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Saturday, July 31, 2010

First Dust Devil Seen by Opportunity


This is the first dust devil that NASA's Mars Exploration Rover Opportunity has observed in the rover's six and a half years on Mars. The whirlwind appeared in a routine drive-direction image taken by Opportunity's panoramic camera right after a drive during the 2,301st Martian day, or sol, of the rover's mission on Mars (July 15, 2010).

Contrast has been stretched and the image has been carefully calibrated to make the dust devil easier to see against the Martian sky.

Opportunity's twin, Spirit, has observed dozens of dust devils at its location in Gusev Crater halfway around Mars from Opportunity's location in the Meridiani Planum region. Opportunity conducted systematic searches for dust devils in past years without seeing any. A rougher and dustier surface at Gusev makes dust devils form more readily there than at Meridiani.

Photo credit: NASA/JPL-Caltech/Cornell University/Texas A&M

Friday, July 30, 2010

Nebula CTB 102


This image from NASA's Spitzer Space Telescope shows a wispy, vast structure in the constellation Perseus with a small bubble right in its center puffed out by the spasms of fresh-formed, heavyweight stars. A bubble far larger with age, down below it, has a tendril of gas sneaking across its mostly empty inner space. Along this dusty thread, stars are budding at the ends of matter columns, much like the famous "Pillars of Creation" seen by NASA's Hubble Space Telescope in the Eagle Nebula. To the middle right and out of the fray sparkles an older star cluster that has since thrown off its clouds of polycyclic aromatic hydrocarbons (PAHs), chemical compounds found in space and on Earth. Below this jewel-like collection, hydrogen atoms energized by starlight emit a rosy glow. This hue, common to many nebulae, also appears red to our eyes in visible light. The verdant PAHs signify neutral, less energized regions around this luminous hydrogen patch, and help researchers gauge the size and age of cosmic clouds.

This image is a combination of data from Spitzer and the Two Micron All Sky Survey (2MASS). The Spitzer data was taken after Spitzer's liquid coolant ran dry in May 2009, marking the beginning of its "warm" mission. Light from Spitzer's remaining infrared channels at 3.6 and 4.5 microns has been represented in green and red, respectively. 2MASS observations at 2.2 microns are blue.

Photo credit: NASA/JPL-Caltech/2MASS/SSI/University of Wisconsin

Note: This nebula is known as CTB 102; it is located 4.3 kiloparsecs (14,027 light-years) from the Sun, and is about 100-130 parsecs (326-424 light-years) in size.

Thursday, July 29, 2010

WR 22 and the Carina Nebula


A spectacular new image from ESO’s Wide Field Imager at the La Silla Observatory in Chile shows the brilliant and unusual star WR 22 and its colorful surroundings. WR 22 is a very hot and bright star that is shedding its atmosphere into space at a rate many millions of times faster than the Sun. It lies in the outer part of the dramatic Carina Nebula from which it formed.

Very massive stars live fast and die young. Some of these stellar beacons have such intense radiation passing through their thick atmospheres late in their lives that they shed material into space many millions of times more quickly than relatively sedate stars such as the Sun. These rare, very hot and massive objects are known as Wolf–Rayet stars, after the two French astronomers who first identified them in the mid-nineteenth century, and one of the most massive ones yet measured is known as WR 22. It appears at the center of this picture, which was created from images taken through red, green and blue filters with the Wide Field Imager on the MPG/ESO 2.2-meter telescope at ESO’s La Silla Observatory in Chile. WR 22 is a member of a double star system and has been measured to have a mass at least 70 times that of the Sun.

WR 22 lies in the southern constellation of Carina, the keel of Jason’s ship Argo in Greek mythology. Although the star lies over 5,000 light-years from the Earth it is so bright that it can just be faintly seen with the unaided eye under good conditions. WR 22 is one of many exceptionally brilliant stars associated with the beautiful Carina Nebula (also known as NGC 3372) and the outer part of this huge region of star formation in the southern Milky Way forms the colorful backdrop to this image.

The subtle colors of the rich background tapestry are a result of the interactions between the intense ultraviolet radiation coming from hot massive stars, including WR 22, and the vast gas clouds, mostly hydrogen, from which they formed. The central part of this enormous complex of gas and dust lies off the left side of this picture as can be seen in image eso1031b. This area includes the remarkable star Eta Carinae and was featured in an earlier press release (eso0905).

Photo credit: European Southern Observatory

Wednesday, July 28, 2010

The Journey of Ions in Space During Geomagnetic Storms


This computer animation illustrates the Earth's space storm shield in action. The solar wind, a thin, high-velocity electrified gas, or plasma, blows constantly from the Sun at an average speed of 400 km/s. It is represented as a stream of yellow particles flowing from the Sun. The solar wind impacts the Earth's magnetic field, represented by the blue lines. As the solar wind flows past the Earth's magnetic field, it generates enormous electric currents that heat Earth's space storm shield -- a layer in the Earth's electrically charged outer atmosphere (ionosphere) -- causing the shield to eject electrically charged oxygen atoms (oxygen ions) into space. The expelled oxygen ions are represented by the green particle streams. The ejected oxygen ions gain tremendous speed as they leave the atmosphere, become trapped by the Earth's magnetic field and ultimately encircle the Earth, where they form a billion-degree plasma cloud around the planet, represented by the red cloud. The blue doughnut shape represents the high-speed flow of these particles around the Earth. The red 'ring of fire' around the Earth's polar regions represents the contribution of the particles to the aurora (the northern and southern lights).

Animation Credit: NASA/Goddard Space Flight Center/Conceptual Image Lab

Note: For more information on this topic, see Earth's Space Storm Shield Offers Protection at a Price.

Tuesday, July 27, 2010

Vela A Molecular Cloud


New stars are forming inside this giant cloud of dust and gas as seen in infrared light by NASA's Wide-field Infrared Survey Explorer, or WISE. Sprawling across the constellation Vela is a complex of dark, dense clouds of dust and gas, difficult to detect with telescopes that see only visible light. The complex is called the Vela Molecular Cloud Ridge. This ridge may form part of the edge of the Orion spiral arm spur in our Milky Way galaxy. Astronomers mapping out the region in radio light in the late 1980s found four distinct regions of the densest gas and named them clouds A, B, C and D. This image takes in the first of those clouds, Vela A.

Vela A is about 3,300 light-years away. This image of Vela A covers a region on the sky over 4.5 full moons wide and over 3 full moons tall, spanning about 130 light-years in space. The core of the cloud is being excavated by the radiation and winds from hot, young stars. The energy from the new stars is absorbed by the surrounding dust. This hides them from view in visible light, but the heated dust glows in infrared light (seen here in green and red). Sprinkled around Vela A are a few groups of sources that appear very red in this image, and have no known counterparts in visible-light images of the region. It's possible that these may be Young Stellar Objects, which are stars in their very infancy enveloped in dust. The infrared light seen from these baby stars does not come directly from the stars, but rather from the dust around them, which glows as the nascent stars heat it.

All four infrared detectors aboard WISE were used to make this mosaic. Color is representational: blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust.

Photo credit: NASA/JPL-Caltech/UCLA

Monday, July 26, 2010

Schrödinger Impact Basin


Schrödinger Impact Basin (centered -75.0˚, 132.4˚ E), located on the lunar far side within South Pole-Aitken Basin, is not visible from the Earth. Crater counts suggest that the basin is less than one billion years old, making it the second youngest impact basin on the Moon (the youngest being Orientale). LOLA data reveal that the basin has approximately 3.3 km of relief from rim to floor. The basin’s inner ring is clearly visible, as are lunar rilles, smaller impact craters, and a volcanic cone (see arrow).

The cone is believed to be pyroclastic in nature, largely due to the dark halo that can be seen surrounding it in visible light images. The LRO narrow angle camera has also captured a view of the cone. Additional evidence for volcanic activity comes in the form of rilles and the relatively flat and smooth basin floor, which is most likely the result of infill by lava flows.

Schrödinger Basin is named for Erwin Schrödinger (1887-1961), a theoretical physicist who received the Nobel Prize in Physics in 1933 for the development of the Schrödinger equation and it contributions to quantum mechanics.

Photo credit: NASA

Sunday, July 25, 2010

Asteroid Lutetia


Asteroid Lutetia has been revealed as a battered world of many craters. ESA’s Rosetta mission has returned the first close-up images of the asteroid showing it is most probably a primitive survivor from the violent birth of the Solar System.

The flyby was a spectacular success with Rosetta performing faultlessly. Closest approach took place at 18:10 CEST [July 10], at a distance of 3,162 km.

The images show that Lutetia is heavily cratered, having suffered many impacts during its 4.5 billion years of existence. As Rosetta drew close, a giant bowl-shaped depression stretching across much of the asteroid rotated into view. The images confirm that Lutetia is an elongated body, with its longest side around 130 km.

The pictures come from Rosetta’s OSIRIS instrument, which combines a wide angle and a narrow angle camera. At closest approach, details down to a scale of 60 m can be seen over the entire surface of Lutetia.

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Rosetta operated a full suite of sensors at the encounter, including remote sensing and in-situ measurements. Some of the payload of its Philae lander were also switched on. Together they looked for evidence of a highly tenuous atmosphere, magnetic effects, and studied the surface composition as well as the asteroid’s density.

They also attempted to catch any dust grains that may have been floating in space near the asteroid for on-board analysis. The results from these instruments will come in time.

The flyby marks the attainment of one of Rosetta’s main scientific objectives. The spacecraft will now continue to a 2014 rendezvous with its primary target, Comet Churyumov-Gerasimenko. It will then accompany the comet for months, from near the orbit of Jupiter down to its closest approach to the Sun. In November 2014, Rosetta will release Philae to land on the comet nucleus.

Photo credit: ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Note: For more information and photographs, see Rosetta Triumphs at Asteroid Lutetia

Update: The website Space.com has an interesting article about Asteroid Lutetia: Peek at Huge Asteroid Provides More Questions Than Answers

Saturday, July 24, 2010

Juno


Launching from Earth in 2011, the Juno spacecraft will arrive at Jupiter in 2016 to study the giant planet from an elliptical, polar orbit. Juno will repeatedly dive between the planet and its intense belts of charged particle radiation, coming only 5,000 kilometers (about 3,000 miles) from the cloud tops at closest approach.

Juno's primary goal is to improve our understanding of Jupiter's formation and evolution. The spacecraft will spend a year investigating the planet's origins, interior structure, deep atmosphere and magnetosphere. Juno's study of Jupiter will help us to understand the history of our own solar system and provide new insight into how planetary systems form and develop in our galaxy and beyond.

Illustration credit: NASA/JPL

Friday, July 23, 2010

NGC 5139 Omega Centauri and Saturn's F Ring


While NASA's Cassini spacecraft was pointed to study Saturn's F ring, it happened to catch a globular star cluster passing through the camera's field of view.

This movie is a concatenation of 13 images each taken about three minutes apart that show NGC 5139, or Omega Centauri. Some of the cluster's stars can even be seen through the ring's narrow Keeler Gap near the end of the movie. The cluster was in Ptolemy's star catalog but was officially discovered by Edmond Halley in 1677 and was recognized as a globular cluster by John Herschel.

This view looks toward the northern, unilluminated side of the rings from about 53 degrees above the ring plane. The stars on average were brightened by a factor of 10 relative to Saturn's rings. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 29, 2009. The view was acquired at a distance of approximately 1.2 million kilometers (746,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 57 degrees. Image scale is 7 kilometers (4 miles) per pixel.


Photo credit: NASA/JPL/Space Science Institute

Thursday, July 22, 2010

Supermassive Stars in Star Cluster R136a


Using a combination of instruments on ESO’s Very Large Telescope, astronomers have discovered the most massive stars to date, some weighing at birth more than 300 times the mass of the Sun, or twice as much as the currently accepted limit of 150 solar masses. The most extreme of these stars was found in the cluster RMC 136a (or R136 as it is more usually named). Named R136a1, it is found to have a current mass of 265 times that of the Sun. Being a little over a million years old, R136a1 is already “middle-aged” and has undergone an intense weight-loss program, shedding a fifth of its initial mass over that time, or more than fifty solar masses. It also has the highest luminosity, close to 10 million times greater than the Sun.

R136 is a cluster of young, massive and hot stars located inside the Tarantula Nebula, in one of the neighborhood galaxies of the Milky Way, the Large Magellanic Cloud, 165,000 light-years away. R136 contains so many stars that on a scale equivalent to the distance between the Sun and the nearest star there are tens of thousands of stars. Hundreds of these stars are so incredibly bright that if we were to sit on a (hypothetical) planet in the middle of the cluster the sky would never get dark.

This montage shows a visible-light image of the Tarantula nebula as seen with the Wide Field Imager on the MPG/ESO 2.2-meter telescope (left) along with a zoomed-in visible-light image from the Very Large Telescope (middle). A new image of the R136 cluster, obtained with the near-infrared MAD adaptive optics instrument on the Very Large Telescope is shown in the right-hand panel, with the cluster itself at the lower right. The MAD image provides unique details on the stellar content of the cluster.

Photo credit: ESO/P. Crowther/C.J. Evans

Update: This post has become popular, and I've noticed that some people have been looking for a comparison between our Sun and this enormous star, R136a1. The below illustration, produced by the European Southern Observatory (ESO), illustrates the size differences between R136a1 and three other stars, one of which is supposed to be similar in size to our Sun:


Illustration credit: ESO/M. Kornmesser

Wednesday, July 21, 2010

IGR J13042-1020: A Massive Black Hole in Spiral Galaxy NGC 4939


INTEGRAL has discovered hundreds of new sources in the hard X-ray range (> 20 keV). Most of these sources have an unknown nature, and multi-wavelength studies are necessary to try to classify them. This can be a challenging task since different diagnostics can lead to different classifications for the source type.

Occasionally, however, the sky is quite cooperative. The image above shows one example of a source discovered in hard X-rays by INTEGRAL: IGR J13042-1020. Multi-wavelength follow-up observations with the Swift satellite allowed the X-ray, UV, and optical counterparts to be identified. The image is a composite of the Swift/UVM2, UVW1, UVW2 observations. The small red circle and the large white circle represent the Swift/XRT soft X-ray and IBIS/ISGRI hard X-ray position, respectively. The UV/optical counterpart is the nucleus of the galaxy NGC 4939 which permits an easy identification of IGR J13042-1020 as an active galactic nucleus (AGN). The galaxy is located 140 million light-years away (at a redshift of z~0.01).

Examination of the X-ray spectra further enabled designation of the source as a probable Type 2 Seyfert AGN. These objects are powered by accretion of large amounts of material onto a central supermassive black hole. One of the characteristics of Type 2 AGN is the high absorption that can shield a significant amount of the soft X-rays, and hinders or prevents their discovery through scanning. By observing at higher energies that are unaffected by absorption, INTEGRAL has discovered dozens of such systems.

Photo credit: European Space Agency

Monday, July 19, 2010

Messier 45 - The Pleiades - by WISE


This image shows the famous Pleiades cluster of stars as seen through the eyes of WISE, or NASA's Wide-field Infrared Survey Explorer. The mosaic contains a few hundred image frames -- just a fraction of the more than one million WISE has captured so far as it completes its first survey of the entire sky in infrared light.

The Pleiades are what astronomers call an open cluster of stars, meaning the stars are loosely bound to each other and will eventually, after a few hundred million years, go their separate ways. The cluster is prominent in the sky during winter months in the constellation Taurus, when viewed from the Northern Hemisphere. Often called the Seven Sisters from Greek tradition, this cluster of stars has been named by cultures the world over: Parveen in Persian; Tianquiztli in the Aztec tradition, and Subaru in Japan.

In this infrared view of the Pleiades from WISE, the cluster is seen surrounded by an immense cloud of dust. When this cloud was first observed, it was thought to be leftover material from the formation of the cluster. However, studies have found the cluster to be about 100 million years old -- any dust left over from its formation would have long dissipated by this time, from radiation and winds from the most massive stars. The cluster is therefore probably just passing through the cloud seen here, heating it up and making it glow.

At a distance of about 436 light-years from Earth, the Pleiades is one of the closest star clusters and plays an important role in determining distances to astronomical bodies further away. This picture from WISE covers an area of 3.05 by 2.33 degrees, which is the roughly the same area on the sky that a grid of six full moons by 4.7 full moons would occupy. Most of the stars in the cluster fall within the 20-light-year-wide region shown here.

All four infrared detectors aboard WISE were used to make this mosaic. Color is representational: blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust.

Photo credit: NASA/JPL-Caltech/UCLA

Sunday, July 18, 2010

Happy Birthday


Today is the birthday for the Minister's daughter; she is two years old. As a result, we are taking a brief respite to celebrate; in the meantime, we hope you enjoy this painting by Michael Whelan, The Ultimate Sandbox, and encourage you to buy from this talented painter.

Friday, July 16, 2010

Star IRAS 13481-6124 and Nebula


This star-forming region, captured by NASA's Spitzer Space Telescope, is dominated by the bright, young star IRAS 13481-6124 (upper left), which is about twenty times the mass of our sun and five times its radius, and is surrounded by its pre-natal cocoon. It is the first massive baby star for which astronomers could obtain a detailed look at the dusty disk closely encircling it. The research provides direct evidence that massive stars do form in the same way as their smaller brethren.

From this archival Spitzer image, as well as from observations done with the APEX 12-meter sub-millimeter telescope, astronomers discovered the presence of a jet, hinting at the presence of a disk. This was then confirmed by observations made with the European Southern Observatory Very Large Telescope Interferometer.

This picture was taken with Spitzer's infrared array camera. It is a four-color composite, in which light with a wavelength of 3.6 microns is blue; 4.5-micron light is green; 5.8-micron light is orange; and 8-micron light is red. Dust appears red-orange and most stars are blue, though ones deeply embedded within dust (like IRAS 13481-6124) take on greenish-yellow tints.


Photo credit: NASA/JPL-Caltech/ESO/Univ. of Michigan
Illustration credit: ESO/L. Calçada

Notes: For more information, see Unravelling the Mystery of Massive Star Birth. This star is located roughly 10,000 light-years away in the constellation of Centaurus.

Thursday, July 15, 2010

NGC 2467


A colorful star-forming region is featured in this stunning new NASA/ESA Hubble Space Telescope image of NGC 2467. Looking like a roiling cauldron of some exotic cosmic brew, huge clouds of gas and dust are sprinkled with bright blue, hot young stars.

Strangely shaped dust clouds, resembling spilled liquids, are silhouetted against a colorful background of glowing gas. Like the familiar Orion Nebula, NGC 2467 is a huge cloud of gas - mostly hydrogen - that serves as an incubator for new stars.

This picture was created from images taken with the Wide Field Channel of the Advanced Camera for Surveys through three different filters (F550M, F660N and F658N, shown in blue, green and red respectively). These filters were selected to let through different colors of red and yellow light arising from different elements in the gas. The total aggregate exposure time was about 2,000 seconds and the field of view is about 3.5 arcminutes across. These data were taken in 2004.

Photo credit: NASA, ESA and Orsola De Marco (Macquarie University)

Note: For more information on this nebula, see Hubble Snaps Sharp Image of Cosmic Concoction

Wednesday, July 14, 2010

SN 1572 - Tycho Brahe's Supernova


This image from NASA's Wide-field Infrared Survey Explorer (WISE) takes in several interesting objects in the constellation Cassiopeia, none of which are easily seen in visible light.

The red circle visible in the upper left part of the image is SN 1572, often called "Tycho's Supernova." This remnant of a star explosion is named after the astronomer Tycho Brahe, although he was not the only person to observe and record the supernova. When the supernova first appeared in November 1572, it was as bright as Venus and could be seen in the daytime. Over the next two years, the supernova dimmed until it could no longer be seen with the naked eye. It wasn't until the 1950s that the remnants of the supernova could be seen again with the help of telescopes.

When the star exploded, it sent out a blast wave into the surrounding material, scooping up interstellar dust and gas as it went, like a snow plow. An expanding shock wave traveled into the surroundings and a reverse shock was driven back in toward the remnants of the star. Previous observations by NASA's Spitzer Space Telescope indicate that the nature of the light that WISE sees from the supernova remnant is emission from dust heated by the shock wave.

In the center of the image is a star-forming nebula of dust and gas, called S175. This cloud of material is about 3,500 light-years away and 35 light-years across. It is being heated by radiation from young, hot stars within it, and the dust within the cloud radiates infrared light.

On the left edge of the image, between the Tycho supernova remnant and the very bright star, is an open cluster of stars, King 1, first cataloged by Ivan King, an astronomer at UC Berkeley, California. [Dr. King was at Cal when he discovered King 1; he now teaches at the University of Washington.] This cluster is about 6,000 light-years away, 4 light-years across and is about 2 billion years old.

Also of interest in the lower right of the image is a cluster of infrared-emitting objects. Almost all of these sources have no counterparts in visible-light images, and only some have been cataloged by previous infrared surveys. There are indications that they may be young stellar objects associated with a dense nebula in the area. Young stellar objects (YSOs) are stars in their earliest stages of life. YSOs are surrounded by an envelope of dust, which would explain the very red color of the sources in this image.

All four infrared detectors aboard WISE were used to make this mosaic. The image spans an area of 1.6 x 1.6 degrees on the sky or about 3 times as wide and high as the full moon. Color is representational: blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust.

Photo credit: NASA/JPL-Caltech/UCLA

Tuesday, July 13, 2010

NGC 2070 - The Tarantula Nebula


Sending chills down the spine of all arachnophobes is the Tarantula nebula, seen in this image from NASA's Wide-field Infrared Survey Explorer (WISE). Located in the southern constellation of Dorado, the Tarantula nebula is a giant star-forming region in the Large Magellanic Cloud galaxy. This irregular dwarf galaxy orbits our Milky Way galaxy. It is relatively close, in galactic terms, at about 160,000 light-years away from Earth. Its motion around the Milky Way causes compression of interstellar dust and gas at is leading edge. This has led to a huge burst of star formation, creating the Tarantula nebula.

At about 1,900 light-years across, the nebula is the largest star-forming region known in our entire Local Group of galaxies, a region encompassing over 30 galaxies, including the great Andromeda. In 1987, the closest supernova observed since the invention of the telescope was seen at the edge of the Tarantula nebula (SN1987A). It was determined to be the violent explosion of a very massive star.

All four infrared detectors aboard WISE were used to make this mosaic. The image spans an area of 1.4 x 1.2 degrees on the sky or about three times as wide as the full moon, and 2.5 times as high. Color is representational: blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust.

Photo credit: NASA/JPL-Caltech/UCLA

Monday, July 12, 2010

The Invisible Dragon


A dragon-shaped cloud of dust seems to fly out from a bright explosion in this infrared light image from the Spitzer Space Telescope.

These views have revealed that this dark cloud, called M17 SWex, is forming stars at a furious rate but has not yet spawned the most massive type of stars, known as O stars. Such stellar behemoths, however, light up the M17 nebula at the image's center and have also blown a huge "bubble" in the gas and dust that forms M17's luminous left edge.

The stars and gas in this region are now passing though the Sagittarius spiral arm of the Milky Way (moving from right to left), touching off a galactic "domino effect." The youngest episode of star formation is playing out inside the dusty dragon as it enters the spiral arm. Over time this area will flare up like the bright M17 nebula to the left of the dragon, glowing in the light of young, massive stars. The remnants of an older burst of star formation blew the bubble in the region to the far left, called M17 EB [Extended Bubble].

Photo credit: NASA/JPL-Caltech

Note: For a visible light photo of the same region, see Dragon's Lair, which also features a comparison poster of both the Spitzer image above and the visible light photo.

Sunday, July 11, 2010

Apollo 16: Footsteps Under the High Sun


The lunar module Orion landed in the Descartes highlands of the Moon on 21 April 1972. The Apollo 16 mission targeted a highland region. Originally thought to be a volcanic site, the samples returned by Apollo 16 actually indicated that the highlands of the Moon primarily consist of impact-formed rocks (breccias), a substantial scientific result.

Today's featured image is an LROC NAC image of the Apollo 16 landing site, acquired when the Sun was nearly overhead, in contrast to our previous image of the site. High Sun causes white and metallic artifacts left on the surface by John Young and Charles Duke stand out in high contrast as they reflect the noon-day sun back at LROC. The Apollo 16 astronauts churned up the lunar soil (regolith) as they moved about exploring the Moon, and this disturbed material shows up as dark lines and patches. Since the astronauts spent a fair amount of time around the Lunar Module during their three extra-vehicular activities, the bright lunar module appears to have a dark halo. The same dark halo appears around the parked rover. The labels on the image are for the Lunar Module (LM), the Lunar Roving Vehicle (LRV), the Apollo Lunar Surface Experiments Package (ALSEP), the Radioisotopic Thermoelectric Generator (RTG) that powered the ALSEP, and a line of geophones that extended W by NW from the ALSEP station.

The Constellation program identified this location as a region of interest because many important scientific questions will be answered by returning here. For example, like other Apollo landing sites, the artifacts left at the Apollo 16 site provide a record of space weathering at the site since 1972. Various planned (and accidental) long duration exposure experiments (like NASA's Long Duration Exposure Facility, experiments on Mir, etc.) have been studied, but all of these have been from facilities in low Earth orbit. Studying what decades of exposure to the lunar environment does to hardware will provide key inputs to engineers designing future systems to operate for long periods in extra-terrestrial environments (Moon, asteroids, Mars).

The Apollo 16 site also provides access to highlands regolith and rocks; highlands rocks make up about 70% of the lunar surface, and this landing site would be a great place to gather additional samples that would help us characterize the materials that comprise the majority of the lunar surface.

Photo credit: NASA/GSFC/Arizona State University

Saturday, July 10, 2010

Hurricane Alex


This view of Hurricane Alex in the western Gulf of Mexico was acquired by the Multi-angle Imaging SpectroRadiometer (MISR) instrument aboard NASA's Terra satellite just after noon Central Daylight Time on June 30, 2010. Around this time NOAA's National Hurricane Center reported Alex to be a strengthening Category 1 hurricane with maximum sustained winds of 135 kilometers per hour (84 miles per hour). By 6 p.m. Central time, Alex had been upgraded to Category 2, with maximum sustained winds of 155 kilometers per hour (nearly 100 miles per hour). The storm made landfall in northeastern Mexico, just south of the Texas border, about three hours later. High winds and rough seas further north in the Gulf halted cleanup efforts associated with the Deepwater Horizon oil spill.

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The height contrast between the clouds in the lower part of the atmosphere and the high clouds surrounding the hurricane's eye is dramatically seen in this image, which is a stereo anaglyph of a portion of the scene, created from MISR's nadir and 26-degree forward-viewing cameras. ... In this image, north is at the left. Viewing with red/blue glasses (red filter over left eye) is required to obtain the 3-D effect. The dimensions of this image are 455 by 325 kilometers (283 by 202 miles).

Photo credit: NASA/GSFC/LaRC/JPL, MISR Team

Thursday, July 8, 2010

The Planck Microwave Sky with Highlighted Galaxies


Emission from gas and dust in the plane of the Milky Way dominates this multi-color all-sky image of the microwave sky, synthesized using data spanning the full frequency range of Planck, which covers the electromagnetic spectrum from 30 to 857 GHz.

Other galactic features recognizable in the image are the Galactic Center and the giant molecular clouds of Perseus and Orion, both of which are extremely active regions of star formation.

The Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC), two small satellite galaxies of the Milky Way which are also among our Galaxy's closest neighbors are clearly visible, as is the spiral galaxy M31, or Andromeda, the largest galactic neighbor of the Milky Way. The LMC lies at a distance of about 160,000 light-years from the Sun, the SMC at about 200,000 light-years and M31 at about 2.5 million light-years. All three objects, along with the Milky Way and several other galaxies, belong to the Local Group of galaxies.

In addition, Planck's ability to detect hundreds of extragalactic radio sources, both nearby and distant, is clearly evident in this image - two examples are highlighted in the northern hemisphere. Centaurus A, the most nearby giant elliptical galaxy, located about 12 million light-years away from us, is visible just above the Galactic Plane; this galaxy has an active galactic nucleus, with intense radio emission arising from jets of plasma and lobes of high-energy particles emanating from its central, supermassive black hole. Also, 3C 273, a bright radio source located at redshift z~0.15 (corresponding to a distance of about 2 thousand million light-years away) can be seen towards the northern Galactic Pole.

Photo credit: ESA, HFI and LFI consortia

Wednesday, July 7, 2010

Planck's Microwave Sky


This multi-color all-sky image of the microwave sky has been synthesized using data spanning the full frequency range of Planck, which covers the electromagnetic spectrum from 30 to 857 GHz.

The grainy structure of the CMB [Cosmic Microwave Background], with its tiny temperature fluctuations reflecting the primordial density variations from which the cosmic web originated, is clearly visible in the high-latitude regions of the map, where the foreground contribution is not predominant.

A vast portion of the sky, extending well above and below the galactic plane, is dominated by the diffuse emission from gas and dust in the Milky Way, which shines brightly at Planck's frequencies. While the galactic foreground hides the CMB signal from our view, it also highlights the extent of our Galaxy's large-scale structure and its emission properties.

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This image is derived from data collected by Planck during its first all-sky survey, and covers about 12 months of observations.

Note: Because of the manner in which all the channels have been combined to produce this image, the colors no longer represent accurately the brightness at each frequency. The angular resolution of this image has been reduced by a factor of around three from its sharpest rendition, to better match it to a typical viewing screen.

Photo credit: ESA, HFI and LFI consortia

Note: The Minister is not happy with the definitions available on the Internet for "diffuse emission." The closest definition found says, "Emitters of radiation that covers a relatively large part of the sky are called extended sources." Diffuse in this case equates to "extended," meaning, the source of the radiation is not localized. A star is an example of a localized source of radiation; the radiation comes from a specific, discrete source. (Radiation may refer to any and/or all wavelengths of the electromagnetic spectrum.) Diffuse emission, on the other hand, refers to the emission of radiation from a source that is much broader than a localized emitter; indeed, the emissions may come from multiple sources that are either too numerous or too indistinct for scientific instruments to focus on discrete localized sources of emission. Examples of diffuse emission include nebulae and galaxies.

Tuesday, July 6, 2010

Mars Rover Curiosity with Newly Installed Wheels


Mars rover Curiosity, the centerpiece of NASA's Mars Science Laboratory mission, is coming together for extensive testing prior to its late 2011 launch. This image taken June 29, 2010, shows the rover with the mobility system -- wheels and suspension -- in place after installation on June 28 and 29.

Spacecraft engineers and technicians are assembling and testing the rover in a large clean room at NASA's Jet Propulsion Laboratory, Pasadena, California.

Curiosity's six-wheel mobility system, with a rocker-bogie suspension system, resembles the systems on earlier, smaller Mars rovers, but for Curiosity, the wheels will also serve as landing gear. Each wheel is half a meter (20 inches) in diameter.

Photo credit: NASA/JPL-Caltech

Monday, July 5, 2010

The R Coronae Australis Region


This spectacular wide field image shows the area around the star R Coronae Australis. A huge dust cloud, about eight light-years across, dominates the center of the image. The bluish reflection nebula close to R Coronae Australis is right of center and the globular cluster NGC 6723 lies to the upper-right of the nebula. Corona Australis is a tiny tiara-shaped constellation, located next to the larger constellation of Sagittarius, in the direction of the center of the Milky Way. In spite of its faintness, this southern winter constellation can be easily spotted from dark sites because of its characteristic shape and position in the sky.

Photo credit: Loke Kun Tan (StarryScapes.com); text credit: European Southern Observatory

Sunday, July 4, 2010

NGC 300 X-1



Astronomers using ESO's [European Southern Observatory] Very Large Telescope (VLT) have detected a stellar-mass black hole much further away than any other previously known. With a mass twenty times that of the Sun, this is also the second most massive stellar mass black hole ever found. The newly announced black hole lies in a spiral galaxy called NGC 300, six million light-years from Earth.

This video zooms in onto the position of the system containing the stellar-mass black hole, and finishes with an artist's impression of the system.

Video credit: ESO/Digitized Sky Survey 2/P. Crowther/L. Calçada

Saturday, July 3, 2010

Spiral Metamorphosis



But it seems likely that in a mere 3 billion years, our neighboring galaxy Andromeda and the Milky Way will fall together and have a close collision. They will likely merge and be reborn as a single giant elliptical galaxy over the course of another billion years or so. How might this metamorphosis play out and what might you see if you looked up at night over the next 4 billion years! The space between stars is so vast compared to their size that during a galaxy collision no individual stars actually collide with one another. So our sun and its family of planets will be taking a passive but exciting ride through the pair of coalescing galaxies and take on a spectacular view of the unfolding disaster in relative safety.

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The view from far reveals an exquisite ballet of mutual annihilation and transformation into an elliptical galaxy. The Milky Way is seen coming in from the bottom in a face-on and edge-on view. After the interaction, long tidal tails of stars are flung out in open spiral patterns from both galaxies by the strong gravitational tides during the interaction. While separating, the two galaxies develop detailed spiral structure and then fall back for a second collision finally to merge. The mutual annihilation of the two galaxies leads to a big splash showing up as a complicated system of loops and ripples that represent turning points of stellar orbits. The two galaxies finally settle down into a single elliptical galaxy surrounded by remnant debris of their violent interaction.

Video credit: John Dubinski & John Kameel Farah; Text credit: John Dubinski