David Dickinson, Author at Universe Today

March 31, 2013December 23, 2015 by David Dickinson

Astronomical Pranks of April Fools’ Past

A April Fools Day conjunction of Pluto & Jupiter, the likes of which you'll never see! (Credit: NASA/JPL/USGS(Jupiter) & NASA?ESA & M. Buie of the SWRI (Pluto)

The first day of April is always a traditional time for pranks and puns, and astronomers and scientists aren’t above an April Fools’ Day shenanigan or two. Hey, I gotta admit, as a freelance science journalist, even my radar will be up tomorrow as I’m sure that someone will try to slide some wowzers by the credulous media, as they always have in the past. If the aliens wanted to conquer the Earth it’s wide open to ‘em on April 1^st, I’m just sayin’. Who would believe the tweets were for real, as they landed ray guns ablaze on the White House lawn? Trust us; you won’t see such April Fools’ hi-jinks from Universe Today. If you read it here, the alien invasion is for real, and you can begin stockpiling food and ammo appropriately in the best tradition of Falling Skies.

Here are just some of the classic astronomical April Fools’ jokes perpetrated in the past:

In 1974, John Gribbin published The Jupiter Effect, claiming that a Grand Alignment of the planets would spell doomsday for the Earth on March 10^th, 1982. On April 1^st 1976, Astronomer Sir Patrick Moore made an announcement along a similar vein to BBC listeners. A rare conjunction of the planets Pluto (which was still classified as a planet at the time) & Jupiter would weaken the gravitational field of the Earth at precisely 9:47AM. This would cause the law of gravity to become temporarily suspended, and cause things to fly about. Big hint: Pluto was nowhere near the gas giant at the time. Not that it would matter or have any consequence for the Earth! Although the hoax was quickly revealed, that didn’t stop several listeners from calling in and reporting observed results from the fake Jovian-Plutonian Gravitational effect!

The first star party? Galileo shows of the sky in Saint Mark's square in Venice. Note the lack of adaptive optics. (Illustration in the Public Domain). — The first star party? Galileo shows off the sky in Saint Mark’s square in Venice. Note the lack of adaptive optics. (Illustration in the Public Domain).

Many questionable astrophysical papers have been spotted in the wild trying to sneak past the guardians-that-be over the years on & around April 1st. On April Fools’ past, we’ve learned that Schrödinger’s Cat is not alone, the supposed discovery of the “bigon” particle, and that the “non-detection of the tooth fairy” has been reported. Hey, never let it be said that science geeks lack a sense of humor. What’s especially amazing is when one of these tall tales actually makes it past the credulous media and into print!

One of our favorites hit the servers last year on March 30^th just in time to gain traction for April Fools’ Day with the cryptic title On the influence of the Illuminati in astronomical adaptive optics. OK, I’ll admit we didn’t question the veracity of the claim for oh, like, maybe a tenth of a second. For those without enlightenment into the world of Woo, the Illuminati are purported to be the shadow cult organization going back to the Middle Ages that’s supposed to be behind, well, every nefarious plot in modern society. “They put the eye over the pyramid on the back of a dollar bill, man…” as some true believers will claim. And while they didn’t have adaptive optics technology way back in Galileo’s time, the mock study does assert a tenuous link between the Illuminati and the “astronomical rise” of Brittany Spears and Lady Gaga.

Phobos (above) and Diemos (bottom) closeup; no Martian construction projects noted. (Credit: NASA). — Phobos (above) and Deimos (bottom) close up; no Martian construction projects noted. (Credit: NASA).

Are Martians secretly hollowing out a base on the Moons of Barsoom? The Moons of Mars were also the setting for an April Fools’ prank in 1959. The Martian moons are bizarre in their own right. Orbiting at 6,000 & 20,060 kilometres above the surface of the Red Planet, Phobos & Deimos are almost certainly captured asteroids. In fact, Phobos orbits its primary closer than any other moon in the solar system. Phobos will crash into Mars millions of years in the future.

The hoax was perpetrated when Walter Scott Houston, posing as Dr. Arthur Hayall of the fictitious University of the Sierras made a claim in the Great Plains Observer that Phobos & Deimos were in fact artificial satellites. Though the joke ran its course, the idea has cropped up in fringe circles over the years. Russian scientist Iosif Shklovsky made a similar allusion years later, asserting that the low density of Phobos indicated that was hollow (!) Mariner 9 returned the first close-up views of Phobos in 1971, showing a decidedly asteroid-looking appearance. Of course, this hasn’t stopped the likes of folks like Richard Hoagland (he of the face on Mars) from resurrecting the outlandish claim, all of which started as a practical joke. And of course, with the advent of the Internet, you don’t have to wait until April 1st to receive modern day hoax emails proclaiming “MARS WILL APPEAR AS BIG AS THE FULL MOON!!!” which now apparently happens every August.

A moon for Mercury... (or not!) (Credit: NASA/Johns Hopkins University/APL/Carnegie Institution of Washington). — A moon for Mercury… (or not!) (Credit: NASA/Johns Hopkins University/APL/Carnegie Institution of Washington).

Spurious moons are apparently the “low-hanging fruit” of astronomical April Fools’ pranks. In 2012, an image of a purported moon of the planet Mercury’s as discovered by the MESSENGER spacecraft appeared in the JPL Photojournal. The captioning declared the moon had been named Caduceus and was 70 metres in diameter. Perhaps such a prank is appealing because there’s nothing immediately outlandish about the idea. New moons get discovered periodically on first reconnaissance missions past planets. For a brief time in 1974, Mariner 10 project scientists did indeed think they had discovered a Mercurial moon. Reading on through the press release, however, revealed that a collision course of MESSENGER with the moon was set to cause it to “arrive at Earth by 2014.” The “moon” also bared a suspicious resemblance to the asteroid 243 Ida as seen by the Jupiter-bound Galileo spacecraft in 1993.

Some April Fools’ hoaxes have presented ideas that have actually gained scientific traction in reality over the years. On March 31^st, 2005, NASA’s Astronomy Picture of the Day website contained the teaser “Water on Mars!” for its next presentation to follow on the next day. A flurry of discussion followed; was there a discovery from the Spirit & Opportunity rovers forthcoming? We should’ve checked the calendar first. The next day, APOD featured water… in a glass, sitting atop a Mars bar. What’s ironic is that recent announcements from the Mars Science Laboratory support the idea of ancient water on the Red Planet, so the MSL may well have had the last laugh.

Sulfate-rich sandstone imaged by Opportunity (left) and Curiousity (right). Both hint at ancient surface water on Mars. (Credit: NASA/JPL-Caltech/Cornell/MSSS). — Sulfate-rich sandstone imaged by Opportunity (left) and Curiosity (right). Both hint at ancient surface water on Mars. (Credit: NASA/JPL-Caltech/Cornell/MSSS).

The Museum of Hoaxes also hosts a list of astronomy & space-themed April Fools’ Day pranks that have been perpetrated over the years. From a Soviet space capsule landing outside of Kankakee, Illinois to life discovered on Jupiter in 1996, it’s all enshrined for the curious. One of our faves is Google’s 2004 announcement that they were accepting applications at a new research center… based on the Moon in Copernicus crater. The ability to survive “with limited access to such modern conveniences as soy low-fat lattes,” was cited as a prerequisite, but a sushi chef and two massage therapists would be on site. At least the assignment wouldn’t be totally austere!

Closeup of Copernicus crater region... note the distinct lack of soy lattes! (Photo by author). — Closeup of Copernicus crater region… note the distinct lack of soy lattes! (Photo by author).

What astronomical hi-jinks await us tomorrow as we flip our calendars over to April 1^st, 2013? Feel free to tell us here at Universe Today of your true tales of April Fools’ astronomy pranks past & present that you’ve spotted in the wild. Think twice before re-tweeting that link tomorrow, and don’t believe those reports of “nearby gamma-ray bursts of doom” or “alien invasions…” or at least, wait until you’ve seen the “greens of their eyes!”

March 27, 2013December 23, 2015 by David Dickinson

New Crater Names Approved for Mercury’s South Pole & More

Mercury's southern polar region as seen from MESSENGER. (Credit: NASA/Johns Hopkins UniversityApplied Physics Laboratory/Carnegie Institution of Washington).

Move over, Tolkien & Tryggvadóttir. Yesterday, an announcement was made that the International Astronomical Union (IAU) approved proposed names for nine new craters on the planet Mercury. The names honor deceased writers, artists and musicians following the convention established by the IAU for naming features on the innermost world.

The announcement comes as NASA’s MESSENGER spacecraft has completed mapping of the surface of Mercury earlier this month. A good majority of these features were established at Mercury’s southern polar region, one of the last areas of the planet to be mapped by MESSENGER.

The craters honored with a newly assigned moniker are:

Donelaitis, named after 18^th century Lithuanian poet Kristijonas Donelaitis, author of The Seasons and other tales and fables.

Petofi, named after 19^th century Hungarian poet Sandor Petofi, who wrote Nemzeti dal which inspired the Hungarian Revolution of 1848.

Roerich, named after early 20^th century Russian philosopher and artist Nicholas Roerich, who created the Roerich Pact of 1935 which asserted the neutrality of scientific, cultural and educational institutions during time of war.

Hurley, named after the 20^th century Australian photographer James Francis Hurley, who traveled to Antarctica and served with Australian forces in both World Wars.

Lovecraft, named after 20^th century American author H.P. Lovecraft, a pioneer in horror, fantasy and science fiction.

Alver, named after 20^th century Estonian author Betti Alver who wrote the 1927 novel Mistress in the Wind.

Flaiano, named after 20^th century Italian novelist and screenwriter Ennio Flaiano who was a pioneer Italian cinema and contemporary of Federico Fellini.

Pahinui, named after mid-20^th century Hawaiian musician Charles Phillip Kahahawai Pahinui, influential slack-key guitar player and part of the “Hawaiian Renaissance” of island culture in the 1970’s.

L’Engle, named after American author Madeleine L’Engle, who wrote the young adult novels An Acceptable Time, A Swiftly Tilting Planet & A Wind in the Door. L’Engle passed away in 2007.

Five of the newly named craters in the south pole region of Mercury (circled in red). Note that the final portion of the USGS map, although recently released, has yet to be filled in! (Credit: USGS).

The nine new crater names join 95 others named thus far. The MESSENGER surface mapping campaign has been ongoing since the spacecraft’s first flyby of Mercury in January 2008. MESSENGER entered permanent orbit around world on March 18^th, 2011.

MESSENGER missions operations engineer Ray Espiritu was instrumental in getting Pahinui’s name in the running.

“I wanted to honor the place where I grew up and still call home,” Espiritu said. ”The Pahinui crater contains a possible volcanic vent, and its name may inspire other scientists as they investigate the volcanic processes that helped to create Mercury, just as investigation of the Hawaiian volcanoes helps us understand the volcanic processes that shape Earth as we know it today.”

Pahinui Crater. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington).

Lovecraft is another interesting selection on the list. The name of the famous horror writer was in the running last month for the naming of Pluto’s moons P4 & P5, and New Horizons principle investigator Alan Stern hinted that Lovecraft may still find a home on a surface feature as New Horizons reveals Pluto & Charon in July 2015. It would be a fitting tribute to a fine writer. Could we end up with Lovecraft marking not only the solar system’s “hubs of hell” on Mercury, but its frozen outer wastelands as well?

There was more news yesterday in the realm of astrogeology and the planet Mercury. The IAU Working Group for Planetary System Nomenclature also made the distinction between features described as valles and catenae on the surface of Mercury. Catenae are described as crater chains, and MESSENGER has sufficient resolution that several valles have been revealed as such. Catenae on Mercury are named after radio astronomy observatories, while valles are named after abandoned cities of antiquity. Thus, Haystack Vallis is now Haystack Catena, Goldstone Vallis is now Goldstone Catena, and Arecibo Vallis is now Arecibo Catena, and, well, you get the idea.

Arecibo Catenae (formerly known as Arecibo Vallis) as imaged by MESSENGER in 2008. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington).

MESSENGER has proven to be a boon for planetary science. The spacecraft was launched in 2004 and took almost 7 years and 6 flyby assists (one past the Earth, two past Venus and three past Mercury) to become the first spacecraft to orbit the tiniest planet in our solar system. Mercury was first seen up close by Mariner 10 in 1974 and even then we only mapped 45% of its surface. Scientists had to wait until MESSENGER to fill in the remainder of Mercury’s map.

The next mission to Mercury isn’t until the planned arrival of the joint ESA/JAXA BepiColombo mission in 2022.

And don’t forget to watch for Mercury as it reaches greatest elongation on Easter Day low in the dawn sky. I managed to catch sight of it low to the east with binoculars for the first time this apparition this morning about 40 minutes prior to local sunrise. It’s amazing to think that ground-based professional telescopes & even amateur astronomers can actually image fuzzy details on the planet’s surface that match up with what MESSENGER is revealing!

All fascinating stuff to contemplate as we welcome the newest named craters to our ever expanding map of Mercury… now, will there ever be a Miskatonic University within the walls of Lovecraft crater?

-Explore these recently named craters and more using the USGS inactive Astrogeology Science Center.

-Also check out this animation of the south polar region of Mercury and more as imaged by MESSENGER.

March 25, 2013April 26, 2016 by David Dickinson

See Mercury at its Greatest Elongation for 2013

Mercury gives a clue to Super-Mercuries — Astronomers have found a star system with two planets like Mercury, but bigger. Our own Mercury could supply clues to their composition and formation. (Credit: NASA/Johns Hopkins University/Applied Physics Laboratory.Carnegie Institution of Washington).

A fine apparition of the planet Mercury graces the dawn skies this week, leading up to its greatest elongation from the Sun for 2013.

It seems that nearly every appearance of the planet Mercury is touted as the “best” these days. Such was the case with the inner-most world’s dusk showing early last month. Truth is, all elongations of Mercury (and Venus, for that matter) are not created equal, and visibility of each apparition isn’t the same for observers worldwide. We’ll show you why.

Mercury orbits the Sun once every 88 days. With an orbit interior to our own, it never strays far from the Sun in the sky and thus can only appear low in the dawn or dusk. Its orbit is also elliptical, with an eccentricity of 0.206, the greatest of any planet in our solar system. This means that greatest elongations can vary considerably, from 17.9° away from the Sun in the sky near perihelion of the planet to 28.7° near aphelion. And although reaching greatest elongation near aphelion means the tiny world is above the muck of the horizon, it also means it’s also intrinsically a bit fainter; Mercury can vary in brightness from magnitude -0.2 at a perihelic-elongation to half a magnitude fainter at +0.3 for an aphelic-elongation.

A comparison of elongations of Mercury as seen from the Earth at perihelion versus aphelion. (Created by the author).

But there’s more. Compounding this situation is the angle of the ecliptic, or the imaginary plane of the orbit of the Earth. Near the March equinox the ecliptic rides high in the dusk to the west and low in the dawn to the east for northern hemisphere observers. In the southern hemisphere, the reverse is true. It’s a strange sight for a northerner to head “Down Under” and watch the Sun rise in the east, transit to the north and set to the west!

The path of Mercury looking east ~45 minutes prior to sunrise from latitude 30 degrees north from March 26th through April 30th, (Created by the author using Starry Night).

Thus what may be a terrible apparition of Mercury for one hemisphere may be a grand one for another, as is the case this week. Yes, northern observers can catch the fleeting world, if they know exactly where to look for it. For observers based at longitude 40° north, Mercury will never peak above an altitude of 10° in the dawn sky. Observers based near 35° south will however see the planet reach its maximum possible elevation of over 25° degrees above the horizon.

We would qualify this as “The best dawn appearance of Mercury for 2013… as seen from the southern hemisphere.” Greatest elongations of Mercury occur in pairs, with dusk-to-dawn apparitions about 45 days apart as the planet passes between us and the Sun, followed by a longer period of about 70 days as the world loops back around behind the Sun. The orbit of Mercury is tilted about 7° with respect to our own. Otherwise, we would see a transit of the planet every inferior conjunction, as last occurred on November 8^th, 2006 and will happen next on May 9^th, 2016.

The path of Mercury from March 26th through April 26th looking east from latitude 35 degrees south ~45 minutes prior to sunrise. (Created by the author using Starry Night).

Mercury will show a maximum illumination area of 38.5” square arc seconds as seen from the Earth March 30^th on just before reaching its greatest elongation west of the Sun on March 31^st on Easter Day at 22:00 UT/18:00EDT. Through a telescope, Mercury will display a 7.7” diameter disk with a 50% illuminated “half-Moon” phase. Mercury reaches greatest elongation just 28 hours prior to aphelion which occurs on April 2^nd, the closest this has occurred date-wise since April 8^th, 2006. This won’t be matched again until March 24^th, 2020. Shining at magnitude +0.3, Mercury will then race ahead of the Earth on its inside track and will begin to gradually sink lower on successive mornings in early April. The morning of April 8^th may well offer the last good chance to spy the tiny world when the old crescent Moon passes just 8° degrees north of the planet within two days of reaching New phase on April 10^th. Mercury reaches superior conjunction opposite to the Earth and on the far side of the Sun on May 11^th, 2013, and will again head into the dusk skies for its next greatest eastern elongation on June 12^th.

From our Earthly vantage point, Mercury completes 3.15 orbits of the Sun a year. This means that we see 6 greatest elongations on average most years, 3 westerns (dawn) and 3 easterns (dusk). The most elongations of Mercury that you can have in a calendar year are 7, which occurred in 2011 and will happen again in 2015. It’s fascinating to think that until the advent of the Space Age, the orbit and the rough size of Mercury was all we knew about the planet. It would take the first flyby of the Mariner 10 spacecraft to give us a close up view of Mercury in 1974. The precession of the orbit of Mercury was a mystery until explained by Einsteinian physics, and still stands as one of the great proofs of general relativity. Today, we have a permanent ambassador around Mercury, NASA’s MESSENGER spacecraft. MESSENGER has mapped to world in detail, sampled its tenuous exosphere, and observed hints of ancient volcanic activity. MESSENGER will be followed by the joint European Space Agency/Japan Aerospace Exploration Agency mission BepiColombo set to launch in 2015 which will arrive at Mercury in 2022. All fascinating things to ponder as you search for the diminutive world low in the dawn skies this coming Easter weekend!

March 24, 2013April 26, 2016 by David Dickinson

Extreme Telescopes: Unique Observatories Around the World

A time exposure of the Allen Telescope Array. (Credit: Seth Shostak/The SETI Institute used with perimssion).

In 1888, astronomer Simon Newcomb uttered now infamous words, stating that “We are probably nearing the limit of all we can know about astronomy.” This was an age just prior to identifying faint nebulae as separate galaxies, Einstein’s theory of special and general relativity, and an era when a hypothetical substance called the aether was said to permeate the cosmos.

Newcomb would scarcely recognize astronomy today. Modern observatories span the electromagnetic spectrum and are unlocking the secrets of a universe both weird and wonderful. Modern day astronomers rarely peer through an eyepiece, were it even possible to do so with such bizarre instruments. What follows are some of the most unique professional ground-based observatories in operation today that are pushing back our understanding of the universe we inhabit.

The four gamma-ray telescopes in the VERITAS array. (Credit: VERITAS/The National Science Foundation).

VERITAS: Based at the Fred Lawrence Whipple Observatory in southern Arizona, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) is an observatory designed to observe high energy gamma-rays. Its array consists of four 12-metre aperture reflectors each comprised of 350 mirror scintillators. Each VERITAS array has a 3.5° degree field of view and the array has been fully operational since 2007. VERITAS has been used to study active galactic nuclei, gamma-ray bursts, and the Crab Nebula pulsar.

Looking down one of IceCube's detector bore holes. (Credit: IceCube Collaboration/NSF). — Looking down one of IceCube’s detector bore holes. (Credit: IceCube Collaboration/NSF).

IceCube: Not the rapper, IceCube is a neutrino detector in based at the Amundsen-Scott South Pole Station in Antarctica. IceCube watches for neutrino interactions by use of thousands of photomultipliers suspended up to 2.45 kilometres down into the Antarctic ice sheet. With a total of 86 detector strings completed in 2011, IceCube is currently the world’s largest neutrino observatory and is part of the worldwide Supernova Early Warning System. IceCube will also complement WMAP and Planck data and can actually “see” the shadowing effect of the Moon blocking cosmic ray muons.

The Liquid Mirror Telescope used at the NASA Orbital Debris Observatory. (Credit: NASA Orbital Debris Program Office)

Liquid Mirror Telescopes: One of the more bizarre optical designs out there in the world of astronomy, liquid mirror telescopes employ a large rotating dish of mercury to form a parabolic mirror. The design is cost effective but does have the slight drawback of having to aim directly at the zenith while a swath of sky passes over head. NASA employed a 3-metre liquid mirror telescope as part of its Orbital Debris observatory based near Cloudcroft, New Mexico from 1995-2002. The largest one in the world (and the 18th largest optical telescope overall) is the 6-metre Large Zenith Telescope in the University of British Columbia’s Malcolm Knapp Research Forest.

An aerial view of LIGO Hanford. (Credit: Gary White/Mark Coles/California Institue of Technology/LIGO/NSF). — An aerial view of LIGO Hanford. (Credit: Gary White/Mark Coles/California Institute of Technology/LIGO/NSF).

LIGO: Designed to detect incoming gravity waves caused by pulsar-black hole mergers, the Laser Interferometer Gravitational-Wave Observatory (LIGO) is comprised of a pair of facilities with one based in Hanford, Washington and another in Livingston, Louisiana. Each detector is consists of a pair of 2 kilometre Fabry-Pérot arms and measures a laser beam shot through them with ultra-high precision. Two geographically separate interferometers are needed to isolate out terrestrial interference as well as give a direction of an incoming gravity wave on the celestial sphere. To date, no gravity waves have been detected by LIGO, but said detection is expected to open up a whole new field of astronomy.

The VLBA antanna located at St. Croix in the Virgin Islands. (Credit: Image courtesy of the NRAO/AUI/NSF). — The VLBA antenna located at St. Croix in the Virgin Islands. (Credit: Image courtesy of the NRAO/AUI/NSF).

The Very Long Baseline Array: A series of 10 radio telescopes with a resolution the size of a continent, the Very Long Baseline Array (VLBA) employs observatories across the continental United States, Saint Croix in the U.S. Virgin Islands, and Mauna Kea, Hawaii. This is effectively the longest radio interferometer in the world with a baseline of over 8,600 kilometres and a resolution of under one milliarcseconds at 4 to 0.7 centimetre wavelengths. The VLBA has been used to study H2O megamasers in Active Galactic Nuclei and measure ultra-precise positions and proper motions of stars and galaxies.

LOFAR: Located just north of the town of Exloo in the Netherlands, The LOw Frequency Radio Array is a phased array 25,000 antennas with an effective collection area of 300,000 square metres. This makes LOFAR one of the largest single connected radio telescopes in existence. LOFAR is also a proof on concept for its eventual successor, the Square Kilometre Array to be built jointly in South Africa, Australia & New Zealand. Key projects involving LOFAR include extragalactic surveys, research into the nature of cosmic rays and studies of space weather.

One of the water tank detectors in Pierre Auger observatory. (Wikimedia Image in the Public Domain).

The Pierre Auger Observatory: A cosmic ray observatory located in Malargüe, Argentina, the Pierre Auger Observatory was completed in 2008. This unique instrument consists of 1600 water tank Cherenkov radiation detectors spaced out over 3,000 square kilometres along with four complimenting fluorescence detectors. Results from Pierre Auger have thus far included discovery of a possible link between some of the highest energy events observed and active galactic nuclei.

The GONG installation at the Cerro Tololo Interamerican observatory in Chile. (Credit: GONG/NSO/AURA/NSF).

GONG: Keeping an eye on the Sun is the goal of the Global Oscillation Network Group, a worldwide network of six solar telescopes. Established from an initial survey of 15 sites in 1991, GONG provides real-time data that compliments space-based efforts to monitor the Sun by the SDO, SHO, and STEREO A & B spacecraft. GONG scientists can even monitor the solar farside by use of helioseismology!

A portion of the Allen Telescope Array. (Credit: Seth Shostak/The SETI Institute. Used with permission).

The Allen Telescope Array: Located at Hat Creek 470 kilometres northeast of San Francisco, this array will eventually consist of 350 Gregorian focus radio antennas that will support SETI’s search for extraterrestrial intelligence. 42 antennas were made operational in 2007, and a 2011 budget shortfall put the status of the array in limbo until a preliminary financing goal of $200,000 was met in August 2011.

The YBJ Cosmic Ray Observatory: Located high on the Tibetan plateau, Yangbajing International Cosmic Ray Observatory is a joint Japanese-Chinese effort. Much like Pierre-Auger, the YBJ Cosmic Ray Observatory employs scintillators spread out along with high speed cameras to watch for cosmic ray interactions. YBJ observes the sky in cosmic rays continuously and has captured sources from the Crab nebula pulsar and found a correlation between solar & interplanetary magnetic fields and the Sun’s own “cosmic ray shadow”. The KOSMA 3-metre radio telescope is also being moved from Switzerland to the YBJ observatory in Tibet.

March 22, 2013December 23, 2015 by David Dickinson

Meet Hopper: A Key Player in the Planck Discovery Story

The cabinets containing the Grace Hopper Cray XE6 supercomputer. (Credit: LBNL/Dept of Energy).

Behind every modern tale of cosmological discovery is the supercomputer that made it possible. Such was the case with the announcement yesterday from the European Space Agencies’ Planck mission team which raised the age estimate for the universe to 13.82 billion years and tweaked the parameters for the amounts dark matter, dark energy and plain old baryonic matter in the universe.

Planck built upon our understanding of the early universe by providing us the most detailed picture yet of the cosmic microwave background (CMB), the “fossil relic” of the Big Bang first discovered by Penzias & Wilson in 1965. Planck’s discoveries built upon the CMB map of the universe observed by the Wilkinson Microwave Anisotropy Probe (WMAP) and serves to further validate the Big Bang theory of cosmology.

But studying the tiny fluctuations in the faint cosmic microwave background isn’t easy, and that’s where Hopper comes in. From its L2 Lagrange vantage point beyond Earth’s Moon, Planck’s 72 onboard detectors observe the sky at 9 separate frequencies, completing a full scan of the sky every six months. This first release of data is the culmination of 15 months worth of observations representing close to a trillion overall samples. Planck records on average of 10,000 samples every second and scans every point in the sky about 1,000 times.

That’s a challenge to analyze, even for a supercomputer. Hopper is a Cray XE6 supercomputer based at the Department of Energy’s National Energy Research Scientific Computing center (NERSC) at the Lawrence Berkeley National Laboratory in California. Named after computer scientist and pioneer Grace Hopper, the supercomputer has a whopping 217 terabytes of memory running across 153,216 computer cores with a peak performance of 1.28 petaflops a second. Hopper placed number five on a November 2010 list of the world’s top supercomputers. (The Tianhe-1A supercomputer at the National Supercomputing Center in Tianjin China was number one at a peak performance of 4.7 petaflops per second).

One of the main challenges for the team sifting through the flood of CMB data generated by Planck was to filter out the “noise” and bias from the detectors themselves.

“It’s like more than just bugs on a windshield that we want to remove to see the light, but a storm of bugs all around us in every direction,” said Planck project scientist Charles Lawrence. To overcome this, Hopper runs simulations of how the sky would appear to Planck under different conditions and compares these simulations against observations to tease out data.

“By scaling up to tens of thousands of processors, we’ve reduced the time it takes to run these calculations from an impossible 1,000 years to a few weeks,” said Berkeley lab and Planck scientist Ted Kisner.

But the Planck mission isn’t the only data that Hopper is involved with. Hopper and NERSC were also involved with last year’s discovery of the final neutrino mixing angle. Hopper is also currently involved with studying wave-plasma interactions, fusion plasmas and more. You can see the projects that NERSC computers are tasked with currently on their site along with CPU core hours used in real time. Maybe a future descendant of Hopper could give Deep Thought of Hitchhiker’s Guide to the Galaxy fame competition in solving the answer to Life, the Universe, and Everything.

Also, a big congrats to Planck and NERSC researchers. Yesterday was a great day to be a cosmologist. At very least, perhaps folks won’t continue to confuse the field with cosmetology… trust us, you don’t want a cosmologist styling your hair!

March 20, 2013April 26, 2016 by David Dickinson

U.S. To Restart Plutonium Production for Deep Space Exploration

A marshmellow-sized Pu-238 pellet awaits a space mission. (Credit: The Department of Energy).

The end of NASA’s plutonium shortage may be in sight. On Monday March 18^th, NASA’s planetary science division head Jim Green announced that production of Plutonium-238 (Pu-238) by the United States Department of Energy (DOE) is currently in the test phases leading up to a restart of full scale production.

“By the end of the calendar year, we’ll have a complete plan from the Department of Energy on how they’ll be able to satisfy our requirement of 1.5 to 2 kilograms a year.” Green said at the 44^th Lunar and Planetary Science Conference being held in Woodlands, Texas this past Monday.

This news comes none too soon. We’ve written previously on the impending Plutonium shortage and the consequences it has for future deep space exploration. Solar power is adequate in most cases when you explore the inner solar system, but when you venture out beyond the asteroid belt, you need nuclear power to do it.

Production of the isotope Pu-238 was a fortunate consequence of the Cold War. First produced by Glen Seaborg in 1940, the weapons grade isotope of plutonium (-239) is produced via bombarding neptunium (which itself is a decay product of uranium-238) with neutrons. Use the same target isotope of Neptunium-237 in a fast reactor, and Pu-238 is the result. Pu-238 produces 280x times the decay heat at 560 watts per kilogram versus weapons grade Pu-239 and is ideal as a compact source of energy for deep space exploration.

Since 1961, over 26 U.S. spacecraft have been launched carrying Multi-Mission Radioisotope Thermoelectric Generators (MMRTG, or formerly simply RTGs) as power sources and have explored every planet except Mercury. RTGs were used by the Apollo Lunar Surface Experiments Package (ALSEP) science payloads left on by the astronauts on the Moon, and Cassini, Mars Curiosity and New Horizons enroute to explore Pluto in July 2015 are all nuclear powered.

Plutonium powered RTGs are the only technology that we have currently in use that can carry out deep space exploration. NASA’s Juno spacecraft will be the first to reach Jupiter in 2016 without the use of a nuclear-powered RTG, but it will need to employ 3 enormous 2.7 x 8.9 metre solar panels to do it.

The plutonium power source inside the Mars Science Laboratory's MMRTG during assembly at the Idaho National Laboratory. (Credit: Department of Energy?National Laboratory image under a Creative Commons Generic Attribution 2.0 License). — The plutonium power source inside the Mars Science Laboratory’s MMRTG during assembly at the Idaho National Laboratory. (Credit: Department of Energy/Idaho National Laboratory image under a Creative Commons Generic Attribution 2.0 License).

The problem is, plutonium production in the U.S. ceased in 1988 with the end of the Cold War. How much Plutonium-238 NASA and the DOE has stockpiled is classified, but it has been speculated that it has at most enough for one more large Flag Ship class mission and perhaps a small Scout class mission. Plus, once weapons grade plutonium-239 is manufactured, there’s no re-processing it the desired Pu-238 isotope. The plutonium that currently powers Curiosity across the surface of Mars was bought from the Russians, and that source ended in 2010. New Horizons is equipped with a spare MMRTG that was built for Cassini, which was launched in 1999.

Technicians handle an RTG at the Payload Hazardous Servicing Facility at the Kennedy Space Center for the Cassini spacecraft. (Credit: NASA).

As an added bonus, plutonium powered missions often exceed expectations as well. For example, the Voyager 1 & 2 spacecraft had an original mission duration of five years and are now expected to continue well into their fifth decade of operation. Mars Curiosity doesn’t suffer from the issues of “dusty solar panels” that plagued Spirit and Opportunity and can operate through the long Martian winter. Incidentally, while the Spirit and Opportunity rovers were not nuclear powered, they did employ tiny pellets of plutonium oxide in their joints to stay warm, as well as radioactive curium to provide neutron sources in their spectrometers. It’s even quite possible that any alien intelligence stumbles upon the five spacecraft escaping our solar system (Pioneer 10 & 11, Voyagers 1 & 2, and New Horizons) could conceivably date their departure from Earth by measuring the decay of their plutonium power source. (Pu-238 has a half life of 87.7 years and eventually decays after transitioning through a long series of daughter isotopes into lead-206).

New Horizons in the Payload Hazardous Servicing Facility at the Kennedy Space Center. Note the RTG (black) protruding from the spacecraft. (Credit: NASA/Uwe W.)

The current production run of Pu-238 will be carried out at the Oak Ridge National Laboratory (ORNL) using its High Flux Isotope Reactor (HFIR). “Old” Pu-238 can also be revived by adding newly manufactured Pu-238 to it.

“For every 1 kilogram, we really revive two kilograms of the older plutonium by mixing it… it’s a critical part of our process to be able to utilize our existing supply at the energy density we want it,” Green told a recent Mars exploration planning committee.

Still, full target production of 1.5 kilograms per year may be some time off. For context, the Mars rover Curiosity utilizes 4.8 kilograms of Pu-238, and New Horizons contains 11 kilograms. No missions to the outer planets have left Earth since the launch of Curiosity in November 2011, and the next mission likely to sport an RTG is the proposed Mars 2020 rover. Ideas on the drawing board such as a Titan lake lander and a Jupiter Icy Moons mission would all be nuclear powered.

Engineers perform a fit check of the MMRTG on Curiousity at the Kennedy Space Center. The final installation of the MMRTG occured the evening prior to launch. (Credit: NASA/Cory Huston). — Engineers perform a fit check of the MMRTG on Curiosity at the Kennedy Space Center. The final installation of the MMRTG occurred the evening prior to launch. (Credit: NASA/Cory Huston).

Along with new plutonium production, NASA plans to have two new RTGs dubbed Advanced Stirling Radioisotope Generators (ASRGs) available by 2016. While more efficient, the ASRG may not always be the device of choice. For example, Curiosity uses its MMRTG waste heat to keep instruments warm via Freon circulation. Curiosity also had to vent waste heat produced by the 110-watt generator while cooped up in its aero shell enroute to Mars.

Cutaway diagram of the Advanced Stirling Radioisotope Generator. (Credit: DOE/NASA).

And of course, there are the added precautions that come with launching a nuclear payload. The President of the United States had to sign off on the launch of Curiosity from the Florida Space Coast. The launch of Cassini, New Horizons, and Curiosity all drew a scattering of protesters, as does anything nuclear related. Never mind that coal fired power plants produce radioactive polonium, radon and thorium as an undesired by-product daily.

An RTG (in the foreground on the pallet) left on the Moon by astronauts during Apollo 14. (Credit: NASA/Alan Shepard).

Said launches aren’t without hazards, albeit with risks that can be mitigated and managed. One of the most notorious space-related nuclear accidents occurred early in the U.S. space program with the loss of an RTG-equipped Transit-5BN-3 satellite off of the coast of Madagascar shortly after launch in 1964. And when Apollo 13 had to abort and return to Earth, the astronauts were directed to ditch the Aquarius Landing Module along with its nuclear-powered science experiments meant for the surface of the Moon in the Pacific Ocean near the island of Fiji. (They don’t tell you that in the movie) One wonders if it would be cost effective to “resurrect” this RTG from the ocean floor for a future space mission. On previous nuclear-equipped launches such as New Horizons, NASA placed the chance of a “launch accident that could release plutonium” at 350-to-1 against Even then, the shielded RTG is “over-engineered” to survive an explosion and impact with the water.

But the risks are worth the gain in terms of new solar system discoveries. In a brave new future of space exploration, the restart of plutonium production for peaceful purposes gives us hope. To paraphrase Carl Sagan, space travel is one of the best uses of nuclear fission that we can think of!

March 18, 2013December 23, 2015 by David Dickinson

Stalking the Lunar X

The Lunar X, captured by the author on June 8th, 2011.

This week offers observers a shot at capturing a fascinating but elusive lunar feature.

But why study the Moon? It’s a question we occasionally receive as a backyard astronomer. There’s a sort of “been there, done that” mentality associated with our nearest natural neighbor in space. Keeping one face perpetually turned Earthward, the Moon goes through its 29.5 synodic period of phases looking roughly the same from one lunation to the next. Then there’s the issue of light pollution. Many deep sky imagers “pack it in” during the weeks surrounding the Full Moon, carefully stacking and processing images of wispy nebulae and dreaming of darker times ahead…

But fans of the Moon know better. Just think of life without the Moon. No eclipses. No nearby object in space to give greats such as Sir Isaac Newton insight into celestial mechanics 101. In fact, there’s a fair amount of evidence to suggest that life arose here in part because of our large Moon. The Moon stabilizes our rotational axis and produces a large tidal force on our planet. And as all students of lunar astronomy know, not all lunations are exactly equal.

A daytime capture of the Lunar X. (Photo by Author).

This week, we get a unique look at a feature embedded in the lunar highlands which demonstrates this fact. The Lunar X, also sometimes known as the Purbach cross or the Werner X reaches a decent apparition on March 19^th at 11:40UT/7:40EDT favoring East Asia and Australia. This feature is actually the overlapping convergence of the rims of Blanchinus, La Caille and Purbach craters. The X-shaped feature reaches a favorable illumination about six hours before 1^st Quarter phase and six hours after Last Quarter phase. It is pure magic watching the X catch the first rays of sunlight while the floor of the craters are still immersed in darkness. For about the span of an hour, the silver-white X will appear to float just beyond the lunar terminator.

Visibility of the Lunar X for the Remainder of 2013.
Lunation	Date	Time	Phase	Favors
1116	March 19^th	11:40UT/7:40EDT	Waxing	East Asia/Australia
1116	April 3^rd	3:20UT/23:20EDT*	Waning	Africa/Europe
1117	April 17^th	23:47UT/19:47EDT	Waxing	Eastern North America
1117	May 2^nd	16:19UT/12:19EDT	Waning	Central Pacific
1118	May 17^th	10:51UT/6:51EDT	Waxing	East Asia/Australia
1118	June 1^st	4:31UT/0:31EDT	Waning	Western Africa
1119	June 15^th	21:21UT/17:21EDT	Waxing	South America
1119	June 30^th	16:04UT/12:04EDT	Waning	Western Pacific
1120	July 15^th	7:49UT/3:49EDT	Waxing	Australia
1120	July 30^th	3:16UT/23:16EDT*	Waning	Africa/Western Europe
1121	August 13^th	18:50UT/14:50EDT	Waxing	South Atlantic
1121	August 28^th	14:27UT/10:27EDT	Waning	Central Pacific
1122	September 12^th	9:50UT/5:50EDT	Waxing	East Asia/Australia
1122	September 27^th	2:00UT/22:00EDT*	Waning	Middle East/East Africa
1123	October 11^th	19:52UT/15:52EDT	Waxing	Atlantic Ocean
1123	October 26^th	14:12UT/10:12EDT	Waning	Central Pacific
1124	November 10^th	10:03UT/5:03EST	Waxing	East Asia/Australia
1124	November 25^th	3:14UT/22:14EST*	Waning	Africa/Europe
1125	December 10^th	00:57UT/19:57EST	Waxing	Western North America
1126	December 24^th	17:07UT/12:07EST	Waning	Western Pacific
Times marked in bold* denote visibility in EDT/EST the evening prior.

Fun Factoid: All lunar apogees and perigees are not created equal either. The Moon also reaches another notable point tonight at 11:13PM EDT/ 3:13 UT as it arrives at its closest apogee (think “nearest far point”) in its elliptical orbit for 2013 at 404,261 kilometres distant. Lunar apogee varies from 404,000 to 406,700 kilometres, and the angular diameter of the Moon appears 29.3’ near apogee versus 34.1’ near perigee. The farthest and visually smallest Full Moon of 2013 occurs on December 17^th.

The first sighting of the Lunar X feature remains a mystery, although modern descriptions of the curious feature date back to an observation made by Bill Busler in June 1974. As the Sun rises across the lunar highlands the feature loses contrast. By the time the Moon reaches Full, evidence of the Lunar X vanishes all together. With such a narrow window to catch the feature, many longitudes tend to miss out during successive lunations. Note that it is possible to catch the 1^st and Last Quarter Moon in the daytime.

A 1st Quarter Moon with the Lunar X (inset). (Photo by Author).

Compounding the dilemma is the fact that the lighting angle for each lunation isn’t precisely the same. This is primarily because of two rocking motions of the Moon known as libration and nutation. Due to these effects, we actually see 59% of the lunar surface. We had to wait for the advent of the Space Age and the flight of the Soviet spacecraft Luna 3 in 1959 to pass the Moon and look back and image its far side for the first time.

We actually managed to grab the Lunar X during a recent Virtual Star Party this past February. Note that another fine example of lunar pareidolia lies along the terminator roughly at the same time as the Lunar X approaches favorable illumination. The Lunar V sits near the center of the lunar disk near 1^st and Last Quarter as well and is visible right around the same time. Formed by the confluence of two distinct ridges situated between the Mare Vaporum and Sinus Medii, it is possible to image both the Lunar X and the Lunar V simultaneously!

A simultaneous capture of the Lunar X & the Lunar V features. (Photo by Author).

This also brings up the interesting possibility of more “Lunar letters” awaiting discovery by keen-eyed amateur observers… could a visual “Lunar alphabet be constructed similar to the one built by Galaxy Zoo using galactic structures? Obviously, the Moon has no shortage of “O’s,” but perhaps “R” and “Q” would be a bit more problematic. Let us know what you see!

-Thanks to Ed Kotapish for providing us with the calculations for the visibility of the Lunar X for 2013.

March 15, 2013April 26, 2016 by David Dickinson

Citizen Science, Old-School Style: The True Tale of Operation Moonwatch

An Operation Moonwatch team in action based out of Terre Haute, Indiana. (Courtesy of Keep Watching the Skies! Author Patrick McCray, used with Permission).

Amateur astronomers have done more than just watch the skies, they’ve been a national security asset. In the mid-1950’s, it was realized that the reality of the Space Age was at best only a decade away. Sub-orbital German V-2 rockets captured by the Soviets and the United States were reaching higher and higher altitudes, and it was only a matter of time before orbital velocity would be achieved.

Keep in mind, this was the age of backyard bomb shelters, “duck and cover” drills, and civil preparedness as Cold War fever reached a heightened pitch. Ground Observer Corps encouraged and trained citizen groups how to spot and report enemy bombers approaching the U.S coast in preparation for a nuclear confrontation. And remember, there was no reason to think that this build up wouldn’t extend to the militarization of space. It was in this era that Operation Moonwatch was born.

Conceived by Harvard astronomer Fred Whipple, Operation Moonwatch was the “Galaxy Zoo” of its day. The idea was simple; teams of observers around the world would track, time and record satellite passes over their location and feed this data back to the computation center at Cambridge, Massachusetts (telephone, Western Union or ham radio were the methods of the day) This data would give engineers information as to where to point their enormous Baker-Nunn cameras. These instruments were wide-field Schmidt cameras that could cover large swaths of the sky. They were to be positioned at 12 locations worldwide to keep tabs on satellites in low Earth orbit (LEO).

A Baker-Nunn satellite tracking camera ready for action. (Credit: NASA).

To be sure, there were obstacles to overcome. The Baker-Nunn cameras were well behind schedule, and the entire system was struggling to come online by mid-1958 in time for the International Geophysical Year (IGY). School and community groups had to be organized, trained, and equipped. Knowing precise location in the pre-GPS era had to be addressed. Many purchased optical kits available from Radio Shack, while many teams built their own. Then there was the dilemma of what a satellite would actually look like to an observer on the ground. Could a trained spotter even see it? Civil Air Patrol groups experimented with various trial substitutions, such as following aircraft, flocks of birds and bats at dusk and even tracking pebbles tossed into the sky!

Operation Moonwatch was also to play a part of the 1958 International Geophysical Year. Many doubted to effectiveness of amateur groups, but public interest ran high. Then on October 4th 1957, the world was caught off guard as Sputnik 1 lifted off from the Baikonur Cosmodrome.

The metal ball that started it all... Sputnik 1. (Credit: NASA/Asif A. Siddiqi). — The metal ball that started it all… Sputnik 1. (Credit: NASA/Asif A. Siddiqi).

The world was stunned that the Soviets had beaten the West into space. The National Advisory Committee for Aeronautics (later to become NASA in 1958) had yet to achieve a successful orbital launch, and the United States Naval Research Laboratory was still floundering to get the Vanguard program off the pad. The launch of Sputnik found a scant few Moonwatch teams at the ready to catch its first dusk passes over the United States. Keep in mind, the Sputnik satellite was too small and faint to see with the naked eye. What most casual observers in the general public saw (remember the opening scenes in the movie October Sky?) was actually the rocket booster that put Sputnik into space.

Moonwatch teams would “look up by looking down” using a bench mounted telescope that looked at a reflective plate aimed skyward. With observers arranged in a row aimed at a picket line, they would call out when the target satellite crossed the local meridian. This would in turn be documented by an onsite recorder for transmission.

A classic Operation Moonwatch bench instrument sold by Edmund Scientifc. (Credit: The Smithsonian Natinal Air & Space Museum). — A classic Operation Moonwatch bench instrument sold by Edmund Scientific (Credit: The Smithsonian National Air & Space Museum).

With Sputnik, the Operation Moonwatch volunteers found themselves thrust into the spotlight. Newspapers & radio shows clamored to interview volunteers, as the public suddenly became obsessed with space. Moonwatchers followed and documented to launch of the dog Laika aboard Sputnik 2 on November 3^rd, 1957, and when the U.S. finally launched its first satellite Explorer I on February 1^st 1958 Operation Moonwatch tracked it. Magazines such as National Geographic and Boys Life ran articles on the project and told teams how they could participate. When Sputnik 4 reentered over the U.S. on September 1962, it was data from Operation Moonwatch observers that proved vital in its recovery.

How Operation Moonwatch fit into the hierarchy. (Credit: NASA archives, The Role of the NAS & TPESP). — How Operation Moonwatch fit into the hierarchy. Note how amateur groups were associated with this press. (Credit: NASA archives, *The Role of the NAS & TPESP*).

Moonwatch was disbanded in 1975, but many volunteers continued tracking satellites and sharing data on their own. I always think that it’s fascinating that three very early satellites from the early days of Operation Moonwatch are still in orbit and can been seen with a good pair of binoculars and a little patience , Vanguards 1, 2 & 3. It could be argued that Operation Moonwatch provided a civilian means to monitor the goings on of governments in low Earth orbit and may have contributed to the Outer Space Treaty outlawing the use of nuclear weapons in space. Another fortunate occurrence of the era was the establishment of a civilian space agency in the U.S., argued for successfully by Dr. James Van Allen. How different would the course of history have been if the U.S. space program had become a “fourth branch” of the military?

Cincinnati plaque commemorating Operation Moonwatch. (Brian Van Flandern Public Domain image).

Today, modern satellite trackers still follow, image and share information on satellites worldwide. This effort transcends borders; when hazardous payloads such as Russia’s failed Mars mission Phobos-Grunt reentered in early 2012 satellite trackers documented its final passage, and efforts are still underway to keep tabs on the USAF’s X-37 spy satellite. One can also see a stark contrast between the efforts to enlist civilian effort during the Cold War and the modern Global War on Terrorism. Interest in science was at an all-time high in the 1950’s, as it was realized the West might be lagging behind in science education. In a post-9/11 era, there almost seems to be a movement to isolate participation. Many model rocketry groups are under increased restriction, and even amateur astronomers may see essential tools such as green laser pointers restricted for use.

Image of Space Shuttle Discovery on STS-119 captured from the ground… note the NASA “Blue Meatball” logo on the wing! (Credit: Ralf Vandebergh, used with permission).

But the good news is, anyone can still track a satellite from the comfort of their own backyard all in the spirit of Operation Moonwatch. DARPA announced a project last year which may resurrect a program similar to Operation Moonwatch. Named SpaceView, this program seeks to augment the U.S. Air Force’s Space Surveillance Network. Keep an eye on the sky, and remember a dedicated few amateur observers that played a crucial role in modern history as you watch satellites drift silently by in the twilight skies.

For more on the fscinating hostory of Operation Moonwatch, read Patrick McCray’s Keep Watching the Skies!

See more of Ralf Vandebergh’s outstanding work at his site Telescopic Spaceflight Images.

March 13, 2013April 26, 2016 by David Dickinson

WISE Nabs the Closest Brown Dwarfs Yet Discovered

WISE J104915.57-531906 from NASA's WISE survey (centered) and resolved to should its binary nature by the Gemini Observatory (inset). (Credit: NASA/JPL/Gemini Observatory/AURA/NSF).

We now know our stellar neighbors just a little better, and a new discovery may help tell us how common brown dwarfs are in our region of the galaxy. Early this week, researchers at Pennsylvania State University announced the discovery of a binary brown dwarf system. With a parallax measurement of just under 0.5”, this pair is only 6.5 light years distant making it the third closest system to our own and the closest example of the sub-stellar class of objects known as brown dwarfs yet discovered.

Named WISE J104915.57-531906, the system was identified by analysis of multi-epoch astrometry carried out by NASA’s Wide-field Infrared Survey Explorer (WISE). The discovery was made by associate professor of astronomy and astrophysics at Penn State’s Center for Exoplanets and Habitable Worlds Kevin Luhman. The system’s binary nature and follow up observations were confirmed by spectroscopic analysis carried out by the Gemini Observatory’s Multi-Object Spectrographs (GMOS).

Animation showing the motion of WISE 1049-5319 across the All-WISE, 2MASS & Sloan Digital Sky Survyies from 1978 to 2010. (Credit: NASA/STScI/JPL/IPAC/University of Massachusetts.) — Animation showing the motion of WISE 1049-5319 across the All-WISE, 2MASS & Sloan Digital Sky Surveys from 1978 to 2010. (Credit: NASA/STScI/JPL/IPAC/University of Massachusetts.)

This find is also the closest stellar system discovered to our own solar system since the discovery of Barnard’s star by astronomer E.E. Barnard in 1916. Incidentally, Barnard’s star was the center of many spurious and controversial claims of extrasolar planet discoveries in the mid-20^th century. Barnard’s star is 6 light years distant, and the closest star system to our own is Alpha Centauri measured to be 4.4 light years distant in 1839. In 1915, the Alpha Centauri system was determined to have a faint companion now known as Proxima Centauri at 4.2 light years distant. The Alpha Centauri system also made headlines last year with the discovery of the closest known exoplanet to Earth. WISE 1506+7027 is the closest brown dwarf to our solar system yet discovered. This also breaks the extended the All-WISE survey’s own previous record of the closest brown dwarf released in 2011, WISE 1506+7027 at 11.1 light years distant.

When looking for nearby stellar suspects, astronomers search for stars displaying a high proper motion across the sky. The very first parallax measurement of 11 light years distant was obtained by Friedrich Bessel for the star 61 Cygni in 1838. 61 Cygni was known as “Piazzi’s Flying Star” for its high 4.2” proper motion across the sky. To giving you an idea of just how tiny an arc second is, a Full Moon is about 1800” in diameter. With a proper motion of just under 3” per year, it would take WISE 1049-5319 over 600 years to cross the same apparent distance in the sky as viewed from the Earth!

An artist's conception of looking back at Sol from the binary brown dwarf system WISE 1049-5319, 6.5 light years distant. (Credit: Janella Williams, Penn State University). — An artist’s conception of looking back at Sol from the binary brown dwarf system WISE 1049-5319, 6.5 light years distant. (Credit: Janella Williams, Penn State University).

“Based on how this star system was moving in images from the WISE survey, I was able to extrapolate back in time to predict where it should have been located in older surveys,” stated Luhman. And sure enough, the brown dwarf was there in the Deep Near-Infrared Survey of the Southern Sky (DENIS), the Two Micron All-Sky Survey (2MASS) and the Sloan Digitized Sky Survey (SDSS) spanning a period from 1978 to 1999. Interestingly, Luhman also points out in the original paper that the pair’s close proximity to the star rich region of galactic plane in the constellation Vela deep in the southern hemisphere sky is most likely the reason why they were missed in previous surveys.

The discovery of the binary nature of the pair was also “an unexpected bonus,” Luhman said. “The sharp images from Gemini also revealed that the object actually was not just one, but a pair of brown dwarfs orbiting each other.” This find of a second brown dwarf companion will go a long way towards pinning down the mass of the objects. With an apparent separation of 1.5”, the physical separation of the pair is 3 astronomical units (1 AU= the Earth-Sun distance) in a 25 year orbit.

Size comparison of stellar vs substellar objects. (Credit: NASA/JPL-Caltech/UCB).

Brown dwarfs are sub-stellar objects with masses too low (below ~75 Jupiter masses) to sustain the traditional fusion of hydrogen into helium via the full proton-proton chain process. Instead, objects over 13 Jupiter masses begin the first portion of the process by generating heat via deuterium fusion. Brown dwarfs are thus only visible in the infrared, and run a spectral class of M (hottest), L, T, and Y (coolest). Interestingly, WISE 1049-5319 is suspected to be on the transition line between an L and T-class brown dwarf. To date, over 600 L-type brown dwarfs have been identified, primarily by the aforementioned SDSS, 2MASS & DENIS infrared surveys.

General location of WISE 1049-5319 in the constellation Vela. Note its proximity to the galactic plane. (Created by the author using Starry Night).

This discovery and others like it may go a long ways towards telling us how common brown dwarfs are in our region of the galaxy. Faint and hard to detect, we’re just now getting a sampling thanks to surveys such as WISE and 2MASS. The James Webb Space Telescope will do work in the infrared as well, possibly extending these results. Interestingly, Luhman notes in an interview with Universe Today that the potential still exists for the discovery of a brown dwarf closer to our solar system than Alpha Centauri. “No published study of the data from WISE or any other survey has ruled out this possibility… WISE is much more capable of doing this than any previous survey, but the necessary analysis would be fairly complex and time consuming. It’s easier to find something than to rule out its existence.” Said Luhman. Note that we’re talking a nearby brown dwarf that isn’t gravitationally bound to the Sun… this discussion is separate from such hypothetical solar companions as Nemesis and Tyche…and Nibiru conspiracy theorists need not apply!

The WISE 1049-5319 system is also a prime target in the search for nearby extra-solar planets. “Because brown dwarfs have very low masses, they exhibit larger reflex motions due to orbiting planets than more massive stars, and those larger reflex motions will be easier to detect.” Luhman told Universe Today. Said radial surveys for exoplanets would also be carried out in the IR band, and brown dwarfs also have the added bonus of not swamping out unseen planetary companions in the visible spectrum.

Congrats to Mr. Luhman and the Center for Exoplanets and Habitable Worlds on the discovery. You just never know what’s lying around in your own stellar backyard!

Read this original discovery paper here.

March 11, 2013April 26, 2016 by David Dickinson

Update: Comet PANSTARRS Makes Its Northern Hemisphere Debut

Comet PANSTARRS as seen from Arizona on March 10, 2013. Credit and copyright: Chris Schur.

The first of three bright comets anticipated in 2013 became visible to North American observers this past weekend. Comet C/2011 L4 PanSTARRS is now currently visible low to the southwest at dusk, if you know exactly where to look for it.

Observers in the southern hemisphere have been enjoying this comet for the past few weeks as it reached naked eye visibility above 6^th magnitude around late February and began its long trek northward. Comet PanSTARRS is on a 106,000+ year orbit with a high inclination of 84.2° with respect to the ecliptic. This also means that PanSTARRS is currently moving roughly parallel to the “0 Hour” line in Right Ascension (The same point occupied by the Sun during next week’s Vernal Equinox on March 20^th) and is only slowly gaining elevation on successive evenings.

CometPANSTARRS from Michael Zeiler on Vimeo.

Observers in Hawaii and Mexico picked up PanSTARRS late last week, and scattered reports of sightings from the southern continental United States started trickling in Saturday night on the evening of March 9^th. We managed to grab Comet PanSTARRS low to the southwest on Sunday evening on March 10^th, about 30 minutes after local sunset.

Comet PanSTARRS seen from Hudson Florida on the evening of March 10th (Photo by Author).

We were surprised by the star-like appearance of the coma, about +1^stto 2^nd magnitude with a tiny fan-shaped tail. The comet was visible in binoculars only (I used our trusty pair of Canon 15×45 Image-Stabilized binocs for the task) and I couldn’t yet pick out the comet with the naked eye.

Several sightings westward followed. Clay Davis based in Santa Fe, New Mexico noted a visual magnitude of -0.5, saying that PanSTARRS was “Brighter than Mars” at magnitude +1 but “A challenge to keep in view.” Note that observer estimations of the brightness of comets can vary based on local sky conditions. Also, unlike a pinpoint star, the brightness of comets extends over its visible surface area, much like a faint nebula. The first sightings of the comet for many observers has been contingent on the weather, which can trend towards overcast for much of North America in early March. From our +28.5° northern latitude vantage point here just north of Tampa Bay Florida we had about a 10 minute window from when the sky was dark enough to spy PanSTARRS before it set below the local horizon.

Here are a few more images from Universe Today readers:

Comet Pan-STARRS as imaged by Robert Sparks (@HalfAstro) on the night of March 10th from Tucson, Arizona. All Rights Reserved, part of the Universe Today photo gallery. — Comet PanSTARRS as imaged by Robert Sparks (@HalfAstro) on the night of March 10th from Tucson, Arizona. All Rights Reserved, part of the Universe Today photo gallery.

First views of Comet PANSSTARRS from Tucson, Arizona. Credit and copyright: Adam Block/Mount Lemmon SkyCenter.

Comet PANSTARRS from Puerto Rico on March 10, 2013. Credit and copyright: Efrain Morales.

To see the comet we suggest;

A clear uncluttered southwestern horizon;
A reasonably clear sky;
Binoculars.

First naked eye sightings of the comet for U.S. and European latitudes should be forthcoming over the next few evenings. PanSTARRS just passed perihelion yesterday on March 10^th at 0.3 Astronomical Units from the Sun (or 46.5 million kilometres, just inside the orbit of Mercury).

Comet PanSTARRS looking west at 8PM EDT from latitude 30 degrees north. (Created by the author using Starry Night). — Comet PanSTARRS looking west at 8PM EDT the evening of March 12th from latitude 30 degrees north. (Created by the author using Starry Night).

And Comet PanSTARRS may put on its best show over the next few nights. The Moon reaches New phase today at 3:51PM EDT/ 19:51 UT and starts lunation number 1116. On the next few evenings, the slim crescent Moon will slide by Comet PanSTARRS. Look for the 2% illuminated Moon 5° to the lower right of the comet on the evening of Tuesday March 12^th. On the next evening, the 5% illuminated Moon will be 9° above Comet PanSTARRS on Wednesday, March 13^th. The age of the Moon will be 28 hours old on Tuesday evening and 52 hours on Wednesday the 13^th respectively, an easy catch. The Moonwatch website is a great place to check for those early lunar crescent sighting possibilities worldwide. Note that Comet PanSTARRS also passes less than 30’ from the planet Uranus (about the diameter of the Full Moon) on the evening of the 12^th at 8 PM EDT/24UT. +6^th magnitude Uranus may just be visible near the head of the comet using binoculars or a small telescope. Keep in mind, they just appear to be close as seen from our Earthly vantage point. PanSTARRS is currently 1.1 A.U.s from the Earth, while Uranus is on the other side of the solar system at 21 A.U.s distant!

Comet PanSTARRS looking west at 8PM EDT from latitude 30 degrees north on the evening of March 13th. (Created by the author using Starry Night).

PanSTARRS also crosses the Celestial Equator today on March 11^th and the Ecliptic on March 13^th. Observers from dark sky sites may get the added bonus of the zodiacal light, a true photographic opportunity!

Spacecraft studying the Sun are also giving us views of Comet PanSTARRS from a different perspective. NASA’s twin STEREO A & B spacecraft are positioned to monitor the Sun from different vantage points along the Earth’s orbit. Often, they see comets as an added bonus. Comet PanSTARRS has just moved into the field of view of STEREO-B’s Heliospheric Imager and has given us amazing views of the comet and the Earth in the distance over the past week.

The view of Comet PanSTARRS from NASA's STEREO Behind observatory. (Credit: NASA/SECCHI). — The view of Comet PanSTARRS from NASA’s STEREO Behind observatory. (Credit: NASA/SECCHI).

From STEREO, the remarkable fan-shaped dust tail of PanSTARRS stands out in profile. The dust tail of a comet always points away from the Sun. Driven by the solar wind, a comet’s tail is actually in front of it as it heads back out of the solar system! An ultimate animation of Comet PanSTARRS just came to our attention today via @SungrazerComets on Twitter;

Animation of comet 2011 L4 PanSTARRS entering STEREO-B's HI camera, note the twin ion/dust tail reminiscent of Hale-Bopp! (Credit: NASA/STEREO/NRL). — Animation of comet 2011 L4 PanSTARRS entering STEREO-B’s HI camera, note the twin ion/dust tail reminiscent of Hale-Bopp! (Credit: NASA/STEREO/NRL).

As of this writing, PanSTARRS seems to be performing as per predictions with an observed magnitude of around +1. The comet will continue on its northward trek, becoming a circumpolar object for observers based around latitude 50° north on April 2nd. Comet PanSTARRS should dip back below +6^th magnitude around April 15th.

Comet PanSTARRS as imaged by Mike Weasner from Cassiopeia Observatory in southern Arizona on the night of March 10th. Used with permission.

But this is but Act One in a forecasted three act cometary saga for 2013. Comet C/2012 F6 Lemmon will grace early dawn skies in April for northern hemisphere observers, and then all eyes will be on Comet C/2012 S1 ISON for the hoped for grand finale later this year. Interestingly, ESA’s Solar Heliospheric Observatory will get a look at this sungrazing comet as it passes through its LASCO C3 camera’s field of view. Clear skies, and may 2013 go down as the Year of the Comet!

-Check out photos of Comet PanSTARRS and more being added daily to the Universe Today’s Flickr gallery.