The scale of things

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WIKI NOTES | The Telescopio InfraRosso del Gornergrat (TIRGO) is located on the northern tower of the Kulm Hotel at Gornergrat (3,135 metres (10,285 ft) altitude) near Zermatt, Switzerland. It was a 1.5 metres (4.9 ft) Cassegrain telescope with a tip-tilt correcting secondary and optimized for infrared observations, but was decommissioned in March 2005. The telescope and related instrumentation were run by the Istituto di Radioastronomia (IRA - C.N.R.), sezione di Firenze (former CAISMI), with the assistance of the Osservatorio Astrofisico di Arcetri and the Dipartimento di Astronomia e Scienza dello Spazio of the University of Florence.

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Jungfraujoch & Gornergrat | Gallery with a load of photos from 2004 to 2013.

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^ European Extremely Large Telescope ESO trailer

European Southern Observatory has selected Cerro Armazones, 20 km from the Very Large Telescope, as the site for the E-ELT in northern Chile.

^ E-ELT and VLT sizes compared with Brandenburger Tor.

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The Lion’s Share of Galaxies | Phil Plait
Bad Astronomy | Wednesday, July 3, 2013, at 8:00 AM

The Universe is built in layers. The fundamental units, you could argue, are stars. Some are solitary (like the Sun), some orbit each other as binary stars. By the hundreds or thousands they comprise clusters, and if you have a few billion to a few hundred billion, you get a galaxy.

Our Milky Way is part of a small group of about 50 other galaxies, most of which are smallish dwarfs. The next step up from a group is a galaxy cluster, which can contain hundreds to thousands of galaxies.

One of the nearest galaxy clusters is Abell 1367, more commonly called the Leo Cluster. A search of the astronomical literature shows it’s unclear how many galaxies can be considered Leo citizens; there are at least 70 major galaxies and perhaps many more. It’s 300 million light-years away in the constellation of Leo (of course).

And it’s gorgeous. Astronomer Adam Block took an amazing image of the central region of the cluster using the 0.81 meter Schulman telescope on Mt. Lemmon in Arizona:


^ A city of galaxies: the Leo Cluster. All photos by Adam Block/Mount Lemmon SkyCenter/University of Arizona

That’s just one part of the cluster, the core; click the picture to see the whole magnificent image Adam created. As you can see, there’s one big fuzzy elliptical galaxy dominating the cluster core. That’s NGC 3842, and it sits at the center of mass of the cluster. It probably grew that large by cannibalizing other galaxies, eating them and adding to its girth.

Most of the galaxies in the cluster look yellow, even the spirals. That happens a lot in clusters. There is gas between the galaxies, and as they plow through it at high speed, attracted to each other by their mutual gravity, the gas inside the galaxies is stripped away. (The analogy I like is opening the windows in a car to air out a, um, foul odor.) If it had stayed in the galaxies, that gas would’ve gone into making new stars, so in those stripped galaxies no stars have been made in a long time. The stars we see in them are old. Blue stars don’t live long, so over time the galaxies redden.

The exception is that edge-on blue galaxy, called UGC 6697. It appears to be undergoing a burst of star formation, and that’s likely due to the gas inside the galaxy getting compressed as it passes through the cluster gas. It lies on the outskirts of the cluster (it’s superposed on the core at the moment), where the amount of gas is just enough to trigger star birth but not enough to sweep away the galaxy’s gas completely.


^ Closer view of a handful of distorted spiral galaxies in the Leo Cluster.

Surveying the rest of the image yields more wonders. Near the top is a gorgeous spiral galaxy, canted to our line of sight, along with some smaller disturbed galaxies. These look like they’ve recently suffered collisions with other galaxies, another common occurrence in the busy environment of clusters. The face-on galaxy, cut off at the top of the frame, is a complete mess. Collisions between galaxies can really play havoc on their structure … as we’ll find out in a mere 4 billion years, when our Milky Way collides and merges with the massive Andromeda galaxy.


^ Three disk galaxies, all gassed out.I also like this little trio of galaxies in the cluster. All three are spirals, but the one at the top seems to have no obvious arms (in that case it’s just called more generically a “disk galaxy”). The other two have strong bars, linear streams of stars across their nuclei. Our own galaxy is a barred spiral, though very different than these; the Milky Way is still busily churning out young stars, so our spiral arms are very obvious, and very blue.

The Leo Cluster is roughly the same distance away from the Earth as the far larger and richer Coma Cluster. Together, along with some smaller ones like the Hercules Cluster, they form the Coma Supercluster, the next layer of the hierarchy.

And it goes up from there. The Coma Supercluster, along with many others, forms a structure called the Great Wall, a vast complex hundreds of millions light-years long. It’s one of the largest structures in the entire Universe, but there are many like it.

It’s incredible, mind-numbing. The scale of the Universe crushes our sense of size, fills our capacity of awe to overflowing. I know some people despair when they think about this, but it has the opposite effect on me: I am uplifted. Not only is it wonderful enough that such things exist at all, but how astonishing is it that we can see them, study them, understand them? Perhaps not completely, of course, not yet and perhaps never in their entirety.

But we can try. And that makes us important, even at the tiny, tiny scale of this vast, vast Universe we inhabit.

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An Ultraviolet Galaxy Hunter Closes Its Eye | Phil Plait
Bad Astronomy, Wednesday, July 10, 2013, at 8:00 AM


^ NGC 6744, a spectacular spiral galaxy observed by GALEX. All photos in this article by NASA/JPL-Caltech

On June 28, NASA flipped the switch for GALEX, shutting down the highly successful astronomical observatory. This was not unexpected; the mission had a fantastic 10-year run, and given NASA’s limited budget, the funding to operate it was needed elsewhere*. It’s always sad to see a workhorse like this one put down, but it had a long and very successful life.

GALEX—the Galaxy Evolution Explorer—observed the sky in ultraviolet, a high-energy form of light. Young stars still embedded in their birth clouds pour out this kind of light copiously, and the primary goal of GALEX was to observe galaxies in the UV to determine the rate of star formation. By observing galaxies at all distances, from the local Universe to the farthest reaches of the cosmos, it would see them at different ages, allowing scientists to see how galaxies evolve over time. It was the only UV camera in space capable of doing this kind of survey.


^ Mira, a red giant star shedding material like a comet.

Along the way it made some pretty amazing observations. Galaxies are lovely in the UV, but GALEX wasn’t limited to looking just at them. It also took a peek at Mira, a red giant star just 400 light-years from Earth. The star is dying, shedding its outer layers while at the same time plowing at high speed through the thin material that lies between the stars themselves. The result is that the star looks like a comet with an extended tail, except that tail is 130 billion kilometers long. You can even see the bow shock wave, the arc in front (on the right) of the star as it rams through that interstellar material, compressing it.


^ Not a Melkot, but the Cygnus Loop.

It also looked at stars long dead: That picture above shows the Cygnus Loop, a vast structure created by the expanding debris of a long-ago exploded star, slamming into and sweeping up the gas around it. Located about 1,400 light-years away, the nebula is huge: 80 light-years across. Even at that tremendous distance, its apparent size is six to seven times that of the full Moon on the sky! The gas is compressed into tendrils and filaments hot enough to emit ultraviolet light, making it appear like an enormous jellyfish.


^ M31, the Andromeda Galaxy.

Lastly, I can’t leave this without putting up that magnificent image of the Andromeda Galaxy, our nearest big spiral galaxy neighbor in the Universe. I wrote all about this image before, so you can get your fill (Phil?) of the science there. But it’s impossible not to be awed by the sprawling complexity of the spiral arms in this gorgeous galaxy, the site of the births of countless billions of stars. Because it’s so close—about 2.5 million light-years away, our back yard as galaxies go—Andromeda is one of the best-studied objects in the sky. In the fall it’s even visible to the naked eye, a faint smudge that belies its profound nature.

I never worked with GALEX directly, but I’ve worked extensively with a different space-based UV camera, and it’s hard to see one of its brethren turned off. But the data GALEX has taken will live on in archives that will be used by astronomers for many years. And I hope that in the future there will be more and more sophisticated observatories like GALEX yet to come.

*I think the fact that NASA has to make a choice to turn off functioning missions due to budget constraints is a national embarrassment. NASA costs us very, very little and gives us so, so much. See the bottom section of this post for my editorializing on this topic.

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Just the right hour to hear pleasant music enhancing the movements of northern lights.

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La Petite Aurore | Phil Plait
Bad Astronomy | Wednesday, July 10, 2013, at 11:15 AM


^ The Little Prince watches the northern lights over Norway. I love the out-of-focus stars of the Big Dipper to the upper right; it adds a rich melancholy feel to the picture. Photo by Jean-Luc Dauvergne, used by permission

How time flies! This year is the 70th anniversary of the publishing of Antoine de Saint Exupéry’s beloved book The Little Prince. To celebrate, photographer Jean-Luc Dauvergne allowed his little figure of le petit prince to watch the northern lights flow and sway in the skies over Norway:



Lovely! And appropriate: The other day, I wrote about the B612 Foundation, dedicated to saving the Earth from asteroid impacts. They chose that name because it’s the name Saint Exupéry chose for the home asteroid of the little prince. So in a way, this is art and life imitating each other, a nice closed loop of science and beauty.

Post script: Physicist Matthew Francis wrote a short, fun essay about what the asteroid B-612 would really be like if it were real. [And an update: I messed up my French grammar! I corrected "petite" to "petit" in the text, and fixed the title, too. My thanks (merci!) to Curtis Burisch for pointing this out to me.]

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ALMA Spots a Nascent Stellar Monster
Universe Today, Jason Major | July 10, 2013


^ ALMA/Spitzer image of a monster star in the process of forming

Even though it comprises over 99% of the mass of the Solar System (with Jupiter taking up most of the rest) our Sun is, in terms of the entire Milky Way, a fairly average star. There are lots of less massive stars than the Sun out there in the galaxy, as well as some real stellar monsters… and based on new observations from the Atacama Large Millimeter/submillimeter Array, there’s about to be one more.

Early science observations with ALMA have provided astronomers with the best view yet of a monster star in the process of forming within a dark cloud of dust and gas. Located 11,000 light-years away, Spitzer Dark Cloud 335.579-0.292 is a stellar womb containing over 500 times the mass of the Sun — and it’s still growing. Inside this cloud is an embryonic star hungrily feeding on inwardly-flowing material, and when it’s born it’s expected to be at least 100 times the mass of our Sun… a true stellar monster.

< The location of SDC 335.579-0.292 in the southern constellation of Norma (ESO, IAU and Sky & Telescope)

The star-forming region is the largest ever found in our galaxy.

“The remarkable observations from ALMA allowed us to get the first really in-depth look at what was going on within this cloud,” said Nicolas Peretto of CEA/AIM Paris-Saclay, France, and Cardiff University, UK. “We wanted to see how monster stars form and grow, and we certainly achieved our aim! One of the sources we have found is an absolute giant — the largest protostellar core ever spotted in the Milky Way.”

Watch: What’s the Biggest Star in the Universe?

SDC 335.579-0.292 had already been identified with NASA’s Spitzer and ESA’s Herschel space telescopes, but it took the unique sensitivity of ALMA to observe in detail both the amount of dust present and the motion of the gas within the dark cloud, revealing the massive embryonic star inside.

“Not only are these stars rare, but their birth is extremely rapid and their childhood is short, so finding such a massive object so early in its evolution is a spectacular result.”
— Team member Gary Fuller, University of Manchester, UK

The image above, a combination of data acquired by both Spitzer and ALMA (see below for separate images) shows tendrils of infalling material flowing toward a bright center where the huge protostar is located. These observations show how such massive stars form — through a steady collapse of the entire cloud, rather than through fragmented clustering.


^ SDC 335.579-0.292 seen in different wavelengths of light.

“Even though we already believed that the region was a good candidate for being a massive star-forming cloud, we were not expecting to find such a massive embryonic star at its center,” said Peretto. “This object is expected to form a star that is up to 100 times more massive than the Sun. Only about one in ten thousand of all the stars in the Milky Way reach that kind of mass!”

(Although, with at least 200 billion stars in the galaxy, that means there are still 20 million such giants roaming around out there!)

Read more on the ESO news release here.

Image credits: ALMA (ESO/NAOJ/NRAO)/NASA/JPL-Caltech/GLIMPSE

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New Technology Telescope

WIKI NOTES | The New Technology Telescope or NTT is an Alt-Az, 3.58-metre Richey-Chretien telescope part of the European Southern Observatory and began operations in 1989. It is located in Chile at the La Silla Observatory and was an early pioneer on the use of active optics. The telescope and its enclosure developed a revolutionary design for optimal image quality.… This technology, developed by ESO, known as active optics, is now applied to all major modern telescopes, such as the Very Large Telescope at Cerro Paranal and the future European Extremely Large Telescope.

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How to Spot and Track Satellites
Universe Today, David Dickinson | July 11, 2013


^ A 10 second DSLR exposure of a bright pass of the International Space Station. (Photo by Author).

It’s a question we get all the time.

Watch the sky closely in the dawn or dusk hours, and you’ll likely see a moving “star” or two sliding by. These are satellites, or “artificial moons” placed in low Earth orbit. These shine via reflected sunlight as they pass hundreds of kilometres overhead.

Many folks are unaware that you can see satellites with the naked eye. I always make an effort to watch for these during public star parties and point them out. A bright pass of the International Space Station if often as memorable as anything that can be seen through the eyepiece. But after this revelation, “the question” soon follows- “What satellite is that?”

Welcome to the wonderful and highly addictive world of satellite tracking. Ground observers have been watching the skies since Sputnik 1 and the first satellite launch in October 1957. Armies of dedicated volunteers even participated in tracking the early launches of the Space Age with Operation Moonwatch.


^ Depiction of the apparent motion of a typical satellite overhead with respect to the observer. (Graphic created by author).

The Internet has offered a wealth of information for satellite hunters. Every time I write about “how to spot the ISS,” someone amazes me with yet another new tracker App that I hadn’t heard of. One of my favorites is still Heavens-Above. It’s strange to think that we’ve been visiting this outstanding website daily for a decade and a half now. Heavens-Above specializes in satellites, and will show you a quick listing of passes for brighter satellites once configured with your location. A nifty “quick check” for possibly resolving a mystery satellite is their link for “Daily Predictions for brighter satellites” Which will generate a list of visible passes by time.


^ Screenshot of a typical list of bright satellite passes from Heavens-Above filtered by brightness, time and location.

Looking at the time, direction, and brightness of a pass is crucial to satellite identification. No equipment is needed to start the hunt for satellites tonight, just a working set of eyes and information. We sometimes use a set of Canon image-stabilized 15x 45 binoculars to hunt for satellites too faint to see with the naked eye. We’ve seen the “Tool Bag” lost during an ISS EVA a few years back, as well as such “living relics” of the early Space Age as Canada’s first satellite Alloutte-1, and the Vanguards (Yes, they’re STILL up there!) using binocs.


^ A comparison of typical satellite orbits. (Credit: Cmglee, Geo Swan graphic under a Creative Commons Attribution -Share Alike 3.0 unported license).

The trick to catching fainter satellites such as these is to “ambush” them. You’ll need to note the precise time that the selected satellite is going to pass near a bright star. Clicking on a selected satellite pass in Heavens-Above will give you a local sky chart with a time-marked path. I use a short wave portable AM radio tuned to WWV out of Fort Collins, Colorado for an accurate audible time signal. Just sit back, listen to the radio call out the time, and watch for the satellite to pass through the field of view near the target star.

Another great site for more advanced trackers is CALSky. Like Heavens-Above, CALSky will give you a customized list for satellite passes over your location. One cool extra feature on CALSky is the ability to set alerts for passes of the ISS near bright planets or transiting the Sun or Moon. These are difficult events to capture, but worth it!


^ The International Space Station transiting the Moon as captured by Mike Weasner from Cassiopeia Observatory in Arizona.

A great deal of what’s up there is space junk in the form of discarded hardware. Many satellites are on looping elliptical orbits, only visible to the naked eye when they are near perigee. Many satellites are located out at geosynchronous or geostationary orbits 35,786 kilometres distant and are invisible to the naked eye all together. These will often show up as streaks in astrophotos. An area notorious for geosynchronous satellites exists near the direction of M42 or Orion Nebula. During certain times of year, satellites can be seen nearby, nodding slowly north to south and back again. Around the March and September equinox seasons, geostationary satellites can be eclipsed by the shadow of the Earth. This can also cause communications difficulties, as many geo-sats also lie sunward as seen from the Earth around these times of year.

Probably one of the simplest satellite trackers for casual users is Space Weather’s Satellite Flybys page. North American users simply need to enter a postal code (worldwide users can track satellites via entering “country-state-city”) and a list of passes for your location is generated.

It’s a basic truism of satellite tracking that “aircraft blink; satellites don’t”. Know, we’re going to present an exception to this rule.

Some satellites will flash rhythmically due to a tumbling motion. This can be pretty dramatic to see. What you’re seeing is an expended booster, a cylinder tumbling due to atmospheric drag end-over-end. Some satellites can flash or flare briefly due to sunlight glinting off of reflective surfaces just right. Hubble, the ISS and the late NanoSail D2 can flare if conditions are just right.

The most dramatic of these are Iridium flares. The Iridium constellation consists of 66 active satellites used for satellite phone coverage in low-Earth orbit. When one of their three refrigerator-sized antennas catch the Sun just right, they can flare up to magnitude -8, or 40 times brighter than Venus. CALSky and Heavens-Above will also predict these events for your location.

Didn’t see a predicted satellite pass? Light pollution or bright twilight skies might be to blame. Keep in mind, passes lower to the horizon also fall prey to atmospheric extinction, as you’re looking through a thicker layer of the air than straight overhead. Some satellites such as the ISS or the USAF’s X-37B spy space plane even periodically boost or modify their orbits, throwing online prediction platforms off for a time.

More advanced satellite trackers will want to check out Celestrak and SAT-Flare Tracker 3D.


^ A screenshot example of TLE’s for the ISS & Tiangong-1 from Celestrak.

I use a free tracking platform created by Sebastian Stoff known as Orbitron. Orbitron lets you set your observing location and tailor your view for what’s currently over head. You can run simulations and even filter for “visual only” passes, another plus. I also like Orbitron’s ability to run as a stand-alone system in the field, sans Internet connection. Just remember, for it to work properly, you’ll need to periodically update the .txt file containing the Two-Line Element (TLE) sets. TLE’s are data element sets that describe the orbital elements of a satellite. Cut and paste TLEs are available from Heavens-Above and Celestrak.


^ Orbitron screenshot for visible satellites using ‘radar’ mode… there’s lots up there! (Credit: Orbitron).

For serious users, NORAD’s Space-Track is the best site for up-to-date TLEs. Space-Track requires a login and user agreement to access, but is available to satellite spotters and educators as a valuable resource. Space-Track also hosts a table of upcoming reentries, as does the Aerospace Corporation’s Center for Orbital & Reentry Debris Studies.

The SeeSat-L mailing list is also an excellent source of discussion among satellite trackers worldwide. Increasingly, this discussion is also moving over to Twitter, which is ideal for following swiftly evolving action in orbit. @Twisst, created by Jaap Meijers,will even Tweet you prior to an ISS pass!

And there’s always something new or strange in the sky for the observant. Satellites such as those used in the Naval Ocean Surveillance System (NOSS) were launched in groups, and are eerie to watch as they move in formations of 2 or 3 across the sky. These are difficult to catch, and all three of our sightings thus far of a NOSS pair have been surreptitious. And we’ve only had the camera ready to swing into action once to nab a NOSS pair;


^ A NOSS pair captured by the author. The multi-colored trail to the left of the path is an aircraft. Note a bit of “jitter” at the beginning of the exposure- I had to swing the camera into action quickly!

Another bizarre satellite to catch in action is known as the Cloud-Aerosol LiDAR & Infrared Pathfinder Satellite for Observations, or CALIPSO. Part of the “afternoon A-Train” of sun-synchronous Earth observing satellites, you can catch the green LiDAR flashes of CALIPSO from the ground with careful planning, just as Gregg Hendry did in 2008-2009:


^ A CALIPSO LiDAR pass imaged by Gregg Hendry in 2008. My Hendry mentions that, “The hollow nature of the spots is likely due to some spherical aberration in the camera lens coupled with imperfect focus, and is not representative of the laser beam’s optical quality.” (Credit: Gregg Hendry, used with permission).

NASA even publishes a prediction table for CALIPSO lidar passes. I wonder how many UFO sightings CALIPSO has generated?


^ Artist’s depiction of the A-Train constellation of Earth-Observing satellites. (Credit: NASA).

And speaking of photography, it’s easy to catch a bright pass such as the ISS on camera. Shooting a satellite pass with a wide field is similar to shooting star trails; just leave the shutter open for 10-60 seconds with a tripod mounted camera. Modern DSLRs allow you to do several test exposures prior to the pass, to get the ISO, f/stop, and shutter speed calibrated to local sky conditions.

You can even image the ISS through a telescope. Several sophisticated rigs exist to accurately track and image the space station through a scope, or you could use our decidedly low-tech but effective hand-guided method;



And that’s a brief overview of the exciting world of sat-spotting… let us know of your tales of triumph and tragedy as you sleuth out what’s going on overhead!

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Hubble Confirms Exoplanet Has a Blue Atmosphere
Universe Today, Nancy Atkinson | July 11, 2013


^ Artist’s impression of the deep blue planet HD 189733b. Credit: NASA/ESA.

Since its discovery in 2005, exoplanet HD 189733b has been one of the most-observed planets orbiting another star, as its size, compact orbit, and proximity to Earth has made it a relatively easy target — as extrasolar planets go. From previous studies, astronomers thought the planet may have an enticing blue-sky atmosphere. Now, further examinations with the Hubble Space Telescope have confirmed this planet really does harbor an azure blue atmosphere, very similar to Earth’s ocean blue color.

But this is no ‘pale blue dot’ ocean world. It is a huge gas giant orbiting very close to its host star. It gets blasted with X-rays from its star — tens of thousands of times stronger than the Earth receives from the Sun — and endures wild temperature swings, reaching scorching temperatures of over 1,000 degrees Celsius. Astronomers say it likely rains glass – sideways — in howling 7,000 kilometer-per-hour winds.

Nope, not a place you’d want to visit.

But the new Hubble observations of its color are the first time an exoplanet’s color has been measured and confirmed. The astronomers measured how much light was reflected off the surface of HD 189733b — a property known as albedo.

“This planet has been studied well in the past, both by ourselves and other teams,” says Frédéric Pont of the University of Exeter, UK, co-author of a new paper. “But measuring its colour is a real first — we can actually imagine what this planet would look like if we were able to look at it directly.”

HD 189733b is a Jupiter-sized extrasolar planet orbiting a yellow dwarf star that is in a binary system called HD 189733 in the constellation of Vulpecula, near the Dumbell Nebula, approximately 62 light years from Earth.

The planet’s blue atmosphere does not come from the reflection of a warm ocean, but is due to a hazy, turbulent atmosphere thought to be laced with silicate particles, which scatter blue light. Earlier observations using different methods have reported evidence for scattering of blue light on the planet, but these most recent Hubble observations give robust confirming evidence, the researchers said.

To make their measurements, the team used Hubble’s Space Telescope Imaging Spectrograph (STIS) to look at the system before, during, and after the planet passed behind its host star as it orbited. As it slipped behind its star, the light reflected from the planet was temporarily blocked from view, and the amount of light observed from the system dropped – not by much, about one part in 10,000 — but this was enough for STIS to determine the albedo.

“We saw the brightness of the whole system drop in the blue part of the spectrum when the planet passed behind its star,” explains Tom Evans of the University of Oxford, UK, first author of the paper. “From this, we can gather that the planet is blue, because the signal remained constant at the other colours we measured.”

Albedo is a measure of how much incident radiation is reflected. The greater the albedo, the greater the amount of light reflected. This value ranges from 0 to 1, with 1 being perfect reflectivity and 0 being a completely black surface. The Earth has an albedo of around 0.4.

According to the team’s paper, HD 189733b has an albedo of 0.4 ± 0.12.

The team says this determination will help in future studies of the atmospheres of other extra solar planets, as well as continuing the studies of one of the most-examined planets orbiting another star.

“It’s difficult to know exactly what causes the colour of a planet’s atmosphere, even for planets in the Solar System,” says Pont [5]. “But these new observations add another piece to the puzzle over the nature and atmosphere of HD 189733b. We are slowly painting a more complete picture of this exotic planet.”

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Read other details by Bad Astronomy.

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These Cubesats Could Use Plasma Thrusters to Leave Our Solar System
Universe Today, Nancy Atkinson | July 12, 2013


^ Artist concept of a 5 kg CubeSat with CubeSat Ambipolar Thruster (CAT) firing in low Earth orbit. Via Kickstarter.

Cubesats are all the rage these days: they’re usually inexpensive and quick to build and they can tag along on launches already scheduled for other things. We think of cubesats as being almost “disposable” satellites – tiny spacecraft that go into Earth orbit for a short time, do their science and then burn up harmlessly in Earth’s atmosphere. But a team of scientists have a more long-term, long-distance plan for their cubesats. Benjamin Longmier and James Cutler from the University of Michigan want to build cubesats that have tiny plasma thruster engines that could propel them into deep space, maybe even interstellar space.

They have a vision of their plasma-thruster cubesat waving as it speeds past the Voyager spacecraft at the edge of our Solar System.

They are working on what they call the CubeSat Ambipolar Thruster (CAT), a new plasma propulsion system. This thruster technology doesn’t exist all in one piece yet, but Longmeir and Cutler said they could put it together in months, with just a little funding. The CAT plasma thruster will propel a 5kg satellite into deep space, far beyond Earth orbit, at 1/1000th the cost of previous missions.

They’ve begun a $200,000 Kickstarter campaign to help fund their project. Their ideas of what these thruster propelled cubesats could do are mind-bogglingly exciting: flying through the plumes of Enceladus to look for life, studying and tagging asteroids, formation flying through Earth’s magnetosphere to learn more about solar flares and the aurora or just an interplanetary message in a bottle lasting for hundreds of millions of years in orbit around the Sun.

They think they can get a satellite up and flying within 18 months.

“The traditional funding process starts with some seed data, a large government grant and a large number of milestones and gates to go through,” said Longmier in a press release from the University of Michigan. “We’d like to leverage Kickstarter funds to compress that timeline and go from initial seed data to flight in about 18 months, a much faster time scale than is possible with traditional grants.”



The cubesats would be about as big as a loaf of bread and the thrusters – the first of its kind — would use superheated plasma directed through a magnetic field to propel the CubeSat. The duo says that with this technology, exploring interplanetary space and eventually other planets would become faster and cheaper than ever before.

While plasma rockets have been used before, they’ve only been used on big spacecraft like Deep Space 1 and DAWN. Longmier and Cutler are miniaturizing the system. Most of the thruster components have been built and have been tested individually, but they need help through Kickstarter to assemble everything into one compact thruster unit for testing the integrated components in the lab, then in Earth orbit, and then interplanetary space.

They’ve got more info on how the thrusters work on their Kickstarter page.

I dare you to tell me this isn’t exciting!

More info from the University of Michigan.

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The Hummingbird Galaxy | Phil Plait
Bad Astronomy | Monday, July 15, 2013, at 8:00 AM


^ Most hummingbirds are significantly smaller than hundreds of quadrillions of kilometers across. Click to entrochilidaenate. Photo by NASA/ESA/Hubble Heritage Team

I was pondering writing a longish post about the picture above, talking about what galaxies are, how they can physically collide, how their gravity can twist and distort their shapes into all sorts of weird things…

But seriously. That galaxy looks like a hummingbird*. What more do you need?

OK, you need a little more. For one, I’ve written quite a bit about how galaxy collisions happen, so you can read about these work here and here. The two galaxies in this collision are called NGC 2936 (the blue birdie one) and NGC 2937 (the smaller, cottonball one). Together they are known as Arp 142, named for an astronomer who observed weird, distorted galaxy pairs. They’re located about 300 million light years from Earth.

Two things really stand out to me in this picture (besides a galaxy that looks like a flippin’ hummingbird). One is the long, delicate tendril of dark, reddish dust exhumed from the previously-spiral-shaped galaxy NGC 2936, flung into a long arc across tens of thousands of light years of space. I wish we had more three-dimensional data here; I’d love to know what this structure really looks like from different angles. Since dust is very dark it blocks light coming from behind it, so this tendril is in front of the hummingbird galaxy, or perhaps embedded in it.

The other thing is that the smaller galaxy seems to have survived this collision pretty well. The shape is only mildly distorted; you can see a bit of off-centered nature to the glow of stars around the core. I suspect its more compact nature has a lot to do with that; the stars are closer together, perhaps, and the overall gravity of all those stars helped it retain its shape.

And there is one other thing. These are two very different galaxies colliding! The ex-spiral galaxy is very blue, indicating lots of star formation happened recently. Young, massive stars are blue, and when galaxies collide the gravitational interaction can cause huge clouds of gas to collapse and furiously form stars.

The other galaxy is yellower, indicating an older, more stable population—blue stars don’t live long, so a galaxy this color must not have formed stars in a long, long time. Billions of years, for sure. You can tell by looking it doesn’t have much gas and dust in it, which fits; if it had, the collision would have stirred them up, and we’d see more blue stars there as well.

Note too that you can see a handful of far more distant galaxies in the picture. The ones to the lower right are red, which is most likely due to having their light absorbed and reddened by the dust in the hummingbird galaxy; that’s another thing interstellar dust does, much like dust and haze in the air can make a sunset look red.

All in all, there’s a lot going on in this image! The hummingbird shape makes me smile, and don’t get me wrong, it’s cool. But what you’re seeing here is far more than just a shape in the clouds; you are seeing a massive collision on a cosmic scale, the collective might of a hundred billion suns, their gravity reaching out and twisting the shapes of these galaxies, stretching them like taffy, molding them like clay.

The Universe operates on the grandest of all scales, manipulating forces and energies far too large for us to grasp in our puny brains. Yet when it does so it generates beauty, and perhaps even amusement in those same brains. It helps us appreciate it, and gives us another reason to want to. And, after a while, we really can begin to grasp what the Universe is telling us.

Maybe our brains aren’t so puny after all.

* Some folks say it looks like a penguin. I can see that, but it’s silly. I mean, c’mon: a galaxy shaped like a penguin? Ridiculous.

[Allegro]

See AMANDA BAUER, astropixie

WIKI INTRO. A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image (also referred to a dioptric telescope). The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses. Although large refracting telescopes were very popular in the second half of the 19th century, for most research purposes the refracting telescope has been superseded by the reflecting telescope.

[Allegro]

Highlights mine.

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Comet ISON Among the Sparkling Stars | Phil Plait
Bad Astronomy | Wednesday, July 17, 2013, at 8:00 AM

In late November of this year, a chunk of ice and rock called comet C/2012 S1 (ISON)—colloquially just comet ISON—will plunge deep into our inner solar system, skimming the Sun’s surface just 1.2 million kilometers (700,000 miles) above the star. At that time, it may get bright enough to see with the naked eye, an event eagerly awaited by astronomers (like me)—I’ve written up all the details in earlier posts.

In the meantime, though, there’s a lot we can learn about ISON. In April, the Hubble Space Telescope was pointed at the iceball, and took this spectacular image of it among the stars:


^ Hubble saw Comet ISON while it was still well out past the orbit of Mars. Click to encomanate. Photo by NASA/ESA

This false-color picture is actually a composite of several images taken in two filters: One lets through red light (shown as red in the picture) and the other yellow-green light (shown in blue). The comet was about 600 million kilometers (360 million miles) from Earth when this picture was taken and traveling rapidly enough that it moved visibly between exposures. The composite image was made by keeping the stars steady between exposures, and then cutting out the moving comet in each image and aligning them for the final result.

Images like this are more than just eye candy; the observations help nail down the orbit of the comet to high accuracy, and look for cometary activity as well. Even though it’s far from the Sun, ISON has been pretty active, with a healthy tail. That forms when ice in the comet nucleus sublimates (turns from a solid to a gas) due to sunlight, and it’s a bit unusual to see this much of a tail from a comet so far out.

Comets are notoriously hard to predict when it comes to brightness, and there’s hope this will be a very bright one around the winter holidays. But it’s hard to say; we’ll know better, of course, as time goes on.

If you want to keep up with news about the comet, the folks at Hubble have started a Comet ISON blog, where they’ll post info and pictures. They’re also hosting a live Google+ Hangout at 20:00 UTC (4:00 p.m. EDT) today, Wednesday, July 17, 2013 where they’ll answer your questions on air.

As time goes on I’ll be keeping up with the comet as well, especially since I plan to do a lot of observing of it in the frigid winter air of Colorado. If this comet is even a fraction as bright as hoped, it’ll still be worth taking a look at. And if it does perform, well, you definitely won’t want to miss that.

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Read other details at Universe Today.

[norton ash]

Thanks, Allegro. Oh to be an ice-ball in cool dark space, hey?

[Allegro]

Thanks, Allegro. Oh to be an ice-ball in cool dark space, hey?

Cool? Brrrrr, it's cold as heck up here, and it's just a bit breezy . Put on the warmies, get a ticket. We'll wait for yah.