Spin! Crab Pulsar Speed Jumps Linked To Billions Of Tiny Vortices

Artist's conception of a gamma-ray pulsar. Gamma rays are shown in purple, and radio radiation in green. Credit: NASA/Fermi/Cruz de Wilde

Pulsars — those supernova leftovers that are incredibly dense and spin very fast — may change their speed due to activity of billions of vortices in the fluid beneath their surface, a new study says.

The work is based on a combination of research and modelling and looks at the Crab Nebula pulsar, which has periodic slowdowns in its rotation of at least 0.055 nanoseconds. Occasionally, the Crab and other pulsars see their spins speed up in an event called a “glitch”. Luckily for astronomers, there is a wealth of data on Crab because the Jodrell Bank Observatory in the United Kingdom looked at it almost daily for the last 29 years.

A glitch, the astronomers said in a statement, is “caused by the unpinning and displacement of vortices that connect the [pulsar’s] crust with the mixture of particles containing superfluid neutrons beneath the crust.”

“Surprisingly, no one tried to determine a lower limit to glitch size before. Many assumed that the smallest glitch would be caused by a single vortex unpinning. The smallest glitch is clearly much larger than we expected,” stated Danai Antonopoulou from the University of Amsterdam.

The astronomers added they will need more observations of other pulsars to better understand the results.

You can read the paper at the Monthly Notices of the Royal Astronomical Society or in preprint version on Arxiv. The research was led by C.M. Espinoza of the University of Manchester and Chile’s Pontifical Catholic University.

Source: NOVA

Supernova Sweeps Away Rubbish In New Composite Image

The supernova remnant G352.7-0.1 in a composite image with X-rays from the Chandra X-Ray Telescope (blue), radio waves from the Very Large Array (pink), infrared information from the Spitzer Space Telescope (orange) and optical data from the Digital Sky Survey (white). Credit: X-ray: NASA/CXC/Morehead State Univ/T.Pannuti et al.; Optical: DSS; Infrared: NASA/JPL-Caltech; Radio: NRAO/VLA/Argentinian Institute of Radioastronomy/G.Dubner

Shining 24,000 light-years from Earth is an expanding leftover of a supernova that is doing a great cleanup job in its neighborhood. As this new composite image from NASA reveals, G352.7-0.1 (G352 for short) is more efficient than expected, picking up debris equivalent to about 45 times the mass of the Sun.

“A recent study suggests that, surprisingly, the X-ray emission in G352 is dominated by the hotter (about 30 million degrees Celsius) debris from the explosion, rather than cooler (about 2 million degrees) emission from surrounding material that has been swept up by the expanding shock wave,” the Chandra X-Ray Observatory’s website stated.

“This is curious because astronomers estimate that G352 exploded about 2,200 years ago, and supernova remnants of this age usually produce X-rays that are dominated by swept-up material. Scientists are still trying to come up with an explanation for this behavior.”

More information about G352 is available in the Astrophysical Journal and also in preprint version on Arxiv.

Source: Chandra X-Ray Telescope

Two Observing Challenges: Catch Venus Passing Neptune And Occulting a Bright Star

The Milky Way, The Large and Small Magellanic Clouds, Zodiacal Light, and Venus as seen from the Karoo Desert in South Africa early this month. Credit: Cory Schmitz.

 Have you been following the planet Venus this season? 2014 sees the brightest planet in our Earthly skies spend a majority of its time in the dawn. Shining at magnitude -3.8, it’s hard to miss in the morning twilight. But dazzling Venus is visiting two unique celestial objects over the next week, and both present unique observing challenges for the seasoned observer.

First up is an interesting close conjunction of the planets Venus and Neptune on the morning of Saturday, April 12th. Closest conjunction occurs at 3:00 Universal Time (UT) April 12th favoring Eastern Europe, the Middle East and eastern Africa, when the two worlds appear to be just 40 arc minutes apart, a little over – by about 10’ – the apparent size of a full Moon. Shining at magnitude +7.8 and 30,000 times fainter than Venus, you’ll need a telescope to tease out Neptune from the pre-dawn sky. Both objects will, however, easily fit in a one degree field of view, in addition to a scattering of other stars.

Stellarium
Looking to the east the morning of April 12th from the U.S. East Coast near latitude 30 degrees north.  Nearby stars are annotated in red by magnitude with decimals omitted. Created using Stellarium, click to enlarge.

At low power, Venus will display a 59% illuminated gibbous phase 20” across on the morning of the 12th, while Neptune will show a tiny disk barely 2” across. Still, this represents the first chance for viewers to recover Neptune since solar conjunction behind the Sun on February 23rd, 2014, using dazzling Venus as a guide.

Both sit 45 degrees west of the Sun and currently rise around 3 to 4 AM local dependent on latitude.

This is one of the closest planet-planet conjunctions for 2014. The closest is Venus and Jupiter at just 0.2 degrees apart on August 18th. This will represent the brightest planet versus planet conjunction for the year, and is sure to illicit multiple “what’s those two bright stars in the sky?” queries from morning commuters… hopefully, such sightings won’t result in any border skirmishes worldwide.

Now, for the mandatory Wow factor. On the date of conjunction, Earth-sized Venus is 0.84 Astronomical Units (A.U.s) or over 130 million kilometres distant. Ice giant Neptune, however, is 30.7 AUs or 36 times as distant, and only appears tiny though it’s almost four times larger in diameter.  Sunlight reflected from Venus takes 7 minutes to reach Earth, but over four hours to arrive from Neptune. We’ve visited Venus lots, and the Russians have even landed there and returned images from its smoldering surface, but we’ve only visited Neptune once, during a brief flyby of Voyager 2 in 1989.

From Neptune looking back on April 12th, Earth and Venus would appear less than 1 arc minute apart…. though they’d also be just over one degree from the Sun!

The "shadow path" of the occultation of Lambda Aquarii by Venus on April 16th. Credit: IOTA/Steve Preston/www.asteroidoccultation/Occult 4.0.
The “shadow path” of the occultation of Lambda Aquarii by Venus on April 16th. Credit: IOTA/Steve Preston/www.asteroidoccultation/Occult 4.0.

But an even more bizarre event happens a few days later on April 16th, though only a small region of the world in the South Pacific may bare witness to it.

Next Wednesday from 17:59 to 18:13 UT Venus occults the +3.7 magnitude star HIP 112961 also known as Lambda Aquarii on the morning of April 16th 2014.

Venus will be a 61% illuminated gibbous phase 19” in diameter. Unfortunately, although North America is rotated towards the event, it’s also in the middle of the day.

The best prospects to observe the occultation are from New Zealand and western Pacific at dawn. The star will disappear behind the bright limb of Venus in dawn twilight before emerging on its dark limb 5 minutes later as seen from New Zealand.

Starry Night
The path of Lambda Aquarii behind Venus as seen from New Zealand the morning of the 16th. Created in Starry Night.

Note: New Zealand switched back to standard time on April 6th – it’s currently Fall down under – and local sunrise occurs around ~7:40 AM.

Lambda Aquarii is a 3.6 solar mass star located 390 light years distant. As far as we know, it’s a solitary star, though there’s always a chance that a companion could make itself known as it emerges on the dark limb of Venus. Such an observation will, however, be extremely difficult, as Venus is still over 700 times brighter than the star!

North Americans get to see the pair only 20’ apart on the morning of the 12th.

Starry Night
One degree fields of view worldwide showing Venus and Lambda Aquarii at 7AM local. Credit: Starry Night.

And further occultation adventures await Venus in the 21st century. On October 1st, 2044 it will occult Regulus… and on November 22nd, 2065 it will actually occult Jupiter!

Such pairings give us a chance to image Venus with a “pseudo-moon.” Early telescopic observers made numerous sightings of a supposed Moon of Venus, and the hypothetical object even merited the name Neith for a brief time. Such sightings were most likely spurious internal reflections due to poor optics or nearby stars, but its fun to wonder what those observers of old might’ve seen.

… and speaking of moons, don’t miss a chance to see Venus near the daytime Moon April 25th. Follow us as @Astroguyz on Twitter as we give shout outs to these and other strange pairings daily!

Mars Opposition Season 2014: Images From Around the World

Mars as seen on from Aguadilla, Puerto Rico on Mars 25th, 2014, two weeks prior to opposition. Credit-Efrain Morales Rivera.

Did you see it? Last night, the Red Planet rose in the east as it passed opposition for 2014, and astrophotographers the world over were ready to greet it.  And although Mars gets slightly closer to us over the coming week, opposition marks the point at which Mars is 180 degrees “opposite” to the setting Sun in Right Ascension as viewed from our Earthly vantage point and denotes the center of the Mars observing season. Opposition only comes around once about every 26 months, so it’s definitely worth your while to check out Mars through a telescope now if you can. We’ve written about prospects for observing Mars this season, and the folks at Slooh and the Virtual Telescope Project also featured live views of the Red Planet last night. We also thought we’d include a reader roundup of pics from worldwide:

Mars and Spica rising over the telescope domes at Kitt Peak, Arizona. The 2.1 metre dome is on the left, and the 0.9 metre dome is to the right. Credit-Rob Sparks @halfastro
Mars and Spica rising over the telescope domes at Kitt Peak, Arizona. The 2.1 metre dome is on the left, and the 0.9 metre dome is to the right. Credit-Rob Sparks @halfastro.

Even near opposition, Mars presents a challenge to observers. In 2014, Mars only reaches 15 arc seconds maximum in apparent size, a far cry from its 25″ appearance during the historic 2003 opposition.  Now for the good news: we’re in a cycle of improving oppositions…  the next one on May 22nd, 2016 will be better still, and the 2018 opposition will be nearly as favorable as the 2003 appearance!

Mars as seen from the Netherlands at 0:26 UT... about 3 hours past opposition. Credit- Christian Fröschlin.
Mars as seen from the Netherlands at 0:26 UT… about 3 hours past opposition. Credit- Christian Fröschlin @chrfde.

And you can see just how technology in the amateur astronomy community has improved with each successive appearance of Mars over the years. Early observers were restricted to sketching features glimpsed during fleeting moments of steady seeing. Even during the film era of photography, absurdly long focal lengths were required to yield even a tiny speck of a dot. And even then, the “graininess” of the film tended to smear and yield a blurry image with few details to be seen.

The  advent of digital photography opened new vistas on planetary imaging. Now backyard astrophotographers are routinely taking images using stacking techniques and processing to “grab” and align those moments of good seeing. These images are often now better that what you’d see in a text book taken from professional observatories only a few decades ago!

And you can now easily modify a webcam to take decent planetary images that can then be stacked and processed with software freely available on the web.

…And check out this video animation also by Christian Fröschlin that shows the rotation (!) of Mars:

Mars as seen from Ottawa, Canada, taken using an IPhone 4S through a NexStar 8SE telescope on April 4th, 2014. Awesome! Credit-Andrew Symes @FailedProtostar
Mars as seen from Ottawa, Canada, taken using an IPhone 4S through a NexStar 8SE telescope on April 4th, 2014. Awesome! Credit-Andrew Symes @FailedProtostar

Shahrin Ahmad made an excellent video from Malaysia that demonstrates just what raw captured images of Mars look like before processing:

Note that the large dark triangular region is Syrtis Major.

Mars annotated, a stack of 1128 frames shot at 666x. Credit-Mike Weasner/Cassiopeia Observatory.
Mars annotated, a stack of 1128 frames shot at 666x. Credit-Mike Weasner/Cassiopeia Observatory.

The northern polar cap is currently tipped towards us, as it’s northern hemisphere summertime on Mars. Many images reflect this prominent feature, as well as the orographic clouds skirting the Hellas basin that have been the hallmark of the Mars opposition of 2014. These are also apparent visually at the eyepiece. It’s worth staying up a bit towards local midnight to observe and image Mars, as it transits at its maximum  elevation — and is above the murk of the sky low to the horizon — right around this time.

Mars captured through a Celestron C6 SCT telescope on April 5th, 2014. Credit: Joel Tonyan.
Mars captured through a Celestron C6 SCT telescope on April 5th, 2014. Credit: Joel Tonyan.
Mars: a study of color contrasts on the eve of opposition. Credit-Laura Austin @LAismylady
Mars: a study of color contrasts on the eve of opposition. Credit-Laura Austin @LAismylady

And Mars observing season doesn’t end this week. Mars makes its closest passage to the Earth for 2014 next Monday on April 14th at 0.618 Astronomical Units (A.U.s) distant. Mars will occupy the evening sky for the remainder of 2014 before finally reaching solar conjunction on June 14th, 2015. Mars will still be greater than a respectable 10″ in apparent size until June 24th and will continue to offer observers a fine view at the eyepiece.

Mars as seen from Rhode Island on the night of opposition. Credit-Cherie @KelieAna
Mars as seen from Rhode Island on the night of opposition. Credit-Cherie @KelieAna

And don’t forget, that waxing gibbous Moon is now homing in on Mars and will only sit a few degrees away from the Red Planet and Spica on the night of the April 14th/15th, 2014 during a fine total lunar eclipse. And no, a “red” planet + a “blood red” eclipsed Moon does not equal doomsday… but it’ll make a great photo op!

Mars imaged using a 150 mm scope. Credit-Sergei Golyshev under a Creative Commons Share-Alike 2.0 Generic License.
Mars imaged using a 150 mm scope. Credit-Sergei Golyshev under a Creative Commons Share-Alike 2.0 Generic License.

… and finally, Mars and the bright blue-white star Spica offered us a fine morning view as the storm front passed over Astroguyz HQ here in Florida this AM:

Author
Mars, Spica, and our partly cloudy terrestrial atmosphere. Photo by author.

Want something more? Have you ever seen Mars… in the daytime? Currently shining at magnitude -1.5, its just possible if you known exactly where to look for it low to the east about 10 minutes or so before local sunset. In fact, near opposition is the only time you can carry this unusual feat of visual athletics out. The best chance in 2014 is on the evening of April 13th and 14th, when the waxing gibbous Moon lies nearby:

Starry Night education software
Looking east on the evening of April 13th, just before sunset. Credit: Starry Night education software.

Good luck, and thanks to everyone who imaged Mars this season!

 

 

 

 

 

 

 

 

 

 

 

Why Universe Today Writes on Climate Change

n this rare image taken on July 19, 2013, the wide-angle camera on NASA's Cassini spacecraft has captured Saturn's rings and Earth in the same frame. Image Credit: NASA/JPL-Caltech/Space Science Institute

Online science reporting is difficult. Never mind the incredible amount of work each story requires from interviewing scientists to meticulously choosing the words you will use to describe a tough subject. That’s the fun part. It’s just after you hit the blue publish button, when the story goes live, that things get rough. Your readers will tear you apart. They will comment on any misplaced commas, a number with one too many significant figures, and an added space in between sentences. They will criticize and not compliment.

Now I’m not saying this isn’t welcome. By all means if I have misspoken, do let me know. I need to be on top of my game 100% of the time and readers’ comments help make that happen. They can improve an article tremendously, allowing readers to carry on the conversation and provide a richer context. Thought-provoking commenters always bring a smile to my face.

But then there’s online environmental reporting. From day one, reader comments made me realize that I needed to develop a thicker skin. I won’t go into the nasty details here, but in my most recent article, readers asked why Universe Today — an astronomy and space news site — would report on the science and even the politics regarding climate change. Well dear readers, I have heard you, and here is the answer to your question.

Universe Today is a dedicated space and astronomy news site. And I am proud to be a part of the team bringing readers up-to-date with the ongoings in our local universe. But that definition covers a wide variety of subjects, some might even say an infinite number of subjects.

On any given day authors from our team might write about subjects from planets within our solar system to distant galaxies. We want to better understand these celestial objects by focusing on their origin, evolution and fate. And in doing so we will discuss research that utilizes physics or chemistry, biology or astronomy. We might even write about politics, especially if NASA’s budget is involved.

I argue that writing about the Earth falls into the above category. After all, we do live on a planet that circles the Sun. And unlike Venus, where thick skies of carbon dioxide and even clouds of sulfuric acid make the surface incredibly difficult to see, we can directly study our surface, even run our fingers through the sand.

Intensive geologic surveys of the Earth below your feet help astronomers to understand the geology of other environments, including our nearest neighbor Venus and distant moons. We now know Enceladus has an ocean because of its combination of two compensating mass anomalies — an effect we see here on Earth. Perhaps one day this research will even help us understand geologic features on distant exoplanets.

Any study, which helps us better understand our home planet, whether it looks at plate tectonics or the sobering effects of global warming, exists under the encompassing umbrella of astronomy.

Now for my second, philosophical, argument. On the darkest of nights, thousands of stars compose the celestial sphere above us. The universe is boundless. It is infinite. We stand on but one out of 100 billion (if not more) planets in the Milky Way galaxy alone, which in turn, is but one out of 100 billion galaxies in the observable universe. We live in complete isolation. It’s both humbling and awe-inspiring.

Carl Sagan was the first to coin the phrase “pale blue dot” and in his words:

“Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.”

Sagan argues that we have the moral duty to protect our home planet. This sense of obligation stems from the humble lessons gained from astronomy. So if Universe Today is not the appropriate platform to write about climate change I’m not sure what is.

All comments welcome.

The USAF’s Super-Secret X-37B Approaches a Milestone

An artists' conception of the X-37B in Earth orbit. Credit: The U.S. Air Force.

A secretive mission will pass a quiet milestone at the end of this month when the U.S. Air Force’s unmanned spaceplane the X-37B surpasses 500 days in space.

Launched atop an Atlas V rocket flying in a 401 configuration from Cape Canaveral Florida after several delays on December 11th, 2012 on OTV-3, the X-37B has already surpassed its own record of 469 days in space set on OTV-2. Said milestone was crossed last month. If the current mission stays in space until April 25th of this year, it will have surpassed 500 days in space.

Two X-37Bs were built for the USAF, and the first test mission flew in 2010. NASA performed drop glide tests with an early variant of the X-37A in 2005 and 2006, and DARPA is thought to be a primary customer for the program as well.

Measuring just 8.8 metres in length, the X-37B is tiny compared to its more famous spaceplane cousin the U.S. Space Shuttle. The X-37B has a maximum weight at liftoff of 4,990 kilograms and features a payload bay 2.1 by 1.2 metres in size.

The spacecraft itself is solar powered, as it unfurls a panel — as depicted in many artists’ conceptions — once it’s in orbit. Of course, its mission profile is classified, and the X-37B could land unannounced at any time. The previous landings occurred at Vandenberg Air Force Base in California and were only announced shortly thereafter.

Not only is this the longest continuous mission for any spaceplane,  but the ATV-3 is also the smallest, lightest and only the second spaceplane to land autonomously, the first being the Russian space shuttle Buran that flew one mission and landed after one orbit at the Baikonur Cosmodrome on November 15th, 1988.

The X-37B awaiting encapsulation for launch. Credit: U.S. Air Force.
The X-37B awaiting encapsulation for launch. Credit: U.S. Air Force.

The idea of a reusable spaceplane has been around since the dawn of the Space Age. The U.S. Space Shuttle program was the most high profile of these, having flown 135 missions from 1981 to 2011. But even the space shuttle launch system wasn’t fully reusable, expending its large orange external fuel tank after every mission and requiring extensive refurbishment for the solid rocket motors and orbiter after each and every flight. The Soviets abandoned Buran in 1988, and other examples of spaceplanes such as North American’s X-15 surpassed the 100 kilometre in altitude Kármán line marking the boundary to space, but were suborbital only. And this year, customers may get a chance to make similar suborbital hops into space aboard Virgin Galactic’s SpaceShipTwo spaceplane at $250,000 dollars a ticket.

But the most ambitious design for a true spaceplane was conceived in the 1960’s: Boeing’s X-20 Dyna-Soar, which was never built.

Classified satellites such as the X-37B are part of a longstanding and fascinating “secret space race” that has paralleled and shadowed the more well known space programs of various nations over the decades. These include the Corona program which ran from 1959 to 1972 and was only declassified in 1995, and satellites such as Lacrosse 5, which is notorious among satellite sleuths for the orbital “vanishing act” it sometimes pulls.

And speaking of which, you can track the X-37B from your backyard, tonight. Ground spotters first pegged its position in low Earth orbit during OTV-1 on May 22nd 2010, and the spacecraft currently sits in a 392 x 296 kilometre (nearly circular) orbit in an 43.5 degree inclination, making it visible from latitudes 55 degrees north to south. On a favorable overhead pass, the X-37B is easily visible shining at greater than magnitude +1. OTV-3’s NORAD ID designation is 39025 or 2012-071A, and although – like most classified payloads – it’s not available to the public on Space-Track, Heavens-Above does list upcoming sighting opportunities. Be sure to start watching a bit early, as the X-37B has been known to maneuver a bit in its orbit on occasion.

Of course, just what the X-37B is doing in orbit is anybody’s guess. Speculation is that it’s serving as a test bed for new technologies. Certainly, the ability to place interchangeable payloads in orbit is immediately apparent. It’s also worth noting that the X-37B makes multiple daily passes on its northward apex over North Korea and China. There’s also been speculation that the X-37B was designed to keep tabs on the Chinese space station Tiangong-1, although this can easily be refuted as they both lie in different orbits. There’s no word as to what’s to become of Tiangong-1, though China had said it was set to deorbit the station at the end of 2013, and it is still in space.

Looking ahead into the future, there has been talk about a larger crewed variant known as the X-37C, which will undoubtedly fly much shorter missions. For now, we can watch and wonder what it’s up to, as the X-37B glides silently overhead. Perhaps one day, its mission will declassified, and its tale can be told.

-For more info sat-tracking, check out our how-to post and also read about the fascinating true role that amateurs played during the Cold War and Operation Moonwatch.

 

Comet Jacques Brightens Rapidly, Heads North

omet C/2014 E2 Jacques on April 1, 2014. Credit and copyright: Damian Peach.

We’ve got a hot comet on our hands. Comet Jacques barely cracked magnitude +11 at the time of its March 13 discovery, but just three weeks later, amateur astronomers have already spotted it in large binoculars at magnitude +9.5. Expert comet observer Michael Mattiazzo, who maintains the Southern Comets Homepage, predicts that if Comet Jacques continues its rapid rise in brightness, it might become faintly visible with the naked eye by July. 

Discovery images of Comet Jacques by the SONEAR team show a small, condensed object with a short, faint tail. Credit: SONEAR
Discovery images of Comet Jacques by the SONEAR team show a small, condensed object with a short, faint tail. Credit: SONEAR

The comet’s currently inching across the southern constellation Antlia  headed toward Puppis and Monoceros later this month. Observers describe it as “very diffuse” with a large, dim coma and moderately compact core. Photos show a short tail pointing east-northeast. This past weekend C/2014 E2 passed closest to the Earth at 89.3 million miles (144 million km) on its way to perihelion on July 2.

Comet Jacques photographed on April 3, 2014. Credit: Efrain Morales
Comet Jacques photographed on April 3, 2014 when it was near two faint galaxies. Credit: Efrain Morales

Right now, observers in southern latitudes have the viewing advantage. As seen from South America and Australia, Comet Jacques floats high in the southwestern sky at nightfall. Observers in mid-northern latitudes can see it too, but have to set their sights lower.  A week ago I tried tracking down this newcomer with a 37-cm (15-inch) Dobsonian reflector around 9 o’clock. With Jacques only 14 degrees high at the time I had to kneel beside the telescope to see into the eyepiece. Try as I might, I suspected only a fuzzy patch at best. Light pollution and low altitude were partly to blame, but Jacques’ diffuse appearance may have contributed to the uncertain observation.  Other mid-northern latitude observers may have shared my sore kneecap experience in similar attempts.

Map showing Comet Jacques starting April 16 when the moon is once again out of the evening sky. Positions are shown every 5 days through May 16. Created with Chris Mariott's SkyMap software
Map dated April 16 showing Comet Jacques’ path from mid-April to mid-May. Positions are marked every 5 days with stars down to magnitude +8. Click to enlarge. Created with Chris Mariott’s SkyMap software

But that will soon change. C/2014 E2 continues to increase in altitude throughout the month, offering easier viewing as soon as mid-month.  April 16 through early May the moon will be gone from the sky and provide a needed dark time slot for viewing the comet before it’s lost in evening twilight. Comet Jacques will likely be brighter than magnitude 9 as it slides from Puppis into Monoceros.

Find a place with a dark sky to the southwest and start looking at the end of evening twilight when the comet is highest. The map shows stars in reverse making it easier to use in crowded star fields.

Comet Jacques is approaching the sun from beneath (south of) the plane of the planets indicated by the dark blue curve of its orbit. It crosses northward later this spring (Iight blue). Credit: NASA/JPL
Comet Jacques is approaching the sun from beneath (south of) the plane of the planets indicated by the dark blue curve of its orbit. It crosses northward later this spring (Iight blue). Credit: NASA/JPL

By mid-July, Comet Jacques will have passed perihelion 61 million miles (98 million km) from the sun and transition into the morning sky as it rapidly swings northward across Taurus, Auriga and Perseus. Though the comet will be half again as far from Earth as it is today, it’s expected to become considerably brighter and more condensed after a good “roasting” by the sun.

C/2012 E2 will join a veritable team of comets expected to reach or approach naked eye brightness in late summer and fall: C/2012 K1 PANSTARRS, C/2013 A1 Siding Spring and C/2013 V5 Oukaimeden. Much to look forward to!

The Science Behind the “Blood Moon Tetrad” and Why Lunar Eclipses Don’t Mean the End of the World

A mosaic of the 2003 total lunar eclipse. photos by author.

 By now, you may have already heard the latest tale of gloom and doom surrounding the upcoming series of lunar eclipses.

This latest “End of the World of the Week” comes to us in what’s being termed as a “Blood Moon,” and it’s an internet meme that’s elicited enough questions from friends, family and random people on Twitter that it merits addressing from an astronomical perspective.

Like the hysteria surrounding the supposed Mayan prophecy back in 2012 and Comet ISON last year, the purveyors of Blood Moon lunacy offer a pretty mixed and often contradictory bag when it comes down to actually what will occur.

But just like during the Mayan apocalypse nonsense, you didn’t have to tally up just how many Piktuns are in a Baktun to smell a rat. December 21st 2012 came and went, the galactic core roughly aligned with the solstice — just like it does every year — and the end of the world types slithered back into their holes to look for something else produce more dubious YouTube videos about.

Here’s the gist of what’s got some folks wound up about the upcoming cycle of eclipses. The April 15th total lunar eclipse is the first in series of four total eclipses spanning back-to-back years, known as a tetrad. There are eight tetrads in the 21st century: if you observed the set total lunar eclipses back in 2003 and 2004, you saw the first tetrad of the 21st century.

The eclipses in this particular tetrad, however, coincide with the Full Moon marking Passover on April 15th and April 4th and the Jewish observance of Sukkot on October 8th and September 28th. Many then go on to cite the cryptic biblical verse from Revelation 6:12, which states;

“I watched as he opened the sixth seal. There was a great earthquake. The Sun turned black like sackcloth made of goat hair. The whole Moon turned blood red.”

Whoa, some scary allegory, indeed… but does this mean the end of the world is nigh?

I wouldn’t charge that credit card through the roof just yet.

First off, looking at the eclipse tetrads for the 21st century, we see that they’re not really all that rare:

21st century eclipse tetrads:

Eclipse #1 Eclipse #2 Eclipse #3 Eclipse #4
May 16th, 2003 November 9th, 2003 May 4th , 2004 October 28th, 2004
April 15th, 2014*+ October 8th, 2014 April  4th, 2015*+ September 28th, 2015
April 25th, 2032 October 18th, 2032 April 14th, 2033*+ October 8th, 2033
March 25th, 2043* September 19th, 2043 March 13th, 2044 September 7th, 2044
May 6th, 2050 October 30th, 2050 April 26th, 2051 October 19th, 2051
April  4th, 2061*+ September 29th, 2061 March 25th, 2062* September  18th, 2062
March 4th, 2072 August 28th, 2072 February 22nd, 2073 August 17th, 2073
March 15th, 2090 September 8th, 2090 March 5th, 2091 August 29th, 2091
*Paschal Full Moon
+Eclipse coincides with Passover

 

Furthermore, Passover is always marked by a Full Moon, and a lunar eclipse always coincides with a Full Moon by definition, meaning it cannot occur at any other phase. The Jewish calendar is a luni-solar based calendar that attempts to mark the passage of astronomical time via the apparent course that the Sun and the Moon tracks through the sky. The Muslim calendar is an example of a strictly lunar calendar, and our western Gregorian calendar is an example of a straight up solar one. The Full Moon marking Passover often, though not always, coincides with the Paschal Moon heralding Easter. And for that matter, Passover actually starts at sunset the evening prior in 2014 on April 14th. Easter is reckoned as the Sunday after the Full Moon falling after March 21st which is the date the Catholic Church fixes as the vernal equinox, though in this current decade, it falls on March 20th. Easter can therefore fall anywhere from March 22nd to April 25th, and in 2014 falls on the late-ish side, on April 20th.

To achieve synchrony, the Jewish calendar must add what’s known as embolismic or intercalculary months (a second month of Adar) every few years, which in fact it did just last month. Eclipses happen, and sometimes they occur on Passover. It’s rare that they pop up on tetrad cycles, yes, but it’s at best a mathematical curiosity that is a result of our attempt to keep our various calendrical systems in sync with the heavens.  It’s interesting to check out the tally of total eclipses versus tetrads over a two millennium span:

Century Number of Total Lunar Eclipses Number of Tetrads Century Number of Total Lunar Eclipses Number of Tetrads
11th

62

0

21st

85

8

12th

59

0

22nd

69

4

13th

60

0

23rd

61

0

14th

77

6

24th

60

0

15th

83

4

25th

69

4

16th

77

6

26th

87

8

17th

61

0

27th

79

7

18th

60

0

28th

64

0

19th

62

0

29th

57

0

20th

81

5

30th

63

1

 

Note that over a five millennium span from 1999 BC to 3000 AD, the max number of eclipse tetrads that any century can have is 8, which occurs this century and last happened in the 9th century AD.

Of course, the visual appearance of a “Blood of the Moon” that’s possibly alluded to in Revelation is a real phenomena that you can see next week from North and South America as the Moon enters into the dark umbra or core of the shadow of the Earth. But this occurs during every total lunar eclipse, and the redness of the Moon is simply due to the scattering of sunlight through the Earth’s atmosphere. Incidentally, this redness can vary considerably due to the amount of dust, ash, and particulate aerosols aloft in the Earth’s atmosphere, resulting in anything from a bright cherry red eclipse during totality to an eclipsed Moon almost disappearing from view altogether… but it’s well understood by science and not at all supernatural.

The changing colors of a lunar eclipse: a mosaic of four eclipses. Photos by author.
The changing colors of a lunar eclipse: a mosaic of four eclipses. Photos by author.

Curiously, the Revelation passage could be read to mean a total solar eclipse as well, though both can never happen on the same day.  Lunar and solar eclipses occur in pairs two weeks apart at Full and New Moon phases when the nodes of the Moon’s ecliptic crossing comes into alignment with the Sun — known as a syzygy, an ultimate triple word score in Scrabble, by the way — and this eclipse season sees a non-central annular eclipse following the April 15th eclipse on April 29th.

And yes, earthquakes, wars, disease, relationship breakups and lost car keys are on tap to occur in 2014 and 2015… just like during any other year. Lunar eclipses marked the fall of Constantinople in 1453 and the World Series victory of the Red Sox in 2004, but they’re far from rare. We humans love to see patterns, and sometimes this habit works against us, making us see them where none exists. This is simply a case of the gambler’s fallacy, counting the hits at the cost of the misses. We could just as easily make a case that the upcoming eclipse tetrad of April 15th, October 8th, April 4th and September 28th marks US Tax Day, Croatian Independence Day, The Feast of Benedict of the Moor & — Michael Scott take note — International World Rabies Day… perhaps the final 2015 eclipse should be known as a “Rabies Moon?”

So, what’s the harm in believing in a little gloom and doom? The harm in believing the world ends tomorrow comes when we fail to plan for still being here the day after. The harm comes when something like the Heavens Gate mass suicide goes down. We are indeed linked to the universe, but not in the mundane and trivial way that astrologers and doomsdayers would have you believe. Science shows us where we came from and where we might be headed.  We’ve already fielded queries from folks asking if it’s safe (!) to stare at the Blood Moon during the eclipse, and the answer is yes… don’t give in to superstition and miss out on this spectacular show of nature because of some internet nonsense.

The upcoming lunar eclipse next week won’t mean the end of the world for anyone, except, perhaps, NASA’s LADEE spacecraft… be sure not to miss it!

 

Quasars Tell The Story Of How Fast The Young Universe Expanded

Artist's conception of how the Baryon Oscillation Spectroscopic Survey uses quasars to make measurements. The light these objects sends out gets absorbed by gas in between the receiver and the source. The gas is then "imprinted wiht a subtle ring-like pattern of known physical scale", the Sloan Digital Sky Survey stated. Credit: Zosia Rostomian (Lawrence Berkeley National Laboratory) and Andreu Font-Ribera (BOSS Lyman-alpha team, Berkeley Lab.)

For those who saw the Cosmos episode on William Herschel describing telescopes as time machines, here is a clear example of that. By examining 140,000 objects called quasars (galaxies with an active black hole at their centers), astronomers have charted the expansion rate of the universe — not now, but 10.8 billion years ago.

This is the most precise measurement ever of the universe’s expansion rate at any point in time, the science teams said, with the calculation showing the universe was expanding by 1% every 44 million years at that time. (That figure is to 2% precision, the researchers added.)

“If we look back to the Universe when galaxies were three times closer together than they are today, we’d see that a pair of galaxies separated by a million light-years would be drifting apart at a speed of 68 kilometers per second as the Universe expands,” stated Andreu Font-Ribera of the Lawrence Berkeley National Laboratory, who led one of the two analyses.

The researchers used a telescope called the Sloan Digital Sky Survey, a 2.5-meter telescope at Apache Point Observatory in New Mexico. The discovery was made during Sloan’s Baryon Oscillation Spectroscopic Survey, or BOSS, whose aim has been to figure out the expansion and acceleration of the universe.

The accelerating, expanding Universe. Credit: NASA/WMAP
The accelerating, expanding Universe. Credit: NASA/WMAP

“BOSS determines the expansion rate at a given time in the Universe by measuring the size of baryon acoustic oscillations (BAO), a signature imprinted in the way matter is distributed, resulting from sound waves in the early Universe,” the Sloan Digital Sky Survey stated. “This imprint is visible in the distribution of galaxies, quasars, and intergalactic hydrogen throughout the cosmos.”

Font-Ribera and his collaborators examined how quasars are distributed compared to hydrogen gas to calculate distance. The other analysis, led by Timothée Delubac (Centre de Saclay, France), examined the hydrogen gas to see patterns and measure mass distribution.

You can read more about Font-Ribera’s team’s research in preprint version on Arxiv. Delubac’s research does not appear to be available online, but the title is “Baryon Acoustic Oscillations in the Ly-alpha forest of BOSS DR11 quasars” and it has been submitted to Astronomy & Astrophysics.

Source: Sloan Digital Sky Survey

El Gordo Galaxy Cluster Even Bigger Than Thought

Hubble Space Telescope image of the El Gordo galaxy cluster. This and other gigantic galaxy clusters are challenging the most common theory of the evolution of structure in the Universe. Credit: NASA, ESA, and J. Jee (University of California, Davis)
Hubble Space Telescope image of the El Gordo galaxy cluster. This and other gigantic galaxy clusters are challenging the most common theory of the evolution of structure in the Universe. Credit: NASA, ESA, and J. Jee (University of California, Davis)

 

The Hubble Space Telescope has a new calculation for the huge El Gordo galaxy cluster: 3 million billion times the mass of the Sun. This is even 43 per cent more massive than past estimates that examined the complex in X-rays, NASA stated.

“A fraction of this mass is locked up in several hundred galaxies that inhabit the cluster and a larger fraction is in hot gas that fills the entire volume of the cluster. The rest is tied up in dark matter, an invisible form of matter that makes up the bulk of the mass of the universe,” the Space Telescope Science Institute stated.

“Though galaxy clusters as massive are found in the nearby universe, such as the so-called Bullet Cluster, nothing like this has ever been seen to exist so far back in time, when the universe was roughly half of its current age of 13.8 billion years. The team suspects such monsters are rare in the early universe, based on current cosmological models.”

Read more about the discovery in this Hubble press release.