April 6, 2020

26.07.11: Naming P4; A Humble Proposal.

The many worlds of Pluto! (Credit: NASA/HST/SETI Institute).

By now, you’ve heard the news and read the tweets; Pluto has a fourth moon to accompany Charon, Nix, & Hydra. The discovery announcement came last week from a team of astronomers led by the SETI Institutes’ Mark Showalter utilizing the Hubble Space Telescope. The observation campaign is part of an ongoing effort to survey the environs of Pluto in anticipation of NASA’s New Horizons flyby in July of 2015. [Read more...]

17.05.11: A “Cosmic Hand.”

Pulsar PSR B1509-58. (Credit: NASA/Chandra/CXC/SAO/P. Slane et al.)

“Wow…” Of course, this word often applies itself to the jaw-dropping field of astronomy… but the picture above really merits it. The image was snapped by the Chandra X-ray observatory. It displays pulsar PSR B1509-58 within a hand-shaped nebula located about 17,000 light years distant. [Read more...]

08.05.11: The Zooniverse & the Dawn of Citizen Science.

Hubble zooms in on Hanny’s Voorwerp. (Credit: NASA/STScl).

Galaxy Zoo. Moon Zoo. Old Weather. From galaxy classification to crater counting, citizen science is growing and expanding in a way that no one would have dreamed a decade ago. Like social media in general, scientific information is becoming something that people interact with and share rather than simply consume…and nowhere is this more evident than in the Zooniverse. [Read more...]

How Far? Measuring Astronomical Distances.

You hear it at every star party. It’s probably the next biggest question right behind “is there life out there,” and “can you really see the flag the astronauts left on the moon with that thing?” Just how do we know how far away things are in the universe? After all, men have never ventured beyond the Moon; and it has only been in the past half century that we have sent embassaries on trajectories that will escape our solar system… just how do we measure these enormous distances with any confidence?

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20.02.11: A Snapshot of a Primordial Galaxy.

When it comes to the Hubble Space Telescope, the hits just keep on a’ comin’… earlier this year, researchers pushed the refurbished telescope to its limits, revealing what may prove to be most distant galaxy (or indeed object) yet seen. At 13.2 light years distant, the smudge pictured above would have been from a time when the universe was only about 500 million years old.

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Review: The Journey to Palomar.

Any groundbreaking construction project has its own unique tale, and the ascent of some of the great telescopes of the world is no exception. This week, we look at PBS’s landmark documentary, The Journey to Palomar, the story of a man and the rise of American astronomy to pre-eminence on the world scene.

George Ellery Hale was a genius who, like many before or since, was nearly driven to madness for his visionary efforts. Palomar traces the pattern he established for undertaking huge observatory construction projects, starting with his first goal that established a precedent for all others; the construction of Yerkes Observatory. The crown gem of the facility was the 40” inch Yerkes refractor, still the largest of its kind used for scientific research to this day. Yes, we know the French built a 49” refractor for the Great Paris Exhibition in 1900, but that beast proved unusable! The Yerkes refractor also marked an end for an era of 19th century astronomy; a larger refractor will probably never be built. An almost as revolutionary breakthrough was the moveable floor designed to bring the observer up to the eyepiece; this floor collapsed once shortly after construction. The film also quotes Simon Newcomb’s now famous remark that “We are probably nearing the limit of our knowledge in terms of astronomy” when in fact, the voyage had yet to really have begun!

A perfectionist, Hale was on a lifelong quest to build larger and larger instruments. This pursuit drove him westward to found the Mount Wilson observatory in California. With funding from the Carnegie Institution, ground was broken in 1904 and first light was achieved in 1908. The observatories built by Hale displayed a fundamental shift in thinking; it was slowly becoming realized that not only the instrument, but the site selected was crucial to astronomical success. Hale’s observatories were not just lone instruments, but research complexes dedicated to science and astronomy.

At the time, the 60”inch was the largest operational telescope in the world, the 72” inch Leviathan of Parsontown having fallen into disrepair. Eventually, Hale would surpass even this with 100” inch Hooker telescope, the largest and most ambitious project of its day. Completed in 1917, this scope pushed Hale to his physical and mental limits; he suffered mental fatigue, and sought relief from the immense personal pressures by sojourning in Europe. He even committed himself to several psychiatric regimens after confiding that he was suffering from hallucinations… alas, it seems that it’s never truly a great work for science and man until someone loses their mind! The Journey to Palomar explores the trials that Hale suffered through on his quest in poignant detail. The Hooker telescope itself made possible one of the great discoveries of the 20th century; Edwin Hubble’s realization that faint “nebulae” were actually galaxies beyond our own! So much for that “we know everything” guy…

But Hale wouldn’t live to see his final act play out; the construction of the 200” inch reflector atop Mount Palomar. Projects of this scale simply had no template to build off of; whole new techniques had to be devised for the figuring and polishing of the massive mirror. Construction began in 1936, and the promise of the Palomar observatory was perhaps the one great shinning light during the Great Depression. The initial glass pourings were true media events; the process itself was slow and tedious and had to be repeated several times. Corning Glass Works initially experimented with fused quartz in the initial castings but eventually settled on a new material known as Pyrex for its low thermal expansion qualities.   Hale passed on in 1938; work on the telescope was halted during World War II but the instrument that now bears his name saw first light in 1949. Footage of the final polishing process is just plain cool to watch; did you know that final polishing was done with bare fingers? Ultimately, the engineers had to pry the 200-inch away from the opticians loving hands and simply proclaim the mirror as “done”; polishing might have continued to this day! Journey to Palomar also traces the story with comments by noted scientists and authors such as astrophysicist Wendy Freedman. The Hale telescope was to a generation what Hubble and Keck are today; I vividly remember Palomar being the pinnacle of astronomy as a child of the 1970s. These days, apertures are measured in meters, and several of Hale’s masterpieces now have the modern trappings of CCD cameras and adaptive optics to remain competitive. But Hale’s visionary mastery of astronomy gave us a glimpse of what might be possible, in a field where everything may truly never be known. Do give Journey to Palomar a look for a fascinating glimpse in astronomical history. The title is available via Netflix, but the truly good news for those who read this far is its still currently up on Hulu for free viewing! Now what would Newcomb thought of that and the idea of Internet astronomy?

24.06.10: SOFIA takes flight.

A unique airborne telescope is now open for business after what has seemed like endless delays. On May 26th, NASA’s SOFIA, or the Stratospheric Observatory For Infrared Astronomy took flight to perform its first nighttime observations of the far infrared sky. And what a long road to flight it’s been… SOFIA was first proposed in the mid-90’s as a joint German DLR/NASA venture. The primary instrument consists of a 2.5 meter telescope (similar in size to Hubble) positioned perpendicular to the fuselage of a 747SP peering out a retractable cut away opening. SOFIA operates at a wavelength of 0.3 to 1600 microns, and at a cruising altitude of 41,000 feet should give diffraction limited views at wavelengths exceeding 15 microns. SOFIA needs this lofty perch to put it above 99% of the Earth’s water vapor absorbing atmosphere; at these altitudes, seeing is typically in the 2″ to 4″ arc second range. The entire project was brought back from the brink several times; in 2006, the plug was nearly pulled by Congress as the package had just neared completion! Even with cost overruns, flying telescopes aboard planes or balloons is still many times cheaper and easier than placing them into space… SOFIA is the logical predecessor of the Kuiper Airborne Observatory, a 0.9 meter IR telescope that flew aboard a modified C-141 cargo transport from 1974-95. Already, SOFIA is showing its stuff on its first observing runs, and is expected to reach a goal of 150 flights a year by 2014. Service life of SOFIA is expected to be 20 years, again far longer than that of any IR-dedicated space based telescope. SOFIA will operate out of NASA’s Dryden Aircraft Operations Facility near Palmdale, California. The 747 is a special performance (designated by SP) edition, capable of long duration flights and a range of 6,600 miles, ideally suited for the SOFIA mission. Of the 45 747SPs built, only 14 remain flying, from those flown by several Middle Eastern VIPs to the one owned by televangelist Ernest Angley (!) These are marked by the distinctive “stubby” or shortened fuselage design built to cut down weight. Doubtless, SOFIA has been the noblest use of this unique airframe yet…but hey, we are biased towards all things astronomical. You’ve come a long way, baby!


20.06.10: The Low Down on WASP-12b.

A bizarre exo-world just got stranger in the past month, but not in the way many news outlets would have you believe. WASP-12b is destined for a short life, one that we many have been fortunate enough to catch it in the middle of. The story starts in 2008, with the transiting exoplanet’s discovery by the UKs Wide Area Search for Planets (WASP) array. The primary star, WASP-12, is a yellow dwarf located 600 light years distant in the constellation Auriga. Even at that time, it was known that WASP-12b was strange; it whizzed around its star in only 26 hours and had to be sizzling. Now, follow-up measurements with the Hubble Space Telescope and its newly installed Cosmic Origins Spectrograph have indeed revealed a world in peril; at 2800° degrees Fahrenheit, WASP-12b is bloated up to three times the radius of Jupiter, although it only contains 1.4 times its mass. COS was able to identify manganese, tin, and aluminum in the spectra of the atmosphere as the planet transited its host star, using its sensitivity in the ultraviolet to pin down key measurements such as its diameter. This would put the Roche Limit of the planet well beyond what its own gravity can retain. WASP-12b is more than likely feeding material to its stellar host, an act it can’t maintain forever. Calculations show that WASP-12b will cease to exist in about 10 million years or so.  It does, however, give astronomers an opportunity to gather a spectrum for study of a hot Jupiter in action… The WASP-12b story also fueled an avalanche of bad science stories, along the lines of “Cannibal Star 600 Million Light Years Distant Consumes Planet!” as if such a star bent on evil were inbound or headed our way. Never let the facts get in the way of a good story, guys… you keep us science news bloggers employed!

12.06.10: Refurbished Hubble Catches Interstellar Speedster.

New instruments installed aboard the Hubble Space Telescope on the final repair mission are now starting to really show their stuff. Recently, astronomers revealed a new find; a massive star speeding away from the Tarantula Nebula. Located 170,000 light years distant in the Large Magellanic Cloud, this nebula is also sometimes referred to as 30 Doradus or NGC 2070. At the heart of the nebula is a star forming region known as R136. The star in question is speeding outward at an amazing 250,000 mph, or almost 70 miles a second. This would easily span the Earth-Moon distance in one hour! Already, the star has covered about 375 light years in its young estimated 1 to 2 million year long life. What accelerates a star to such a dizzying velocity? One event capable is a nearby supernova explosion. This is unlikely, because any of the siblings within 30 Dor would have been equally young. Another, more likely scenario is that this star had several early encounters with neighboring stars and promptly got flung out of the nebula. 30 Dor boasts several stars in the massive 100+ solar mass category, and is home to some of the largest stars known in the nearby universe.  First indentified in 2006 during a survey conducted at the Siding Spring Observatory in Australia, astronomers got a new view of the stellar runaway when they used it as a calibration target for the newly installed Cosmic Origins Spectrograph. They found a star perhaps 90 times the mass of our Sun unleashing furious stellar winds and carving an enormous bubble in space. COS conducts its observations primarily in the ultraviolet. Observations also confirmed that this star is one single massive entity, and not a close spectroscopic binary. Massive stars such as this are destined for a short life, ending its fusion role as a supernova and eventually leaving a remnant black hole.

Review: The Telescope by Geoff Anderson.

Few inventions are as near and dear to our hearts as that of the telescope. Before its invention, astronomy was scarcely better than its pseudo-science companion of astrology in its knowledge of predicting the universe as it truly is. In this week’s review, we’ll look at The Telescope by Geoff Anderson out from Princeton Press as it traces the history of this noble instrument, its origins, the theory of optics, and our present day understandings and the exciting realm of telescopes yet to come.Out from Princeton University Press!

Think you know everything about telescopes? The Telescope will take you through designs from classical refractors to Coudè focus complexities. This would serve as a good 101 for anyone thinking of building or even purchasing a telescope, as a lot of the optical basics are discussed. You can even skip through chapters, and the author even suggests that you don’t have to struggle through chapters on interferometry (but of course we did!) unless you really want to.

The study of how early astronomers actually functioned always personally fascinates me. We all know the discoveries of Galileo, but just how did he make those refractors in a renaissance era work shop? The absurdity of some of the focal lengths used was astounding; this was required to overcome the fringes on chromatic aberration until 2-element crown and flint objectives were perfected. And don’t forget, they had to handcraft eye-pieces, as well. Just how many modern day telescope makers do that?

The evolution of site selection and observatory construction is also discussed; it’s a generally underappreciated fact that seeing and turbulence makes up about 90% of your ultimate astronomical success. Early telescope users were content to perch their tubes on the ledge of a study window. It’s only been in the last century or so that site selection prior to observatory construction has really matured. In the modern era, the effects of encroaching light pollution also has to be accounted for. Telescopes have gone from backyard curiosities to behemoths of national significance.

The modern era of scopes is also traced, from the Hale and Keck telescopes to the Hubble Space Telescope, which is appropriately given its own chapter. The chapter “When Good Telescopes go Bad” is particularly illuminating, as it demonstrates the engineering challenges that seem to plague every great instrument. It’s been said that it’s never truly a great scientific or engineering breakthrough until someone has had a nervous breakdown, and building cutting edge telescopes is certainly a case in point.  The author also addresses the innovative methods the have been developed to squeeze as much information as possible out of every photon of light. Just think, we can know speed, direction, composition and more just from “tasting” starlight. This was first developed by the breakthrough of spectroscopy, and further refinements such as interferometry and adaptive optics have pushed the envelope even further. adaptive optics itself used to be classified, as it was used primarily to peek at Russian payloads in low-Earth orbit. Some of this technology is truly amazing; for example, did you know it’s possible to “record” a conversation in a room just by measuring via laser the vibrations imparted on the windows? To this effect, the Oval Office actually employs “shakers” on its outer panes, probably not much different than the vibrate mode on your cell phone.

A look at the key discoveries of the telescope and some of the more bizarre and unusual telescopes is also given treatment; two of our favorite are the use of liquid metal (mercury in a precisely rotated dish!) telescopes, and of course, the Laser Interferometry Gravitational wave Observatory, a “telescope” used to hunt for gravity waves.

And that’s just the beginning. The future of telescopes will see the James Webb Space Telescope, mega observatories such as the Thirty Meter Telescope (TMT) and the 100-meter OverWhelmingly large telescope (OWL) and perhaps even more exotic arrays such as the Terrestrial Planet Finder or a large crater-based instrument on the Lunar far-side.

Do give the Telescope a look if you are thinking of buying, building, or just have a passion for these grand old instruments. Telescopes represent the cutting edge of human technology, and never fail to inspire. And as astronomers, observatories are the closest thing to a cathedral to the stars that we possess!

The Great Orbiting Observatories II: The Ultraviolet.

When we last left our installment of this saga, we covered the observatories that target the visible edge of our spectrum. This is a narrow slice; a tiny sliver of what we call the electromagnetic spectrum. This week, we move into the ultraviolet, a span of the spectrum at roughly between 10 to 320 nanometers. UV from space is almost entirely absorbed by our atmosphere, and thus, if you want to observe the universe or do UV astronomy, you have to go into space to do it.

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11.05.10: Ancient Galaxy Mergers.

Astronomers may have found a cosmological missing link in the realm of galactic evolution. The early universe was a crowded place; galaxy mergers must have been much more common in the primeval universe than they are today. But studying those early collisions has been problematic; the immense distances involved over time and space mean that resolving clusters and individual stars are out of the question. Now, a team from the University of Western Ontario led by Sara Gallagher has published a study of an object which may serve as a “living fossil” of those early times; Hickson Compact Group 31. A cluster of irregular galaxies “only” 166 million light years away in the constellation Eridanus, this merger has somehow escaped coalescence over 10 billion years of cosmic history to just begin merging. “Because HCG 31 is so nearby,” Gallagher notes, “we can indentify individual star clusters.” In fact, two main components of HCG 31 approach visual magnitude +13 and have been snared by amateur instruments. HCG 31 is approximately 75,000 light years in diameter, and will probably one day form one huge elliptical galaxy. To conduct this study, Gallagher utilized time and instruments that spanned the spectrum, from Hubble in visible light to Spitzer in infrared to Galex and Swift in the ultraviolet. It is amazing that astronomers now have such capabilities in their bag of tricks at their ready disposal!

02.05.10- Star-birth in the Early Universe.

Astronomers are shedding new light across the spectrum on an old cosmological mystery. It’s well documented that the rate of star formation today is much less than what it was early on in the history of the universe; what isn’t completely understood is why. Was there simply an abundance of star forming material available, or was the process of star formation more efficient? Either trend may have a huge significance as to how the current and future evolution of the universe plays out; stars such as our Sun are metal rich and formed as a result of the recycling of cosmic material from that first primeval generation of stars. Even non-fusion sustaining bodies such as the Earth, Sandra Bullock, and your IPad owe their elemental composition largely to those original stars.  Now, a team led by Michael Cooper of the University of Arizona’s Steward Observatory is tackling the dilemma from a fresh angle. The galaxies in question are about 4 billion years old; the universe is an estimated 13.7 billion years of age. In that tender young era, the rate of observed star formation was about 10 times what we see today. Traditional surveys have looked at larger, brighter, and more easily observable galaxies in the energetic throes of star formation. But is that the best approach? This method largely ignores the vast population of fainter, harder to spot galaxies. “It is a little like studying only individuals who are seven feet tall instead of those who fall in a more common range of height,” stated Cooper. Their unique approach has been to examine a selection of average galaxies culled from 50,000 objects to study across a range of wavelengths. Instruments called into action included the Hubble and Spitzer Space telescopes as well as an array of ground-based radio telescopes. Analysis across the spectrum shows that a much greater concentration of gas and dust was available to fuel star formation than what we see today; these galaxies also really light up in the radio and infrared, as pictured above… could we be looking at snapshots resembling our galaxies’ grandparents?

21.04.10-The Puzzle of Blue Stragglers.

Astronomers may have recently solved a half a century long mystery of stellar evolution. Since the 1950’s a type of star known as  a blue straggler has stubbornly refused to fit the Hertzsprung-Russell diagram mold. These older stars should be approaching seniority, but instead burn brightly and spin energetically as if they had somehow gained mass. Most exist in globular or open clusters, and were first identified in the M3 globular cluster. The most well studied example of this stellar sub-class exist in NGC 188, a star cluster about 6,000 light years distant where 21 have been identified. Now, astronomers Robert Mathieu and Aaron Geller of the University of Wisconsin Madison have gained insight into the formation of these elusive beasties and come up with three leading hypotheses;

  1. Matter is accreted from an aging red giant star onto a main sequence companion similar to the process seen in a type IA supernova, but not as massive, causing the star to re-energize;
  2. Two lower mass stars collide, an improbable but not impossible scenario in a densely packed globular cluster;
  3. A third stellar companion perturbs the orbit of a tightly knit binary pair, causing them to merge.

These possibilities were advanced after Mathieu and Geller used observing time on the 3.5-meter WIYN telescope on Kitt Peak spanning the past decade. Studies involved NGC 188, the original “blue straggler” cluster. “These aren’t just normal stars that are straggling behind in their evolution,” stated Mathieu.” There is something unusual going on with their companions.” Computer models would suggest that door number #3 is the most likely candidate; the most logical proof that astronomers would like to have in hand would be to catch a merger in progress.  Interestingly, two known blue stragglers with white dwarf companions lie in the field of the Kepler space telescope, a plus for the accretionary camp. Will we soon have definitive evidence for the origins of these bizarre stars? Or is it perhaps a hybrid of the three models? Stay tuned…

Space Telescopes, Part I: Optical.

This weeks’ expose will kick off our four part series on orbiting space telescopes. For starters, we’ll begin with the most familiar; the optical wavelength. True, we as humans are biased towards this narrow band of the spectrum; we love to see pretty pictures that we can relate to.  But beyond this, telescopes that operate in the visual wavelengths have no less than revolutionized astronomy, as well as laid promise for perhaps giving us images of exo-Earths in our lifetimes. What follows is a rapid fire list of what was, is, and what to look for up and coming in the realm of optical astronomy in space:

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20.04.10: Hubble Smashes KBO record.

The Hubble Space Telescope has shattered yet another record; the smallest Kuiper Belt Object yet recorded. But the discovery came not from the telescope’s main optical array, but an unlikely source; its Fine Guidance Sensors. These star trackers point the HST and sample target stars 40 times a second. Using an innovative technique, a team led by Hike Schlichting sifted through 4.5 years of data to find a single 0.3 second in duration event. This is estimated to be a tiny KBO inclined about 14° degrees to the solar ecliptic. At an estimated 975 meters across and 6.8 billion kilometers distant, this object stands as the tiniest distant object ever detected. The Kuiper belt is a ring of icy material extending just beyond the orbit of Neptune out to about 55 astronomical units. At an estimated +35 magnitude in brightness, this icy body is far too small for even Hubble to see. The object was inferred indirectly by what’s known as a stellar occultation. This discovery also highlights the utility of pouring over the backlog of astronomical data generated by such platforms as Hubble. What other discoveries lay hidden it that thar’ data?

12 Amazing Moments in Science.

Let it be known that this post did indeed start with 12… whenever someone mentions the most exalted achievements of mankind, the topic usually comes around to science. Along with our art and music, we’re the only animals that will know of that routinely apply the scientific method to the universe around us. And yet, some scientific discoveries weren’t supposed to be made, and their advent catapulted us years ahead of our time, or at least had the potential to do so, if only they had been recognized. What follows is a list of surreptitious, un-authorized, or just plain awesome discoveries that gave us some key insight into the nature of reality. Just like in the Wizard of Oz, most scientists work for their entire lives just to get a brief glimpse of the man behind the curtain. Anyway, we tried to be as fair as possible and include examples from a cross-section of scientific disciplines; we also tried to include the rare but true tales alongside the ones everybody knows. If your fave didn’t make the cut, let us know; there’s certainly cyber-space for a part II! Thanks also to those intrepid readers who sent in their suggestions; you rock, as always…

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04.02.10: Pluto Re-imaged.

The most controversial planet (or do you say dwarf planet, or plutoid?) got a new look today. In a press conference, NASA researchers revealed the new “face” of Pluto; a series of images spanning 270 degrees of rotation. To complete these, astronomers scoured 384 images for 4 years using no less than 20 computers. These images were acquired from the Hubble Space Telescope’s Advanced Cameras for Surveys, and span a period from 2002-03. Even under the most favorable conditions, Pluto is a tough target; at around 0.1” arc seconds in size, Pluto only covers only a few pixels even in the best cameras and telescopes. The images are in true color, and present a tan-ish to grey world that is perhaps Mars-like in appearance. This is suggestive of a broad diversity of plutonian topography, and comparisons with the 1994 images show correlations with bright surface features, but also changes that hint at seasonal variations. Specifically, Pluto appears significantly redder and shows a magnitude variation of 0.2 magnitudes, which is surprising over a short 8 year span…Pluto takes 248 years to complete one orbit. Charon, Pluto’s large moon, was a good “color test” as it stayed the same throughout both imaging cycles, lending credence to the idea that the changes throughout were real and not an artifact.

Spectroscopic analysis reveals that Pluto is a dynamic world, covered by frozen methane and fluro-hydrocarbons. In fact, it’s suggested that the world may be a twin to Triton, Neptune’s largest moon. “Certainly, the Kuiper Belt is an amazing place,” such researcher Mike Brown, who laughed at the idea that perhaps Pluto was getting redder in anger at him due to its recent demotion. Hubble’s newly installed WFC3 camera will begin imaging Pluto over a five month period starting April 2010, in anticipation of the New Horizons flyby in 2015. And all this on today, Clyde Tombaugh’s 104th birthday! Expect those astronomy text books to be changing soon…