M31, or the Andromeda Galaxy seen in a variety of wavelengths by the Herschel and XMM-Newton space observatories. Credits: infrared: ESA/Herschel/PACS/SPIRE/J. Fritz, U. Gent; X-ray: ESA/XMM-Newton/EPIC/W. Pietsch, MPE; optical: R. Gendle
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To the naked eye, the Andromeda galaxy appears as a smudge of light in the night sky. But to the combined powers of the Herschel and XMM-Newton space observatories, these new images put Andromeda in a new light! Together, the images provide some of the most detailed looks at the closest galaxy to our own. In infrared wavelengths, Herschel sees rings of star formation and XMM-Newton shows dying stars shining X-rays into space.
During Christmas 2010, the two ESA space observatories targeted Andromeda, a.k.a. M31.
Andromeda is about twice as big as the Milky Way but very similar in many ways. Both contain several hundred billion stars. Currently, Andromeda is about 2.2 million light years away from us but the gap is closing at 500,000 km/hour. The two galaxies are on a collision course! In about 3 billion years, the two galaxies will collide, and then over a span of 1 billion years or so after a very intricate gravitational dance, they will merge to form an elliptical galaxy.
Let’s look at each of the images:
Herschel’s view in far-infrared:
Andromeda in far-infrared from Herschel. Credits: ESA/Herschel/PACS/SPIRE/J. Fritz, U. Gent
Sensitive to far-infrared light, Herschel sees clouds of cool dust and gas where stars can form. Inside these clouds are many dusty cocoons containing forming stars, each star pulling itself together in a slow gravitational process that can last for hundreds of millions of years. Once a star reaches a high enough density, it will begin to shine at optical wavelengths. It will emerge from its birth cloud and become visible to ordinary telescopes.
Many galaxies are spiral in shape but Andromeda is interesting because it shows a large ring of dust about 75,000 light-years across encircling the center of the galaxy. Some astronomers speculate that this dust ring may have been formed in a recent collision with another galaxy. This new Herschel image reveals yet more intricate details, with at least five concentric rings of star-forming dust visible.
XMM Newton’s view in X-rays
XMM Newton's view in X-Ray. Credits: ESA/XMM-Newton/EPIC/W. Pietsch, MPE
Superimposed on the infrared image is an X-ray view taken almost simultaneously by ESA’s XMM-Newton observatory. Whereas the infrared shows the beginnings of star formation, X-rays usually show the endpoints of stellar evolution.
XMM-Newton highlights hundreds of X-ray sources within Andromeda, many of them clustered around the centre, where the stars are naturally found to be more crowded together. Some of these are shockwaves and debris rolling through space from exploded stars, others are pairs of stars locked in a gravitational fight to the death.
In these deadly embraces, one star has already died and is pulling gas from its still-living companion. As the gas falls through space, it heats up and gives off X-rays. The living star will eventually be greatly depleted, having much of its mass torn from it by the stronger gravity of its denser partner. As the stellar corpse wraps itself in this stolen gas, it could explode.
Together, the infrared and X-ray images show information that is impossible to collect from the ground because these wavelengths are absorbed by Earth’s atmosphere. Visible light shows us the adult stars, whereas infrared gives us the youngsters and X-rays show those in their death throes.
A new infrared view of the star formation region Messier 8, often called the Lagoon Nebula, captured by the VISTA telescope at ESO’s Paranal Observatory in Chile. Credit: ESO/VVV
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This rich and stunning new infrared view of the Lagoon Nebula shows detail never seen before. Doesn’t it make you want to dive in for a closer look? Well, you can do just in that in a video below that zooms in on all the detail. The image was captured as part of a five-year study of the Milky Way using ESO’s VISTA telescope at the Paranal Observatory in Chile. This is a small piece of a much larger image of the region surrounding the nebula, which is, in turn, only one part of a huge survey.
The survey is called VISTA Variables in the Via Lactea (VVV), and with ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA), astronomers can scour the Milky Way’s central regions for variable objects and map its structure in greater detail than ever before.
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This image of the Lagoon Nebula (also known as Messier 8,) is part of that survey. The region which lies about 4000–5000 light-years away in the constellation of Sagittarius (the Archer).
Infrared observations allow astronomers to peer behind the veil of dust that prevents them from seeing celestial objects in visible light.
Stars typically form in large molecular clouds of gas and dust, which collapse under their own weight. The Lagoon Nebula, however, is also home to a number of much more compact regions of collapsing gas and dust, called Bok globules. These dark clouds are so dense that, even in the infrared, they can block the starlight from background stars. But the most famous dark feature in the nebula, for which it is named, is the lagoon-shaped dust lane that winds its way through the glowing cloud of gas.
Hot, young stars, which give off intense ultraviolet light, are responsible for making the nebula glow brightly. But the Lagoon Nebula is also home to much younger stellar infants. Newborn stars have been detected in the nebula that are so young that they are still surrounded by their natal accretion discs. Such new born stars occasionally eject jets of matter from their poles. When this ejected material ploughs into the surrounding gas short-lived bright streaks called Herbig–Haro objects are formed, making the new-borns easy to spot. In the last five years, several Herbig–Haro objects have been detected in the Lagoon Nebula, so the baby boom is clearly still in progress here.
By comparing 140 galaxies that had Active Galactic Nuclei with over 1200 galaxies in a "control group", the likelihood that mergers are the cause of AGN has been brought into doubt. Credit: NASA, ESA, M. Cisternas (Max-Planck Institute for Astronomy)
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The large black holes that reside at the center of galaxies can be hungry beasts. As dust and gas are forced into the vicinity around the black holes, it crowds up and jostles together, emitting lots of heat and light. But what forces that gas and dust the last few light years into the maw of these supermassive black holes?
It has been theorized that mergers between galaxies disturbs the gas and dust in a galaxy, and forces the matter into the immediate neighborhood of the black hole. That is, until a recent study of 140 galaxies hosting Active Galactic Nuclei (AGN) – another name for active black holes at the center of galaxies – provided strong evidence that many of the galaxies containing these AGN show no signs of past mergers.
The study was performed by an international team of astronomers. Mauricio Cisternas of the Max Planck Institute for Astronomy and his team used data from 140 galaxies that were imaged by the XMM-Newton X-ray observatory. The galaxies they sampled had a redshift between z= 0.3 – 1, which means that they are between about 4 and 8 billion light-years away (and thus, the light we see from them is about 4-8 billion years old).
They didn’t just look at the images of the galaxies in question, though; a bias towards classifying those galaxies that show active nuclei to be more distorted from mergers might creep in. Rather, they created a “control group” of galaxies, using images of inactive galaxies from the same redshift as the AGN host galaxies. They took the images from the Cosmic Evolution Survey (COSMOS), a survey of a large region of the sky in multiple wavelengths of light. Since these galaxies were from the same redshift as the ones they wanted to study, they show the same stage in galactic evolution. In all, they had 1264 galaxies in their comparison sample.
The way they designed the study involved a tenet of science that is not normally used in the field of astronomy: the blind study. Cisternas and his team had 9 comparison galaxies – which didn’t contain AGN – of the same redshift for each of their 140 galaxies that showed signs of having an active nucleus.
What they did next was remove any sign of the bright active nucleus in the image. This means that the galaxies in their sample of 140 galaxies with AGN would essentially appear to even a trained eye as a galaxy without the telltale signs of an AGN. They then submitted the control galaxies and the altered AGN images to ten different astronomers, and asked them to classify them all as “distorted”, “moderately distorted”, or “not distorted”.
Since their sample size was pretty manageable, and the distortion in many of the galaxies would be too subtle for a computer to recognize, the pattern-seeking human brain was their image analysis tool of choice. This may sound familiar – something similar is being done with enormous success with people who are amateur galaxy classifiers at Galaxy Zoo.
When a galaxy merges with another galaxy, the merger distorts its shape in ways that are identifiable – it will warp a normally smooth elliptical galaxy out of shape, and if the galaxy is a spiral the arms seem to be a bit “unwound”. If it were the case that galactic mergers are the most likely cause of AGN, then those galaxies with an active nucleus would be more probable to show distortion from this past merger.
The team went through this process of blinding the study to eliminate any bias that those looking at the images would have towards classifying AGN as more distorted. By both having a reasonably large sample size of galaxies and removing any bias when analyzing the images, they hoped to definitively show whether the correlation between AGN and mergers exists.
The result? Those galaxies with an Active Galactic Nucleus did not show any more distortion on the whole than those galaxies in the comparison sample. As the authors state in the paper, “Mergers and interactions involving AGN hosts are not dominant, and occur no more frequently than for inactive galaxies.”
This means that astronomers can’t point towards galactic mergers as the main reason for AGN. The study showed that at least 75% of AGN creation – at least between the last 4-8 billion years – must be from sources other than galactic mergers. Likely candidates for these sources include: “galactic harrassment”, those galaxies that don’t collide, but come close enough to gravitationally influence each other; the instability of the central bar in a galaxy; or the collision of giant molecular clouds within the galaxy.
Knowing that AGN aren’t caused in large part by galactic mergers will help astronomers to better understand the formation and evolution of galaxies. The active nuclei in galaxies that host them greatly influence galactic formation. This process is called ‘AGN feedback’, and the mechanisms and effects that result from the interplay between the energy streaming out of the AGN and the surrounding material in the center of a galaxy is still a hot topic of study in astronomy.
Mergers in the more distant past than 8 billion years might yet correlate with AGN – this study only rules out a certain population of these galaxies – and this is a question that the team plans to take on next, pending surveys by the Hubble Space Telescope and the James Webb Space Telescope. Their study will be published in the January 10 issue of the Astrophysical Journal, and a pre-print version is available on Arxiv.
Amazing Swedish view of Jan 4, 2011 partial solar eclipse, which reached its maximum – about 85%- in this stunner from Stockholm, Sweden. Poor weather and obscuring clouds momentarily relented at just the perfect time. Credit: Peter Rosen
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Millions across Earth enjoyed one of nature’s most awesomely spectacular events during today’s (Jan. 4) partial solar eclipse – the first of four set to occur in 2011. And there was nothing partial about it, for those lucky eyewitnesses where it was visible in parts of Europe, Africa and Central Asia. The eclipse reached its maximum, about 85%, in Sweden. See the maximum stunner above – taken despite pessimistic weather forecasts -by Peter Rosen in Stockholm, Sweden, with more photos from the sequence here at spaceweather.com
Probably the most technically amazing feat is the double solar eclipse captured in one image by renowned astrophotographer Theirry Legault – see below – boasting both the ISS and the Moon on the eclipsed sun’s face. Legault had traveled to the deserts of the Sultanate of Oman, near to the capital of Muscat, for this rare spectacle of nature. The ISS was calculated to be visible in a thin strip barely 11 kilometers wide, according to Astronomie Info news. The ISS transit lasted just about 1 second, speeding by at 28,000 km/sec.
See a global compilation of gorgeous eclipse photos here and comment or send us more. Update 1/6/11: this is a work in progress so please check back again.
New readers photos and eyewitness accounts added below today; as received
Click to enlarge all photos
First up: Double Solar Eclipse by renowned astrophotographer Theirry Legault in Oman
Amazing Double Solar Eclipse with the ISS and the Moon captured in one image in the deserts of the Sultanate of Oman. Credit: Theirry Legault
Check out this exciting gallery of images contributed by eclipse watchers from multiple locations around the world, on Flickr
Composition of 8 different exposures between 8.10 and 9.18 (local) recorded with solar filter and added to a unfiltered picture at the beginning of sequence. Taken with a Sony DSCW-1 with 35mm equivalent focal length. Credit: Marco Di Lorenzo, Pescara, Italy
Here is a collection of images and an eyewitness report sent to me by Marco Di Lorenzo, in Pescara, Italy
Filtered and unfiltered views at 9.11 local time. Credit: Marco Di Lorenzo
Marco writes; Pescara is located at 42.467°N and 14.225°E, about in the center of Italy on the Adriatic sea. I chose my location at the new pedestrian bridge because it is a modern structure which offers a nice foreground and also an open, elevated viewpoint. I used a couple of cameras plus a digital video camera. All the cameras were mounted on a tripod.
The weather was cold and the situation didn’t improve in the mid morning. Illumination was comparable to a slightly foggy day. The frigid temperature didn’t encourage people to go out and check. However some people did venture out. Someone asked me some info on eclipses and how to take pictures of it – very hard indeed, especially if you use a cellular phone ! Combo of 2 pictures taken few seconds apart using solar filter and different exposure; local time was 9.11 AM, near maximum. Marco Di Lorenzo
Urijian Poernick sent these photos and description:
“Colorful Solar Eclipse” at Halley Astronomical Observatory, Heesch, The Netherlands Partial Solar eclipse and flock of birds from Heesch, The Netherlands. Credit: Urijian Poernick
The weather forecast predicted overcast skies with only a few small bright intervals in all parts of The Netherlands. Nevertheless, dozens of members of Halley Astronomical Society and visitors, including many children, challenged the cold winter weather and came together on the flat roof of Halley Astronomical Observatory in The Netherlands.
Partial Solar eclipse from Heesch, The Netherlands. Credit: Urijian PoernickAfter sunrise at 7:44 UT (8:44 local time) they all looked at a narrow opening in the cloud deck near the eastern horizon. At 8:00 UT the sun showed itself: first we saw the left horn of the eclipse and a few moments later the right one.
Due to the clouds and veils it was a very colorful eclipse, with all tints of red and yellow. After twenty minutes the sun and the moon disappeared behind the overcast skies again and they didn’t come back before the end of the eclipse (9:39 UT).
During this short period everyone could watch the eclipse through the telescope and we were all enthusiastic. It was a beautiful spectacle! www.sterrenwachthalley.nl
Gianluca Masi is the National Coordinator of Astronomers Without Borders in Italy and captured this pair of photos from partially overcast Rome, Italy. The clouds contributed to make for a delightfully smoky eclipsed sun Smoky eclipsed sun from Rome, Italy. Credit: Gianluca Masi Credit: Gianluca Masi
Edwin van Schijndel sent me this report from the Netherlands:
I made some pictures in the southwest of the Netherlands. The weather conditions were not so good in the early morning, most places were covered by clouds so we decided to move about 70 miles to the southwest from our hometown. Finally we stopped not far from the city of Bergen op Zoom and were able to see sunrise while most of the sun was covered. It was splendid!
Eclipsed sunrise from Bergen op Zoom, the Netherlands. Credit: Edwin van Schijndel
Unfortunately there came more clouds so the rising sun disappeared and we drove 20 miles to the north just before Rotterdam and the sky was more clear at this place. Again we took some pictures but the maximum covering of the sun had been a few minutes before. After all this wasn’t really a pity, we were very lucky to have seen the rising of the sun and be able to make some nice pictures of the partial eclipse. Many people in the Netherlands saw less or even nothing.
Credit: Edwin van Schijndel Credit: Edwin van Schijndel
Send us or comment more solar eclipse photos to post here. ken : [kremerken at yahoo.com]
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More Readers Photos and Eyewitness Accounts. Beautiful, Thanks ! ken
Story and Photos sent me by Stefano De Rosa. Turin, Italy
Early in the morning, I moved to a site close to Turin (Italy) where the forecast was not so bad as in my city to try to observe and photograph the partial solar eclipse. Unfortunately, when I arrived it was cloudy and foggy and so decided to go back home. Technical details: Canon Eos 1000d, F/22; 150-500mm lens @ 500mm; ISO. 1/1600 sec Turin, Italy. Credit: Stefano De Rosa
Suddenly, as I was sadly driving on the motorway, close to the city of Alessandria, noticed a little break on the clouds from my rearview mirror: I stopped the car and, after a quick set up, managed to capture the crescent Sun!
http://ofpink.wordpress.com Well, I hope you carefully looked back before hitting the brakes ! – ken Turin, Italy. Credit: Stefano De Rosa
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Story and Photos sent me by Roy Keeris, Zeist, The Netherlands
Middelkerke, The Netherlands. Credit: Roy Keeris
Me and a friend (Casper ter Kuile) wanted to see the eclipse from The Netherlands. If clouds should intervene, we planned to drive a little (max. a couple of hours) to a place with a better chance for a clear sky. During the night we checked weather forecasts and satellite images. We were pretty unsure if we would succeed in seeing the eclipse, because it was pretty cloudy, and especially the low clouds tend to be quite unpredictable. In the end we chose to drive to Middelkerke (near Oostende) in Belgium because of a clear spot approaching from the North Sea.
Middelkerke, The Netherlands. Credit: Roy Keeris
We arrived at the Belgian coast just in time before sunrise. There we witnessed the eclipse from the top of a dune. About 25 minutes after sunrise the sun appeared from behind the lower clouds, just when the eclipse was at its maximum. It was magical!
First we saw the right ‘horn’ and then the left one appeared. From then on we watched the rest of the eclipse and took many pictures. [no pics from Casper ??]
Later we heard that despite the clouds, many people in The Netherlands were able to see the eclipse. There was a long stretch with a clear zone in the clouds- near the border of Germany.
Middelkerke, The Netherlands. Credit: Roy Keeris
If they had a clear horizon, people could look underneath the clouds and were just able to see the sunrise. I could even have seen it at home from my apartment on the 13th floor! But the trip was fun. It’s always nice to hunt for the right place to be at these events.
Here are some pictures I took from Middelkerke. They were shot with a Canon 400D in combination with a Meade ETS-70 telescope and a Tamron 20-200mm lens.
Thanks – Yes the hunt is half the fun. ken
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Story and Photos sent me by Igal Pat-El, Director, Givatayim Observatory, Tel Aviv, Israel
We took some images of the Jan. 4 Solar Eclipse from the Givatayim Observatory, just near Tel-Aviv, Israel. We were pleased to have Prof. Jay Passachoff as a guest during the eclipse. We had a live broadcast in plan but we had to cancel it due to heavy rain from the first contact, therefore we closed the dome’s shutter and went to the balcony trying to take some quick photos of the eclipse.
Tel Aviv, Israel. All Photos Credit: Igal Pat-El, Givatayim Observatory.
Collage assembled by Ken Kremer
We had the portable PST Coronado CaK telescope with a Ca filter On a Alt-Az mount (we could not do any alignment due to the rain). We took about 5 images against all odds in this very dim filter, using the Orion SS II Planetary imager, all of them through the haze and clouds.
Thanks, Igal. Another good lesson learned. Take a chance. You never know what you’ll get till you try !
I’ve combined Igal’s photos into a collage for an enhanced view. ken
See more photos and a video in comments section below
Love observing the Moon? There’s a new iPhone, iPod and iPad app that will provide everything you need to know. LunarCalc shows moon phases from any date between the years 1900 and 2200. It also provides ecliptic latitude and longitude, zodiacal position, distance from Earth, and apogee and perigee dates. The iPad version also provides moonrise, moonset and culmination, percent illuminated and lunation period.
LunarCalc is available in eight languages: English, Spanish, French, Italian, German Portuguese, Russian and Japanese.
Courtesy of the app’s creator, Fabio Rendelucci, Universe Today has 3 LunarCalc apps to giveaway. The first three correct answers to the following question will win. Post your answer in the comment section.
Question: When will the next total lunar eclipse take place?
To find out more or to buy the app, search “LunarCalc” in iTunes to download it.
Opportunity rover at the SW rim of Santa Maria Crater on New Year's Eve 2010 - Sol 2466. The rover sits at the edge of the crater rim and was photographed from Mars orbit by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter. Look closely to see the rover tracks on the left as Opportunity approached the westerm rim of Santa Maria crater. Credit: NASA/JPL/University of Arizona
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“I enjoy seeing our rover again,“ says Steve Squyres in an exclusive for Universe Today. Squyres is the top scientist for the Opportunity and Spirit Mars rovers.
NASA’s Opportunity rover was just been photographed from Mars Orbit while perched at the precipice of Santa Maria crater – just meters away from the edge of the Southwest rim. The photo was taken on New Year’s Eve, Dec. 31, 2010 on Sol 2466 of the mission which has lasted nearly 7 years ! Opportunity landed on Mars on Jan. 24, 2004.
“Well, it’s always great to see images like that,” Steve Squyres just informed me after seeing the new photos of Opportunity. Squyres, of Cornell University, is the Principal Scientific Investigator for NASA’s Spirit and Opportunity Mars rovers.
“This one reminds me a lot of the first time we ever saw a rover from orbit, just after Opportunity had arrived at the rim of Victoria crater. It’s a very evocative scene, and it’s hard not to project certain things onto the rover (“valiant”, “lonely”) when you see it. Mostly, though, I just enjoy seeing our rover again.”
“The last time I laid eyes on Opportunity was about seven and a half years ago, and it’s nice getting another glimpse of her,” said Squyres.
Oblique view of Opportunity on New Years Eve 2010 from Mars Orbit. HiRISE also took an an oblique view of the same area of Mars. This image shows the view looking West, as MRO pointed off nadir 18 degrees to the West to acquire this oblique image, similar to the view out an airplane window. Credit: NASA/JPL/University of Arizona
Opportunity arrived at the western rim of Santa Maria on Dec. 16 (Sol 2451) after a long and arduous trek of some 19 km since departing from Victoria Crater over 2 years ago in September 2008.
The rover has been exploring around the western portion of Santa Maria crater since arriving and is now heading to the southeast rim which possesses deposits of hydrated minerals.
Opportunity drove some 40 meters south along the steep rim from the initial location at “Palos” Promontory and then bumped incrementally further up to the edge on Sol 2464 at a place dubbed “Wanahani”.
The rover was photographed from Mars orbit while perched at “Wanahani” on New Years Eve, Dec 31, 2010 on Sol 2466.
“We are driving the vehicle in a counterclockwise direction around Santa Maria to reach the very interesting hydrated sulfates on the other side,” according to Ray Arvidson, the deputy principal investigator for the rovers, in an interview from Washington University in St. Louis. “We’ll make 3 stops or more depending on what we see”
Simultaneously to being photographed from orbit, the rover itself was of course merrily snapping a ground level view of Santa Maria. To experience the surface eye view from Opportunity, see our photo mosaic – stitched from the raw images – to display the rovers panoramic perspective whilst gazing outwards from “Wanahani” to the cliffs of Santa Maria on Sols 2464 and 2466.
Opportunity’s surface view of Santa Maria on New Years Eve Dec 31 while being photographed overhead from Mars Orbit.
Wanahani outlook at Santa Maria Crater. Opportunity took this panaromic mosaic from “Wanhani” just meters from the crater rim on Dec 29, 2010 (Sol 2464). Note rover tracks near rim at left, relatively clean solar panel at right and numerous ejecta rocks. The rim is inclined roughly 5 degrees here. CRISM mapper results suggest water bearing materials are located at the southeastern edge of the crater rim, nicknamed “Yuma”. Portions of distant Endeavour Crater are faintly visible as bumps on the horizon in the background. Mosaic Credit: NASA/JPL/Cornell, Ken Kremer, Marco Di Lorenzo
“Opportunity is imaging the crater interior to better understand the geometry of rock layers as a means of defining the stratigraphy and the impact process, says Matt Golembek, Mars Exploration Program Landing Site Scientist at the Jet Propulsion Laboratory (JPL), Pasadena, Calif.
Santa Maria is a relatively young, 90 meter-diameter impact crater (note blocks of ejecta around the crater), but old enough to collect sand dunes in its interior.
Santa Maria Crater, located in Meridiani Planum, is about 6 kilometers from the rim of Endeavour Crater, which contains spectral indications of phyllosilicates, or clay bearing minerals that are believed to have formed in wet conditions that could have been more habitable than the later acidic conditions in which the sulfates Opportunity has been exploring formed.
Data from the CRISM mineral mapper aboard MRO data show indications of hydrated sulfates on the Southeast edge of the Santa Maria Crater at which Opportunity is planning on spending the upcoming solar conjunction. After that, Opportunity will traverse to the Northwest rim of Endeavour Crater, aided tremendously by HiRISE images like the one here for navigation and targeting interesting smaller craters along the way.
Opportunity rover at the SW rim of Santa Maria Crater on New Year's Eve 2010 - Sol 2466. The rover sits at the edge of the crater rim and was photographed from Mars orbit by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter. Look closely to see the rover tracks on the left as Opportunity approached the westerm rim of Santa Maria crater. Credit: NASA/JPL/University of Arizona
Colors are important in astronomy. They can be used to get a quick feel for the temperature of stars, map out hydrogen alpha, or even find oxygen when it gives off a distinctive green glow from the forbidden transistion. Yet thus far, all images of exoplanets have only been taken in a single color filter leaving astronomers with a flat picture and no understanding of the color of a planet. A new paper corrects this oversight while analyzing the polarization of reflected starlight to develop an understanding of the characteristics of the planet’s atmosphere.
One of the properties of light is that it often becomes polarized upon reflection. This allows for polarized sunglasses to effectively reduce glare from road surfaces because the reflection tends to polarize the light in a preferred direction. Similarly, light striking a planet’s atmosphere will have a preferred axis of polarization. The degree of polarization will depend on many factors including, the angle of incidence (corresponding to the planetary phase), the types of molecules in the atmosphere, and the color, or wavelength, of light through which the planet is observed.
The object of interest was HD189733b and observations were taken in using the UBV filters system which uses filters in the ultra-violet, blue, and green (or “visible”) portions of the spectra. They were conduced at the Nordic Optical Telescope in Spain.
To control for the variations, astronomers would need to observe the planet at several wavelengths to understand how the color was affecting the results, as well as to watch the planet for several orbits to trace how the phase impacted the observations. Presently, the authors have not gone so far as to compare various composition models against these observations as this study was largely intended to be a feasibility study at multi-wavelength polarization detection.
Results have shown that the planet is brightest in the blue portion of the spectra, a result that confirms earlier, theoretical predictions for hot Jupiters as well as tentative observational findings based on single color studies done last year. This supports the notion that the dominant mechanism of polarization is Rayleigh scattering in the atmosphere. The result of this is that the planet would likely appear to be a deep blue to the naked eye, much the same way our sky appears blue, but a much more vivid color due to the increased depth to which we would look. The observations also confirmed that polarization was greatest when the planet was near greatest elongation (as far to either side of the star as possible instead of near in front or behind when viewed from Earth) which supports that the polarization is due to scattering in the atmosphere as opposed to the starlight being initially polarized from large starspots.
Certainly, this study has demonstrated the potential for astronomers to begin exploring planetary characteristics with polarization. However, it may be some time before it becomes accepted in general use. While the findings were certainly above the background noise, there existed a significant degree of uncertainty in the measurements resulting from the faint nature of planets. Being a large, hot Jupiter, HD189733b is a strong candidate since it is close to its parent star and thus, receives a large amount of light. Using such methods for other exoplanets, more distant from their parent stars will likely prove an even more daunting task, requiring careful preparation and observations.
This flag flew to the Moon and back with the Apollo 11 crew. It's one of the many items from the history of spaceflight up for sale at an upcoming auction. Image Credit: RR Auction
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If you’re interested in owning an artifact or two from the history of spaceflight, now could be your chance to snag some up. From January 13-20, over 400 artifacts relating to the history of spaceflight will be up on the auction block at RR Auction. There’s a diverse number of different pieces, ranging from an Atlas I and II crow’s foot wrench to numerous items that flew aboard many of the Apollo missions and on Projects Mercury and Gemini.
There are even a few spare parts for the Shuttle, though it’s probably not a good idea to follow along in Johnny Cash’s footsteps; if you build a space shuttle one piece at a time, it’ll cost you more than a dime and I doubt you’ll want to fly it into space.
This auction is filled with loads of memorabilia – much of it signed by astronauts or other NASA personnel – from the Apollo missions. There is a US flag that flew with the Apollo 11 crew to the Moon and back, attached to a certificate signed by Armstrong, Aldrin and Collins. As you can imagine, this one is going to go for a lot – the bidding starts at $2500. If you drill it out so it'll fit, and with a little help from an A-daptor kit, you could have a shuttle running just like a song. Image Credit: RR Auction. Mangled lyrics credit: The Man in Black
One piece that has been getting a lot of attention – and will probably also sell for quite a lot, given that it starts out at $1000 – is the original page from the November 1969 Playboy magazine featuring topless Playmate DeDe Lind. The page was stuck to a piece of cardboard aboard Apollo 12, and traveled all the way to the Moon and back aboard the Yankee Clipper.
It’s accompanied by a certificate of authenticity from Richard Gordon, the Apollo 12 Command Module pilot, which reads in part: “This cue card, which flew with me to the moon, has been in my sole possession and part of my personal space collection since my return from the moon in 1969 aboard America’s second lunar landing mission, and it remains one of the all-time greatest Apollo era astronaut ‘Gotcha’s!’” Historic, indeed.
This photograph of the Sun, taken by the Atmospheric Imaging Assembly (AIA) instrument on NASA's Solar Dynamics Observatory reveals the faint, inner corona. At the Sun's limb, prominences larger than the Earth arc into space. Bright active regions like the one on the Sun's face at lower center are often the source of huge eruptions known as coronal mass ejections. Credit: NASA/LMSAL/SAO
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Usually the only time we can see the innermost part of the Sun’s corona is when there is a total eclipse. But now, with the Atmospheric Imaging Assembly (AIA) instrument on NASA’s Solar Dynamics Observatory and a new image processing program, scientists are getting unprecedented views of the innermost corona 24 hours a day, 7 days a week.
“The AIA solar images, with better-than-HD quality views, show magnetic structures and dynamics that we’ve never seen before on the Sun,” said astronomer Steven Cranmer from the Harvard-Smithsonian Center for Astrophysics (CfA). “This is a whole new area of study that’s just beginning.”
The Sun’s outer layer, or corona is composed of light, gaseous matter, and has two parts. The outer corona is white, with streamers extending out millions of miles from the edge of the sun. The inner corona, lying next to the red chromosphere, is a band of pale yellow.
This zoomed-in image shows how the Sun's magnetic field shapes hot coronal plasma. Photos like this highlight the ever-changing connections between gas captured by the Sun's magnetic field and gas escaping into interplanetary space. Credit: NASA/LMSAL/SAO
This outer layer of the Sun’s atmosphere is, paradoxically, hotter than the Sun’s surface, but so tenuous that its light is overwhelmed by the much brighter solar disk. The corona becomes visible only when the Sun is blocked, which happens for just a few minutes during an eclipse.
Now, with AIA, “we can follow the corona all the way down to the Sun’s surface,” said Leon Golub of the CfA.
Previously, solar astronomers could observe the corona by physically blocking the solar disk with a coronagraph, much like holding your hand in front of your face while driving into the setting Sun. However, a coronagraph also blocks the area immediately surrounding the Sun, leaving only the outer corona visible.
The AIA instrument on SDO allows astronomers to study the corona all the way down to the Sun’s surface.
Cranmer and CfA colleague Alec Engell developed a computer program for processing the AIA images above the Sun’s edge. These processed images imitate the blocking-out of the Sun that occurs during a total solar eclipse, revealing the highly dynamic nature of the inner corona. They will be used to study the initial eruption phase of coronal mass ejections (CMEs) as they leave the Sun and to test theories of solar wind acceleration based on magnetic reconnection.
The resulting images highlight the ever-changing connections between gas captured by the Sun’s magnetic field and gas escaping into interplanetary space.
This time-lapse movie shows two days of solar activity observed by the AIA instrument. Both the solar surface and dynamic inner corona are clearly visible in X-rays. Hot solar plasma streams outward in vast loops larger than Earth before plunging back onto the Sun’s surface. Some of the loops expand and stretch bigger and bigger until they break, belching plasma outward.
SDO launched in February 2010.
This video provides more information about the AIA instrument:
A new look at the Eagle Nebula by Hubble. Credit: ESA/Hubble & NASA
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There are some stellar powerhouses inside the Eagle Nebula, and Hubble has captured a collection of these hot, blue stars. These dazzling stars are an open star cluster called NGC 6611, whose fierce ultraviolet glow make the surrounding Eagle Nebula glow brightly. But there are also areas in this image that look dark and empty. Are those areas just empty? No, they are actually very dense regions of gas and dust, which obstruct light from passing through.
Hubble astronomers say that many of these dark areas may be hiding the sites of the early stages of star formation, before the fledgling stars clear away their surroundings and burst into view. Dark nebulae, large and small, are dotted throughout the Universe. If you look up to the Milky Way with the naked eye from a dark, remote site, you can easily spot some huge dark nebulae blocking the background starlight.
This region in the Eagle Nebula formed about 5.5 million years ago and is found approximately 6,500 light-years from the Earth. The cluster and the associated nebula together are also known as Messier 16.
Astronomers refer to areas like the Eagle Nebula as HII regions. This is the scientific notation for ionised hydrogen from which the region is largely made. Extrapolating far into the future, this HII region will eventually disperse, helped along by shockwaves from supernova explosions as the more massive young stars end their brief but brilliant lives.
This picture was created from images from Hubble’s Wide Field Channel of the Advanced Camera for Surveys through the unusual combination of two near-infrared filters (F775W, colored blue, and F850LP, colored red). The image has also been subtly colorized using a ground-based image taken through more conventional filters. The Hubble exposure times were 2000 s in both cases and the field of view is about 3.2 arcminutes across.
