefs of Staff) at the Pentagon; born in Boulder, Colo. Fischer is a graduate of the U.S. Air Force Academy and Massachusetts Institute of Technology.

Michael S. Hopkins, Lt. Colonel U.S. Air Force, 40, of Alexandria, Va.; special assistant to the Vice Chairman (Joint Chiefs of Staff) at the Pentagon; born in Lebanon, Mo. Hopkins holds degrees from the University of Illinois and Stanford University.

Kjell N. Lindgren, 36, of League City, Texas; University of Texas Medical Branch-Wyle flight surgeon for NASA's Space Shuttle, International Space Station and Constellation Programs; born in Taipei, Taiwan. Lindgren has degrees from the U.S. Air Force Academy, Colorado State University, University of Colorado, the University of Minnesota, and UTMB.

Kathleen (Kate) Rubins, 30, of Cambridge, Mass.; born in Farmington, Conn.; principal investigator and fellow, Whitehead Institute for Biomedical Research at MIT and conducts research trips to the Congo. Rubins has degrees from the University of California-San Diego and Stanford University.

Scott D. Tingle, Commander U.S. Navy, 43, of Hollywood, Md.; born in Attleboro, Mass.; test pilot and Assistant Program Manager-Systems Engineering at Naval Air Station Patuxent River. Tingle holds degrees from Southeastern Massachusetts University (now University of Massachusetts Dartmouth) and Purdue University.

Mark T. Vande Hei, Lt. Colonel U.S. Army, 42, of El Lago, Texas; born in Falls Church, Va.; flight controller for the International Space Station at NASA's Johnson Space Center, as part of U.S. Army NASA Detachment. Vande Hei is a graduate of Saint John's University and Stanford University.

Gregory R. (Reid) Wiseman, Lt. Commander U.S. Navy, 33, of Virginia Beach, Va.; born in Baltimore; test pilot; Department Head, Strike Fighter Squadron 103, USS Dwight D. Eisenhower, based out of Oceana Virginia. Wiseman is a graduate of Rensselaer Polytechnic Institute and Johns Hopkins University.

NASA Television's Video File will include b-roll of astronaut training beginning at xx a.m. EDT. For NASA TV streaming video, schedules and downlink information, visit:

http://www.nasa.gov/ntv

For more information about the International Space Station, visit:

http://ww.nasa.gov/station

For more information about astronaut selection and training, visit:

http://nasajobs.nasa.gov/astronauts/

Few Good Constellation Informative Videos

"Guests Bret Drake, Clarence Sams and Wendell Mendell explain future missions, the requirements of future explorers and the scientific and economic implications."

Astronaut Scott Parazynski chat with kids

Astronaut Scott Parazynski has a chat with Kids, any one of those could be next Niel Armstrong.

NASA and NOAA's GOES-O satellite successfully launched

The latest Geostationary Operational Environmental Satellite, GOES-O, soared into space today after a successful launch from Space Launch Complex 37 at the Cape Canaveral Air Force Station in Florida.

The GOES-O spacecraft lifted off at 22:51 UTC on a Delta IV rocket. The National Oceanic and Atmospheric Administration's GOES-O satellite will improve weather forecasting and monitor environmental events around the world. The satellite is the second to be launched in the GOES N series of geostationary environmental weather satellites.

"All indications are that GOES-O is in a normal orbit, with all spacecraft systems functioning properly," stated Andre Dress, GOES deputy project manager at NASA's Goddard Space Flight Center in Greenbelt, Md. "We are proud of our support teams and pleased with the performance of the Delta IV launch vehicle."

Approximately 4 hours and 21 minutes after launch, the spacecraft separated from the launch vehicle. The Universal Space Network Western Australia tracking site in Dongara monitored the spacecraft separation.

On July 7, GOES-O will be placed in its final orbit and renamed GOES-14. Approximately 24 days after launch, Boeing Space and Intelligence Systems will turn engineering control over to NASA. About five months later, NASA will transfer operational control of GOES-14 to NOAA. The satellite will be checked out, stored in orbit and available for activation should one of the operational GOES satellites degrade or exhaust its fuel.

Credit: NASA/Kim Shiflett

NASA contracted with Boeing to build and launch the GOES-O spacecraft. NASA's Launch Services Program at NASA's Kennedy Space Center in Florida supported the launch in an advisory role. NOAA manages the GOES program, establishes requirements, provides all funding and distributes environmental satellite data for the United States. Goddard procures and manages the design, development and launch of the satellites for NOAA on a cost-reimbursable basis.

Mars Odyssey THEMIS images - June 22-26, 2009

The following new images taken by the Thermal Emission Imaging System (THEMIS) on the Mars Odyssey spacecraft are now available:

• Unusual Textures (Released 22 June 2009)
  Odd rimmed depressions are located on the floor of this unnamed crater in Noachis Terra.
• Coprates Chasma (Released 23 June 2009)
  This VIS image crosses Coprates Chasma, showing both floor and wall features of the canyon.
• Sirenum Fossae (Released 24 June 2009)
  This VIS image shows a portion of the eastern end of Sirenum Fossae.
• Sirenum Fossae (Released 25 June 2009)
  This VIS image of the western portion of Sirenum Fossae shows mesa formation.
• Olympus Mons (Released 26 June 2009)
  This VIS image shows flow features on the northern flank of Olympus Mons.

Cassini ISS images - June 22-26, 2009

The following new images taken by the Imaging Science Subsystem (ISS) on the Cassini spacecraft are now available:

• Fascinating F Ring (Released 22 June 2009)
  In the lower center of this image, the Cassini spacecraft captures an intriguing feature of Saturn's tenuous F ring.
• Serene Enceladus (Released 23 June 2009)
  Saturn's moon Enceladus looks tranquil here, concealing the true nature of this active moon.
• Faint Spokes on a Ring (Released 24 June 2009)
  This high-phase image from the Cassini spacecraft shows dark areas separating faint spokes that are brighter than the rest of Saturn's B ring.
• Centered on Senkyo (Released 25 June 2009)
  The Cassini spacecraft examines the dark region of Senkyo on Saturn's largest moon, Titan.
• Exposing a Shadow (Released 26 June 2009)
  The shadow of the moon Tethys is revealed on Saturn's B and C rings in this image which also includes the planet.