June 1, 2020

Pluto at Opposition 2018: Transit Dreaming

Earth and the Moon in transit as seen from Pluto.

Credit: Starry Night.

What sorts of celestial scenes would you witness, if you could magically sit on some far flung space rock? An interesting upcoming alignment was recently brought to our attention by our friends over at Earth & Sky and astronomer Anne Verbiscer at the Department of Astronomy at the University of Virginia on the NASA New Horizons blog, prompting us to take a closer look at a unique event that will go unwitnessed by human (or robotic) eyes: a transit of the Earth and the Moon on July 12th, 2018 (as reckoned in Universal Time)… as seen from Pluto.

This alignment occurs because the 2018 opposition of Pluto sees it very near one of its two ecliptic crossing nodes. Orbiting the Sun once every 248 years in a highly inclined orbit tilted 17 degrees with respect to the Earth’s path, these crossings occur during alternate spans of 87 versus 161 years. In fact, it was during the last node crossing back in 1930 when Clyde Tombaugh spotted Pluto, drifting through the star fields of the astronomical constellation of Gemini the Twins. It’s sobering to think that in just over eight decades since its discovery, slow-moving Pluto has only moved seven constellations (we’re count the pesky non-zodiacal constellation Ophiuchus) eastward to Sagittarius the Archer in 2018.

The orbital nodes of Pluto. Graphic credit: Anne Verbiscer.

Incidentally, the fact that Pluto was near a node and the ecliptic plane–right where you’d expect a planet to hide—very probably upped Mr. Tombaugh’s chance’s of spotting it. Pluto was also moving towards perihelion 29.7 astronomical units (AU) from the Sun on September 5th, 1989, meaning it reached its maximum brightness of magnitude +13.7 during oppositions right around that year. In 2018, it’ll only reach magnitude +14.2 at opposition, as it heads toward aphelion 49.3 AU from the Sun in February, 2114.

What would you see on Pluto on July 12th of this year, staring back at the Sun? We’ll assume you’re equipped with a life support system to brave the brisk Plutonian realm of high noon, and a solar filtered telescope tuned for the dim, -19 magnitude Sun, brighter than a Full Moon but about 1/30,000th the brightness of high noon on Earth. Old Sol would only appear an arc minute across, barely showing a discernible disk to the naked eye. See that tiny 0.5” dot? That’s the Earth, taking about 10 hours to span the disk of the Sun. The Moon is tinier still, at a diminutive 0.2” arcseconds across as it accompanies the Earth on its trek. (better pack a really powerful telescope).

Pluto’s large moon Charon would be the top draw in the Plutonian sky, at only 11,800 miles distant and appearing an amazing four degrees across (that’s eight times larger than a Full Moon here on Earth!) as it went through its cycle of phases once every 6.4 days. Giant Charon can eclipse the tiny Sun on as seen from Pluto as well, which will next occur starting in 2107 AD. From Earth, we’ll see a series of mutual occultations of the pair around the same time, as Pluto and Charon alternate passing one in front of the other.

An amazing view: Pluto backlit by the Sun as seen from New Horizons in 2015 shortly after flyby. Credit: NASA/New Horizons.

What about NASA’s New Horizons spacecraft, just 4.5 degrees from Pluto as seen from the Earth? Unfortunately, that angle is juuust far enough off that Earth will miss transiting the Sun from its point of view. And even if it were, New Horizons Long Range Reconnaissance Imager (LORRI) imager—were it equipped to stare at the Sun—is equivalent to an 8” Schmidt-Cassegrain amateur telescope, a decent size, to be sure, but it would still have a tough time resolving a 0.5 arcsecond disk crossing the face of the Sun.

New Horizons will visit Kuiper Belt Object Ultima Thule coming right up on New Year’s Day, 2019.

After 2018, Pluto spends the next 161 years in the southern celestial hemisphere.  Mark your calendars: Stick around until–you guessed it January 12th, 2178 and again on January 13th, 2179 AD, and any would-be Plutonian colonists can at least witness a transit of Earth and the Moon across the Sun… for real.

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...]

Review: How I Killed Pluto & Why it Had it Coming by Mike Brown.

Target: Pluto?

Caltech Astronomer Mike Brown is on the cutting edge of modern day “faint fuzzy” hunting at the fringe of the solar system and has found himself at the epicenter of several scientific battles over the past decade. In How I Killed Pluto & Why it Had it Coming, Dr. Brown takes us behind the scenes of his discoveries and, after a brief history of solar system exploration, takes us on a deeply personal tale of modern discovery and a fascinating look at how modern astronomy in the Internet era gets done. Intertwined with the tale of successive discoveries in the outer solar system is an intimate look at Mike’s personal world, his family, and how a scientist and his family operates… just think, how many of us personally know a true scientist, in our families or on the block? [Read more...]

26.04.11: New Horizons and the Hunt for KBO’s.

A sky survey has begun this month for a very special mission. In July 2015, NASA’s New Horizons mission will whiz past the Pluto-Charon system on its way out of the solar system. Scientists will collect data on the pair for a frenzied few days…and then what?

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23.04.11: A Plutonian Atmosphere.

As the New Horizons spacecraft approaches the distant world, Pluto is beginning to seem more planet-like by the day. Recently a team including astrobiologist Jane Graves used time on telescopes perched atop Hawaii’s Mauna Kea complex to reveal an intriguing constituent of the Plutonian atmosphere; carbon monoxide.

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AstroEvent(s): A Week of Moons, Tri-Conjunctions, & Lunar Features!

This week offers a grab bag of unique events, far from the humdrum wide conjunctions and difficult to see pairings. The action starts on February 8th with a rare chance to see Saturn’s moons in 1 -8 order. This occurs in a narrow window from 19:01-19:38 UT, and thus favors the Asian Far East. The planet currently rises around 11PM local, and a majority of the moons should still be in order from your corresponding latitude.

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The Discovery of Eris & its Implications

As 2010 draws to a close, a quiet discovery was made recently about a fascinating solar system object. January 5th, 2011 will mark the six year anniversary of the discovery of 2003 UB313, which became provisionally known as the planet Xena and then later demoted to the dwarf planet Eris.

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16.05.10- Gliese 710: A Future Stellar Threat?

Our quiet corner of the local galaxy may be in for a future interloper. A possible solar system side-swipe comes in the form of Gliese 710, an unassuming +10 magnitude orange dwarf star currently 63 light years distant in the constellation Serpens. As we swirl around the center of our galaxy, stellar neighbors come and go like in-laws during your favorite respective obligatory familial holiday season. The low proper motion of this star hid its true nature until about a decade ago; generally, the lower the apparent motion, the more distant the star. Gliese 710, however, fits into a different class; a star that shows a low apparent motion because it’s moving towards us. Closest approach has been calculated by astronomer Joan Garcia-Sanchez of JPL as about 1.3 light years in 1.5 million years time. Doesn’t sound like much? Well, this skirts the edge of our Oort Cloud, that vast reservoir of comets that extends out to about 1.6 light years distant…Gliese 710 stands an 86% chance of breaking this threshold. In addition, a 2007 review of Hipparcos data by Vadim V. Bobylev shows that this star may pass as close as 0.02 of a light year, about 50 times farther than the (sometimes) planet Pluto. This could make things really interesting, as Gliese 710 could really stir things up in our Oort cloud. And of course, there is the question of whether or not Gliese 710 has an Oort Cloud of its own. More than likely, this pulse of comets will last for about a several million year span of time. Could our inner solar system have sustained such shocks before? One only has to look at the crater-scarred surface of our Moon to realize the inner solar system has served as a shooting gallery over the eons. The statistical probability of a really (i.e. 1,000 AU) approach is about 1 in 10,000, so don’t max out those credit cards just yet… this uncertainly stems from incomplete knowledge of all the gravitational factors at work. As more sensitive astrometrical platforms, such as ESA’s Gaia spacecraft come online, the nature of the threat from Gliese 710 will be more precisely known. At its closest approach, this inbound star will be about as bright as the red giant star Antares… here’s to the neighbors!

29.04.10-Name a Minor Planet!

Break out those mythological encyclopedias; the Committee for Small Body Nomenclature and the International Astronomical Union wants YOU, the school age public, to name a minor planet. Tomorrow, April 30th will have been one year since the passing of Venetia Burney Phair. At age 11, Miss Burney had the opportunity to suggest a name for the ever-controversial planet Pluto. Fans of this site will remember that she was also the subject of the outstanding documentary film Naming Pluto by director Ginita Jimenez.  Saturday, May 1st will also be the 80th Anniversary of the official adoption of the name Pluto.  Tomorrow, Friday April 30th 2010, a competition entitled Naming X will open to give school children the chance to duplicate Venetia Burney’s feat. Recognition will be first come, first credited, so don’t delay! Also, keep in mind that this is about the children; no bloggers (as jealous as we are!) can crash this party. Categories are detailed on the site for groups and individuals from elementary school age on up, with prizes that would make any astronomy fan blush. The judging panel includes notables such as Astroguyz former next door neighbor David Levy (I heard he’s discovered a comet or two), Professor Ian Morison, and Dr. Marc Buie. Now would be a perfect chance to get the kids excited about Kuiper Belt and Trans-Neptunian Objects, and maybe the whole celestial object naming business.

…And kids, don’t forget to take a few pointers from Venetia and how she accomplished her proposal; the name Pluto was selected from Roman mythology and fit well with the tradition of naming solar system objects. Resist the urge to submit the names of pets, favorite cartoon characters, and the like. And don’t forget, you have a tool that at your cyber-disposal that young Venetia didn’t have, the Internet. Not only will this allow you to scour the respective mythological pantheons, but will also give you the ability to check possible names for originality in astronomical use. Just think, Astroguyz has given you the edge already…beyond that, the rest is up to you. Astroguyz will be following to see what original ideas you come up with. Further instructions are on the site. Names are not to be longer than 16 characters, easily pronounceable, and to be accompanied by a brief justification of not more than 25 words. May the best student and/or group win!

18.04.10- Zeroing in on Nearby Exoplanets.

It’s hard to believe that a little less than two decades ago, no extra-solar planets were known. Now, the count climbs daily, and platforms like the Kepler Space Telescope threaten to launch the tally into the thousands. Recently, an international team of astronomers made six new discoveries in two nearby star systems that may eventually lead towards the cosmic Holy Grail; an exoplanet resembling Earth. The team was led by prolific planet hunter Paul Butler and Steve Vogt, who discovered the super-Earths by combining radial velocity data gathered from the Anglo-Australian telescope and the Keck observatory. First up is 61 Virginis, a Sun-like star 28 light years away. This system has always been of interest to astronomers because it is a near twin to our own Sun and is on the short list for NASA’s Terrestrial Planet Finder. The team discovered three worlds ranging in mass from 5 Earths to 25. In addition, follow-up studies with the Spitzer Space telescope find evidence for a dust ring around 61 Virginis about twice Pluto’s distance from our own Sun. The second discovery is one 7.5 Earth mass planet and a possible two more found around the star HD 1461 in the constellation Cetus about 76 light years distant. Again, HD 1461 could pass for our Sun in terms of age, size, and mass. Both stars would be visible to the naked eye under reasonably dark skies. It remains to be seen if these worlds are rocky terrestrial planets or Uranus-like slush balls. Evidence is mounting, however, that planets may be common around nearby Sun-like stars. The innermost planetary detection for 61 Virginis also represents the smallest amplitude discovery ever made by astronomers. These discoveries were backed up by brightness measurements made by robotic telescopes based in Arizona and operated by Tennessee University’s George Henry. This ruled out the possibility that the amplitude variations seen were due to variability or “starspots”. The Lick-Carnegie Exoplanet Survey Team will also soon have a new weapon in its arsenal; the recently completed Automated Planet Finder (APF) Telescope atop Mount Hamilton. All that’s needed now is for the Discovery Channel to fund a new hit series; The Exoplanet Hunters!

Review: Gardens of the Sun by Paul McAuley.

It was with great anticipation and excitement that we finally got to dig into our advanced reading copy of Gardens of the Sun by Paul McAuley, out March 23, 2010 courtesy of Pyr BooksGardens picks up where last years’ first opus, The Quiet War, left off, and fans of the series will not be disappointed. The near-future battle for the ultimate direction of humanity spans the solar system as the Three Powers Alliance of Earth struggles to consolidate its hold on the Jovian and Saturnian systems, while the decimated Outers flee into the depths of the exterior solar system. [Read more...]

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…

Astro-Challenge: Groombridge 34; a Nearby Red Dwarf Pair!

Sure, everyone’s heard of Alpha Centauri, but have you ever heard of… Groombridge 34? We came across this little known binary red dwarf pair while perusing Burnham’s Celestial Handbook last month during our write up for M31. Also in the constellation Andromeda, Groombridge 34 is a unique system; a pair of red dwarf flare stars relatively close to our own solar system. At 11.62 light years, its the 16th closest stellar system to our own. The separation of the two stars are about 147 Astronomical units (A. U.s) (for reference, Pluto is about 50 A.U.s from the sun!) in a estimated 2,600 year orbit.

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Review:Redshift 7: The Ultimate in Astronomy Software.

Desktop-based planetarium programs have really come into their own in the past few years. From their early evolution in the 1980′s with computer programs written in Basic that would show you stick figure constellations, planetarium programs are now full fledged sky simulators that allow you not only to control your telescope and plan your observing sessions more effectively, but allow you to travel through space as well as time.

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Searching for Robert Burnham.

Sometimes, the quietest minds among us also have the most to share with the world.

Last month, on a warm summer’s day in August, the East Valley Astronomy Club, in connection with the Robert Burnham Jr. Memorial Fund, honored a man with the dedication of a small plaque placed on the Pluto walk at the Lowell Observatory. That man is probably the most unknown, but influential amateur astronomer of the 20th century; Robert Burnham Jr. a man that but for a singular colossal work, might have passed on into total obscurity. The book is Burnham’s Celestial Handbook, a three volume guide to the wonders of the night sky. [Read more...]

31.08.09: An Edge on Saturn.

A rather odd event is transpiring in the Saturnian system, one that only happens a couple of times in our lifetime; its rings are vanishing. Not really, of course; we are merely passing through the super-fine ring plane as viewed from the Earth. The exact date of the “crossing” as viewed from Earth is Friday, September 4th, when the 20 meter thick rings will be exactly edge on and vanish from all but the largest telescopes. Just a few weeks ago, Saturn passed equinox, when the rings were edge on to the Sun and hence, not illuminated across their 100,000+ km expanse. This happens every 14 to 15 years during the planet’s 29.7 year orbit.

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Review: Naming Pluto.

We here at Astroguyz are always on the lookout for an unheard of astronomical tale. Naming Pluto, a short documentary film by Ginita Jimenez of Father Films tells the intriguing story of how the ever-controversial planet Pluto was first named. It is a very human drama, and one that should be better known than it is.

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April 2009 News & Notes.

The Successful Launch of Kepler: The Kepler space telescope launched successfully last month on March 6th, during a spectacular night launch. Sporting one of the biggest CCD imagers ever to leave Earth, Kepler is bound for an Earth-trailing, heliospheric orbit. Kepler will spend several months staring at a patch of sky in the direction of Cygnus looking for one of the holy grails in astronomy; Earth-sized, terrestrial planets. Stay tuned! This could be one of the potential discoveries of the year!

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