Hunting for “Minimoons” Orbiting Earth

Credit: Used with permission

It’s an engaging thought experiment.

What if Earth had multiple moons?  Our world has one large natural satellite, just over a quarter the diameter, 1/50th the volume, and less than 1/80th the mass of our fair world. In fact, the Earth-Moon system has sometimes been referred to as a “binary planet,” and our Moon stands as the largest natural satellite of any planet — that is, if you subscribe to bouncing Pluto and Charon out of “the club” — in contrast to its primary of any moon in our solar system.

But what if we had two or more moons? And are there any tiny “moonlet” candidates lurking out there, awaiting discovery and perhaps exploration?

While historical searches for tiny secondary moons of the Earth — and even “moons of our Moon” — have turned up naught, the Earth does indeed capture asteroids as temporary moons and eject them back into solar orbit from time to time.

Now, a recent paper out of the University of Hawaii written in partnership with the SETI Institute and the Department of Physics at the University of Helsinki has looked at the possible prospects for the population of captured Near-Earth asteroids, and the feasibility of detecting these with existing and future systems about to come online.

The hunt for spurious moons of the Earth has a fascinating and largely untold history. Arthur Upgren’s outstanding book Many Skies devotes an entire chapter to the possible ramifications of an Earth with multiple moons… sure, more moons would be a bane for astrophotographers, but hey, eclipses and transits of the Sun would be more common, a definite plus.

In 1846, astronomer Frederic Petit announced the discovery of a tiny Earth-orbiting moon from Toulouse observatory. “Petit’s Moon” was said to orbit the Earth once every 2 hours and 44 minutes and reach an apogee of 3,570 kilometres and a perigee of just 11.4 (!) kilometres, placing it well inside the Earth’s atmosphere on closest approach.

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The announcement (in German) of the discovery of Waltemath’s Moon. “Ein zweiter Mond der Erde” translates into “a second Earth moon.” Credit: Wikimedia Commons image in the public domain.

A slightly more believable claim came from astronomer Georg Waltemath in 1898 for a moon 700 kilometres in size — he claimed it was, of course, a very dark body and not very easily visible — orbiting the Earth at about 2.5 times the distance of the Moon. Waltemath even made an announcement of his discovery, and claimed to have found a third moon of the Earth for good measure.

And a much more dubious claim came from the astrologer Walter Gornold in 1918 of a secondary moon, dubbed Lilith. Apparently, then (as now) astrologers never actually bothered to look at the skies…

Turns out, our large Moon makes a pretty good goaltender, ejecting —and sometimes taking a beating from — any tiny second moon hopeful. Of course, you can’t blame those astronomers of yore entirely. Though none of these spurious moons survived the test of observational verification, these discoveries often stemmed from early efforts to accurately predict the precise motion of the Moon. Astronomers therefore felt they were on the right track, looking for an unseen perturbing body.

Fast forward to the 21st century. Quasi-moons of the Earth, such as 3753 Cruithne, have horseshoe-shaped orbits and seem to approach and recede from our planet as both orbit the Sun. Similar quasi-moons of Venus have also been discovered.

And even returning space junk can masquerade as a moon of Earth, as was the case of J002E3 and 2010 QW1, which turned out to be boosters from Apollo 12 and the Chinese Chang’e-2 missions, respectively.

What modern researchers are looking for are termed Temporarily Captured Orbiters, or TCOs. The study notes that perhaps an average of a few dozen asteroids up to 1 to 2 metres in size are in a “steady state” population that may be orbiting the Earth at any given time on an enter, orbit, and eject sort of conveyor belt. Estimates suggest that a large 5 to 10 metre asteroid is captured every decade so, and a 100 metre or larger TCO is temporarily captured by the Earth every 100,000 years. The study also estimates that about 1% occasionally hit the Earth. And though it wasn’t a TCO, the ability to detect an Earthbound asteroid before impact was demonstrated in 2008 with the discovery of 2008 TC3, less than 24 hours prior to striking in the Sudanese desert.

“There are currently no projects that are solely looking for minimoons at this time,” lead researcher Bryce Bolin of the University of Hawaii told Universe Today. “There are several surveys, such as PanSTARRS, the Catalina Sky Survey and the Palomar Transit Factory that are currently in operation that have the capability of discovering minimoons.”

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The convoluted orbit of 2006 RH120 around the Earth-Moon system, to date the only confirmed TCO. Credit: Wikimedia Commons/Ohms law.

We’re getting better at this hazardous asteroid detection business, that’s for sure. The researchers modeled paths and orbits for TCOs in the study, and also noted that collections may “clump” at the anti-sunward L2 opposition point, and the L1 sunward point, with smaller distributions located at the east and west quadrature points located 90 degrees on either side of the Earth. The L2 point in particular might make a good place to start the search.

Ironically, systems such as LINEAR and PanSTARRS may have already captured a TCO in their data and disregarded them in their quest for traditional Near Earth Objects.

“Surveys such as PanSTARRS/LINEAR utilize a filtration process to remove artifacts and false positives in the data as it gets processed through the data pipeline,” Researcher Bryce Bolin told Universe Today. “A common method is to apply a rate of motion cut… this is effective in eliminating many artifacts (which) tend to have a rate of motion as measured by the pipeline which is very high.”

Such systems aren’t always looking for fast movers near Earth orbit that can produce a trail or streak which may reassemble space junk or become lost in the gaps over multiple detection devices. And speaking of which, researchers note that Arecibo and the U.S. Air Force’s Space Surveillance System may be recruited in this effort as well. To date, one definite TCO, named 2006 RH120 has been documented orbiting and departing from the vicinity of the Earth, and such worldlets might make enticing targets for future manned missions due to their relatively low Delta-V for arrival and departure.

Future asteroid mission. Credit: NASA
An artist’s concept of a possible future asteroid mission near Earth. Credit: NASA.

PanSTARRS-2 saw first light last year in 2013, and is slated to go online for full science operations by the end of 2014. Eventually, the PanSTARRS system will employ four telescopes, and may find a bevy of TCOs. The researchers estimate in the study that a telescope such as Subaru stands a 90% chance of nabbing a TCO after only five nights of dedicated sweeps of the sky.

Finally, the study also notes that evidence miniature moonlets orbiting Earth may lurk in the all sky data gathered by automated cameras and amateur observers during meteor showers.  Of course, we’re talking tiny, dust-to-pebble sized evidence, but there’s no lower limit as to what constitutes a moon…

And so, although moons such a “Lilith” and “Petit’s Moon” belong to the annuals of astronomical history, temporary “minimoons” of Earth are modern realities. And as events such as Chelyabinsk remind us, it’s always worthwhile to hunt for hazardous NEOs (and TCOs) that may be headed our way. Hey, to paraphrase science fiction author Larry Niven: unlike the dinosaurs, we have a space program!

Read more about the fascinating history of moons that never were and more in the classic book The Haunted Observatory.

Astronomy History and Future Come Together at the South Carolina State Museum

Credit South Carolina Museum

Seeking out science and astronomy in South Carolina? You’re in luck, as we’re pleased to report the South Carolina State Museum’s brand-spanking new planetarium and astronomical observatory opened to the public earlier this month. Part of a 75,000 square foot expansion project dubbed Windows to New Worlds, the renovation puts the museum on the cutting edge of STEM education and public outreach. And not only does the new expansion include one of the largest planetariums in the southeastern U.S., but it also features the only 4D theater in the state of South Carolina. The observatory, planetarium and brand new exhibits present a fascinating blend of the grandeur of astronomical history and modern technology.

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Exploring the universe… Credit: South Carolina State Museum/Sean Rayford.

“What we have built represents a quantum leap forward for South Carolina in the areas of cultural tourism, recreation and especially education,” said executive director of the South Carolina State Museum Willie Calloway in a recent press release. “Our new facility is building opportunity — opportunity for students to thrive, opportunity for our economy to grow and opportunity for our guests to be entertained in new ways.”

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The 12 3/8″ refractor prior to installation in the observatory. Photo by author.

We first visited the South Carolina State Museum in 2012 when plans for the planetarium and observatory were just starting to come together. The large Alvan Clark refractor now in the observatory was on display in the main museum, but much of the telescopes in the museum’s collection of antique instruments and gear were yet to be seen by the public.

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A collection of eyepieces and adapters from the Robert Ariail collection. Photo by author.

We firmly believe that a telescope out under the night sky is a happy telescope, and it’s great to see the old 12 3/8” Alvan Clark refractor in action once again!

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A brass solar “flip” adapter. Photo by author.

The expansion also includes a new display for the Robert Ariail collection, a fascinating assortment of astronomical instruments dating back to 1730. A highlight of the display is a 5.6-inch refractor designed by American optician and telescope maker Henry Fitz in 1849 for Erskine College. This stands as the oldest surviving American manufactured telescope known. The Robert Ariail collection is one of the largest collections of antique refracting telescopes in the world. We were amazed at the array of old solar projectors and filters, including some that we could not immediately identify.

Just how did some of those astronomers of yore observe the Sun other than projection? In some cases, they used smoked glass… but often, we learned at our behind the scenes tour at the South Carolina State museum in Columbia that they observed the Sun through an adapter filled with dark oil. No, don’t try this inconsistent and incredibly dangerous method of solar observing at home! We also noted that several of the solar filters were cracked, which no doubt occurred while they were in use.

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A “solar tube”. Note the word SUN on the side and the heat baffles in the back! Photo by author.

The Planetarium: The new planetarium is known officially as the BlueCross/BlueShield of South Carolina Planetarium, and the new 55-foot diameter digital dome seats 145 and is now running shows that cover art, science, history and — of course — astronomy. Laser light shows set to a modern rock soundtrack —cue pink Floyd’s Dark Side of the Moon, sides one and two — are also planned. And don’t miss the NASA gallery in the lobby to the planetarium which features artifacts from South Carolina hometown astronauts Frank Culbertson, Ron McNair, Charles Duke and Charles Bolden.

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The Robert Ariail collection on display. Credit: The South Carolina State Museum/Brett Flashnick.

The Observatory: The Boeing Astronomical Observatory is now open for business and features the aforementioned Alvan Clark 12 3/8-inch refracting telescope. Built in 1926, this grand old refractor bespeaks of a bygone era when astronomers actually looked through telescopes, pipe in hand, atop some distant windswept mountain. Squint hard, and maybe you’ll spy a canal festooned Mars… OK, maybe that’s a stretch, but it’s amazing to look through one of these grand old instruments, in person. And the observatory is the only one of its kind in the United States (and perhaps the world) that will offer modern remote access to an antique telescope to classroom students.

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The observatory exterior at night. Credit: The South Carolina State Museum/Sean Rayford.

The observatory also includes a classroom, outdoor viewing terrace, and a modern state-of-the-art computer control system that those old “astronomers of yore” only wish that they’d had, especially when they had to manually crank up the mechanical counterweights on their clock drives!

Not only is the observatory open for night viewing — and just in time for the upcoming October 8th total lunar eclipse — but they’re also open to the public for daily solar observing sessions as well. And we promise they’re utilizing the very latest in solar safety technology… no overheating oil-filled filters allowed!

The 2017 total solar eclipse and the future: But there’s another reason to visit Columbia South Carolina about three years hence: the city and the South Carolina State Museum will once again be the center of astronomical action in less than three years time, when a total solar eclipse crosses the state from the northwest to the southeast on august 21st, 2017. Towns across the United States are already preparing for this celestial spectacle, and Columbia is one of the largest cities along its path. It promises to be a great show!

Don’t miss these exciting goings on in Columbia, South Carolina… the new planetarium and observatory is truly “brighter than ever” and out of this world!

Follow the South Carolina State Museum as @SCStateMuseum and the hashtags #scsm and #BrighterThanEver.

James Webb Space Telescope’s Giant Sunshield Test Unit Unfurled First Time

The sunshield test unit on NASA's James Webb Space Telescope is unfurled for the first time. Credit: NASA

GODDARD SPACE FLIGHT CENTER, MD – The huge Sunshield test unit for NASA’s James Webb Space Telescope (JWST) has been successfully unfurled for the first time in a key milestone ahead of the launch scheduled for October 2018.

Engineers stacked and expanded the tennis-court sized Sunshield test unit last week inside the cleanroom at a Northrop Grumman facility in Redondo Beach, California.

NASA reports that the operation proceeded perfectly the first time during the test of the full-sized unit.

The Sunshield and every other JWST component must unfold perfectly and to precise tolerances in space because it has not been designed for servicing or repairs by astronaut crews voyaging beyond low-Earth orbit into deep space, William Ochs, Associate Director for JWST at NASA Goddard told me in an exclusive interview.

Artist’s concept of the James Webb Space Telescope (JWST) with Sunshield at bottom.  Credit: NASA/ESA
Artist’s concept of the James Webb Space Telescope (JWST) with Sunshield at bottom. Credit: NASA/ESA

The five layered Sunshield is the largest component of the observatory and acts like a parasol.

Its purpose is to protect Webb from the suns heat and passively cool the telescope and its quartet of sensitive science instruments via permanent shade to approximately 45 kelvins, -380 degrees F, -233 C.

The kite-shaped Sunshield provides an effective sun protection factor or SPF of 1,000,000. By comparison suntan lotion for humans has an SPF of 8 to 40.

Two sides of the James Webb Space Telescope (JWST). Credit: NASA
Two sides of the James Webb Space Telescope (JWST). Credit: NASA

The extreme cold is required for the telescope to function in the infrared (IR) wavelengths and enable it to look back in time further than ever before to detect distant objects.

The shield separates the observatory into a warm sun-facing side and a cold anti-sun side.

Its five thin membrane layers also provides a stable thermal environment to keep the telescopes 18 primary mirror segments properly aligned for Webb’s science investigations.

JWST is the successor to the 24 year old Hubble Space Telescope and will become the most powerful telescope ever sent to space.

The Webb Telescope is a joint international collaborative project between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).

NASA has overall responsibility and Northrop Grumman is the prime contractor for JWST.

Webb will launch folded up inside the payload fairing of an ESA Ariane V ECA rocket from the Guiana Space Center in Kourou, French Guiana.

In launch configuration, the Sunshield will surround the main mirrors and instruments like an umbrella.

During the post launch journey to the L2 observing orbit at the second Sun-Earth Lagrange point nearly a million miles (1.5 million Km) from Earth, the telescopes mirrors and sunshield will begin a rather complex six month long unfolding and calibration process.

The science instruments have been mounted inside the ISIM science module and are currently undergoing critical vacuum chamber testing at NASA Goddard Space Flight Center which provides overall management and systems engineering.

Gold coated flight spare of a JWST primary mirror segment made of beryllium and used for test operations inside the NASA Goddard clean room.  Credit: Ken Kremer- kenkremer.com
Gold coated flight spare of a JWST primary mirror segment made of beryllium and used for test operations inside the NASA Goddard clean room. Credit: Ken Kremer- kenkremer.com

The mirror segments have arrived at NASA Goddard where I’ve had the opportunity to observe and report on work in progress.

Stay tuned here for Ken’s continuing JWST, MMS, ISS, Curiosity, Opportunity, SpaceX, Orbital Sciences, Boeing, Orion, MAVEN, MOM, Mars and more Earth and Planetary science and human spaceflight news.

Ken Kremer

Sunshield test unit on NASA's James Webb Space Telescope is unfurled for the first time at Northrup Grumman.  Credit: NASA
Sunshield test unit on NASA’s James Webb Space Telescope is unfurled for the first time at Northrup Grumman. Credit: NASA

Having Fun with the Equation of Time

An analemma of the Sun, taken from Budapest, Hungary over a one year span. (Courtesy of György Soponyai, used with permission).

If you’re like us, you might’ve looked at a globe of the Earth in elementary school long before the days of Google Earth and wondered just what that strange looking figure eight thing on its side was.

Chances are, your teacher had no idea either, and you got an answer such as “it’s a calendar, kid” based on the months of the year marking its border.

In a vague sense, this answer is correct… sort of. That funky figure eight is what’s known as an analemma, and it traces out the course of the Sun in the sky through the year as measured from a daily point fixed in apparent solar time.

Analemma (Wikimedia Commons image).
Ye ole analemma… perpetually lost in the South Pacific? (Wikimedia Commons image).

But try explaining that one to your 3rd grade teacher. Turns out, measuring the passage of time isn’t as straight forward as you’d think. Our modern day clock and calendar is a sort of compromise, a method of marking the passage of time in a continuing battle to stay in sync with the heavens.

For most of history, the daily passage of time was denoted by the Sun. Solar Noon occurs when the Sun stands at its highest elevation (also known as its altitude) above the local horizon when it transits the north-south meridian. The trouble is, the passage apparent solar time doesn’t exactly match what we call solar mean time, or the 24 hour rotation of the Earth. In fact, this discrepancy can add up to as much as more than 16 minutes ahead of solar noon in late October and November and over 12 minutes behind it in February. This is worth bringing up this week because this factor, known as “The Equation of Time” — think “equation” in the sense that sundial owners must factor it in to make solar mean and apparent time “equal” — reaches its shallow minimum for 2014 this Saturday at 7:00 UT/3:00 AM EDT with a value of -6.54 minutes.

The solar analemma as plotted from the latitude of the Greenwich Observatory in England. (Wikimedia Commons/PAR/JPL Horizons).
The solar analemma as plotted from the latitude of the Greenwich Observatory in England. (Wikimedia Commons/PAR/JPL Horizons).

So, what gives? Why won’t the pesky universe stay in sync?

Well, the discrepancy arises from two factors: the eccentricity of the Earth’s orbit, or how much it deviates from circular and the obliquity of the ecliptic to the celestial equator, think the tilt of Earth’s axis. Of the two, obliquity is the major factor, with eccentricity playing a minor but measurable role. And remember, we move slightly faster in our orbit in January near perihelion as per Kepler’s Laws of planetary motion than at aphelion, which occurred earlier this month , though be careful not to confuse the term “faster” with “sun fast.”

This means that were the Earth to orbit the Sun in a perfect circle with its poles perpendicular to its orbit, apparent and mean time would essentially stay in sync. Of course, no known planet has such a perfect alignment scenario, and other worlds do indeed host alien analemmas (analemmae?) of their own.

It’s also interesting to note that the two each major and minor minima of the Equation of Time roughly coincide with the four cross quarter tie in days of the year (marked by Groundhog’s Day, May Day, Lammas Day and Halloween, respectively) while the zero value points fall within a few weeks of the equinoxes and solstices.

A graph showing the flucuation of the value of the Equation of Time throughout the callendar year. (Created by the author).
A graph showing the fluctuation of the value of the Equation of Time (with minutes on the vertical axis) throughout the calendar year. (Created by the author).

In the current epoch, the deep minimum falls on February 21st, while the highest maximum falls on November 3rd on non-leap years. The four zero value dates are April 15th, June 13th, September 1st and December 25th respectively. The exact timing of these also slip to the tune of about a second a year, but of course, most sundials lack this sort of precision.

A "globe sundial" on the University of North Dakota at grand Forks campus. (Photo by author).
A “globe sundial” on the University of North Dakota at Grand Forks campus. (Photo by author).

So, why should we care about the Equation of Time in the modern atomic clock age? It is true that there have been calls over the past few years to “abolish the leap second” and go off of the astronomical time standard entirely… if this ever does come to pass, some future Pope Gregory will have to institute a “leap hour” circa 10,000 A.D. or so to stop the Sun from rising at 2 AM. But some modern day Sun tracking devices (think heliostats or solar panels) do in fact use mechanical timers and must take the equation of time into account to maximize effectiveness.

You can plot your very own simulated analemma using a desktop planetarium program. (Credit: Starry Night Education software).
Impatient? You can plot your very own simulated analemma using a desktop planetarium program. (Credit: Starry Night Education software).

Want to see the Equation of Time in action? You can make your own analemma simply by photographing the position of the Sun at the same time each day. Just remember to account for the shift on and off of Daylight Saving if you live in an area that observes the archaic practice, residents of Arizona need not to take heed. Otherwise, you’ll end up with a “split analemma…” Wintertime near the December Solstice is the best time to start this project, as the Sun is at its lowest noonday culmination and this will assure that your very own personal analemma won’t fall below the local horizon.

Farther afield, the effects of the Precession of the Equinoxes will also tweak the dates of the Equation of Time values a bit. Live out a full 72 year life span, and the equinoctial points will have drifted along the ecliptic by about one degree, twice the diameter of the Full Moon. Incidentally, the failure to take Precession into account is yet another spectacular fail of modern astrology: most “houses” or “signs” have drifted in the past millennia to the point where most “Leos” are in fact “Cancers!”

Such is the challenges and vagaries of modern day astronomical time-keeping. Let us know of your tales of tragedy and triumph as you hunt down the elusive analemma.

Stunning Amateur Timelapse of Jupiter ‘Re-enacts’ Voyager Flyby

This animated gif shows Voyager 1's approach to Jupiter during a period of over 60 Jupiter days in 1979. Credit: NASA.

Back in the 1970’s when NASA launched the two Voyager spacecraft to Jupiter, Saturn, Uranus, and Neptune, I remember being mesmerized by a movie created from Voyager 1 images of the movement of the clouds in Jupiter’s atmosphere. Voyager 1 began taking pictures of Jupiter as it approached the planet in January 1979 and completed its Jupiter encounter in early April. During that time it took almost 19,000 pictures and many other scientific measurements to create the short movie, which you can see below, showing the intricate movement of the bright band of clouds for the first time.

Now, 35 years later a group of seven Swedish amateur astronomers achieved their goal of replicating the Voyager 1 footage, not with another flyby but with images taken with their own ground-based telescopes.

“We started this joint project back in December of 2013 to redo the NASA Voyager 1 flyby of Jupiter,” amatuer astronomer Göran Strand told Universe Today. “During 90 days we captured 560 still images of Jupiter and turned them into 90 complete maps that covered the whole of Jupiter’s surface.”

Their newly released film, above details the work they did and the hurdles they overcame (including incredibly bad weather in Sweden this winter) to make their dream a reality. They called their project “Voyager 3.”

Animated gif of the 'Voyager 3' team re-enactment of the Voyager 1 flyby. Credit: Voyager 3 team, via Kristoffer Åberg.
Animated gif of the ‘Voyager 3’ team re-enactment of the Voyager 1 flyby. Credit: Voyager 3 team, via Kristoffer Åberg.
It is really an astonishing project and those of you who do image processing will appreciate the info in the video about the tools they used and how they did their processing to create this video.

The seven Swedish astronomers who participated in the Voyager 3 project are (from left to right in the photo below) Daniel Sundström, Torbjörn Holmqvist, Peter Rosén (the project initiator), Göran Strand, Johan Warell and his daughter Noomi, Martin Högberg and Roger Utas.

The Swedish team of amateur astronomers who compiled the 'Voyager 3' project. Image courtesy Peter Rosén.
The Swedish team of amateur astronomers who compiled the ‘Voyager 3’ project. Image courtesy Peter Rosén.

Congrats to the team of Voyager 3!

You can read more about the Voyagers visits to Jupiter here from NASA.

Voyager3Movie from Peter Rosén on Vimeo.

An Astronomical Eloping: How Rare is a “Friday the 13th Honey Moon?”

The June 2012 "Honey Moon" rising. Photo credit: Stephen Rahn.

Ah, Friday the 13th. Whether you fear it or it’s just your favorite slasher flick, it’s coming right around the bend later this week. And while it’s pretty much a non-event as far as astronomy is concerned, there’s bound to be some woo in the works, because the June Full Moon — dubbed the “Honey Moon” — falls on the same date.

Well, sort of. We made mention of this month’s Full Moon falling on Friday the 13th in last week’s post on the occultation of Saturn by Earth’s Moon. We’re not out to alarm any triskaidekaphobics, but we always love the chance to have some fun with calendars in the name of astronomy.

What we’re seeing here is merely the intersection of three cycles of events… and nothing more. These sorts of things can be fun to calculate and can provide a teachable moment, even when that well meaning but often misinformed relative/coworker/stranger on Twitter sends it your way . Hey, some people golf or collect steel pennies, this is our shtick.

A “Friday the 13th Honey Moon” is basically the subset of: 1. Fridays that fall on the 13th day of the month (OK, that’s two input parameters, we know) that also 2. Fall in the month of June, and 3. Occur on a Full Moon.

Friday the 13th occurs from one to three times a calendar year, so you can already see that one will occasionally happen to land on a Full Moon date fairly frequently… but how ‘bout in June? To this end, we compiled this handy listing of “Full Moons that fall on the 13th day of the month” — 15 in all — that occur from 1990 to 2030:

Full Moon's that fell on the 13th from 1990-2030 as reckoned in Universal Time. Only one (March 1998) fell on a Friday the 13th. Chart by author.
Full Moons that fell on the 13th from 1990-2030 as reckoned in Universal Time. Only two (March 1998 and June 2014) fall on a Friday the 13th. Chart by author.

That’s about one every two to three years. But you have to go aaaaall the way back to June 13th, 1919 to find a Full Moon that fell on a Friday the 13th in the month of June. This will next occur on June 13th, 2098.

Of course, this is just an interesting intersection concerning the vagaries and nuances of our Gregorian calendar and the lunar cycle. You could just as easily see significance where there is none in the Full Moon coinciding with the next Superbowl or Academy Awards. Humans love to pick out patterns where often none exist.

(Fun homework assignment: When is the last/next total lunar eclipse that occurs on Friday the 13th?)

And keep in mind, the instant of the Full Moon this week occurs on Friday at 4:13 UT… this means that from the U.S. Central time zone westward, the Full Moon actually falls on Thursday the 12th.

The rising Moon just hours before Full on Thursday June 12th. Note Saturn to the upper right. Created using Stellarium.
The rising Moon just hours before Full on Thursday June 12th. Note Saturn to the upper right. Created using Stellarium.

Fun fact: the 13th falls on a Friday more than any other day of the month! It’s true… in a span of 400 years following the institution of the Gregorian calendar in 1582, Friday fell on the 13th a total of 688 times, while Thursday and Saturday the 13th fell in last place at 684.

But there’s is something else that’s special about the June Full Moon. It also falls closest to the June solstice, marking the start of astronomical northern hemisphere summer and winter in the southern. This means that the Full Moon nearest the June solstice rides at its lowest to the southern horizon for northern hemisphere observers, but is high in the sky for observers south of the equator.

The June 2012 Full Honey (or do you say Strawberry?) Moon.
The June 2012 Full Honey (or do you say Strawberry?) Moon. Photo by author.

The June solstice this year falls on Saturday, June 21st at 10:51 UT /6:51 AM EDT. The Full Moon closest to the June solstice is nearly, but not always, in June… It can occur up to July 6th, and the last time it fell in July is 2012 and the next is 2015. The July Full Moon is known as the Full Buck Moon.

Our good friends over at Slooh will be webcasting the Full Honey Moon this Friday the starting at 1:30 UT/9:30 PM EDT (Thursday June 12th) for two hours from its Canary Islands site and the Pontificia Universidad Católica de Chile observatory near Santiago, Chile. The broadcast will be hosted by Slooh astronomer Geoff Fox, astronomer and author of The Sun’s Heartbeat Bob Berman, and Slooh engineer Paul Cox.

Is there a connection between late spring weddings, the June Full Moon and the modern term “honeymoon”? Well, the rising June Full Moon certainly takes on an amber color for northern hemisphere observers as it rises low through the sultry summer skies. The Moon’s orbit is actually tilted five degrees relative to the ecliptic, which means it alternates from “flat” to “hilly” about every 9 years varying from 18 to 28 degrees relative to the celestial equator. We’re approaching a flat year — known as minimum or minor lunar standstill — in 2015, after which the Moon’s apparent path across the sky will begin to widen once again towards 2024.

Credit Wikimedia Commons graphic in the Public Domain.
The ~9 year variation between major and minor lunar standstill. Credit Wikimedia Commons graphic in the Public Domain.

Bob Berman has this to say about the origin of the term: “Is this Full Moon of June the true origin of the word honeymoon, since it is amber, and since weddings were traditionally held this month? That phrase dates back nearly half a millennium to 1552, but one thing has changed: weddings have shifted, and are now most often held in August or September. The idea back then was that a marriage is like the phases of the Moon, with the Full Moon being analogous to a wedding. Meaning, it’s the happiest and ‘brightest’ time in a relationship.”

It’s also worth noting the June Full Moon was known as the Strawberry Moon to the Algonquin Indians of North America. Huh… and here we thought most weddings were in May.

Whatever the case, you can get out enjoy the rising Full Moon with that significant other this week… and don’t fear the Honey Moon.

Discovered: Two New Planets for Kapteyn’s Star

An artist's conception of the planets orbiting Kapteyn's Star (inset) and the stream of stars associated with an ancient galaxy merger. Credit: image courtesy of Victor Robles, James Bullock, and Miguel Rocha at University of California Irvine and Joel Primack at University of California Santa Cruz.

The exoplanet discoveries have been coming fast and furious this week, as astronomers announced a new set of curious worlds this past Monday at the ongoing American Astronomical Society’s 224th Meeting being held in Boston, Massachusetts.

Now, chalk up two more worlds for a famous red dwarf star in our own galactic neck of the woods. An international team of astronomers including five researchers from the Carnegie Institution announced the discovery this week of two exoplanets orbiting Kapteyn’s Star, about 13 light years distant. The discovery was made utilizing data from the HIRES spectrometer at the Keck Observatory in Hawaii, as well as the Planet Finding Spectrometer at the Magellan/Las Campanas Observatory and the European Southern Observatory’s La Silla facility, both located in Chile.

The Carnegie Institution astronomers involved in the discovery were Pamela Arriagada, Ian Thompson, Jeff Crane, Steve Shectman, and Paul Butler. The planets were discerned using radial velocity measurements, a planet-hunting technique which looks for tiny periodic changes in the motion of a star caused by the gravitational tugging of an unseen companion.

“That we can make such precise measurements of such subtle effects is a real technological marvel,” said Jeff Crane of the Carnegie Observatories.

Kapteyn’s Star (pronounced Kapt-I-ne’s Star) was discovered by Dutch astronomer Jacobus Kapteyn during a photographic survey of the southern hemisphere sky in 1898. At the time, it had the highest proper motion of any star known at over 8” arc seconds a year — Kapteyn’s Star moves the diameter of a Full Moon across the sky every 225 years — and held this distinction until the discovery of Barnard’s Star in 1916. About a third the mass of our Sun, Kapteyn’s Star is an M-type red dwarf and is the closest halo star to our own solar system. Such stars are thought to be remnants of an ancient elliptical galaxy that was shredded and subsequently absorbed by our own Milky Way galaxy early on in its history. Its high relative velocity and retrograde orbit identify Kapteyn’s Star as a member of a remnant moving group of stars, the core of which may have been the glorious Omega Centauri star cluster.

The worlds of Kapteyn’s Star are proving to be curious in their own right as well.

“We were surprised to find planets orbiting Kapteyn’s Star,” said lead author Dr. Guillem Anglada-Escude, a former Carnegie post-doc now with the Queen Mary University at London. “Previous data showed some irregular motion, so we were looking for very short period planets when the new signals showed up loud and clear.”

The location of Kapteyn's Star in teh constellation Pictor. Created using Stellarium.
The location of Kapteyn’s Star in the constellation Pictor. Created using Stellarium.

It’s curious that nearby stars such as Kapteyn’s, Teegarden’s and Barnard’s star, though the site of many early controversial claims of exoplanets pre-1990’s, have never joined the ranks of known worlds which currently sits at 1,794 and counting until the discoveries of Kapteyn B and C. Kapteyn’s star is the 25th closest to our own and is located in the southern constellation Pictor. And if the name sounds familiar, that’s because it made our recent list of red dwarf stars for backyard telescopes. Shining at magnitude +8.9, Kapteyn’s star is visible from latitude 40 degrees north southward.

Kapteyn B and C are both suspected to be rocky super-Earths, at a minimum mass of 4.5 and 7 times that of Earth respectively. Kapteyn B orbits its primary once every 48.6 days at 0.168 A.U.s distant (about 40% of Mercury’s distance from our Sun) and Kapteyn C orbits once every 122 days at 0.3 A.U.s distant.

This is really intriguing, as Kapteyn B sits in the habitable zone of its host star. Though cooler than our Sun, the habitable zone of a red dwarf sits much closer in than what we enjoy in our own solar system. And although such worlds may have to contend with world-sterilizing flares, recent studies suggest that atmospheric convection coupled with tidal locking may allow for liquid water to exist on such worlds inside the “snow line”.

And add to this the fact that Kapteyn’s Star is estimated to be 11.5 billion years old, compared with the age of the universe at 13.7 billion years and our own Sun at 4.6 billion years. Miserly red dwarfs measure their future life spans in the trillions of years, far older than the present age of the universe.

A comparison of habitable zones of Sol-like versus Red dwarf stars. Credit: Chewie/Ignacio Javier under a Wikimedia Commons 3.0 license).
A comparison of habitable zones of Sol-like versus red dwarf stars. Credit: Chewie/Ignacio Javier under a Wikimedia Commons 3.0 license).

“Finding a stable planetary system with a potentially habitable planet orbiting one of the very nearest stars in the sky is mind blowing,” said second author and Carnegie postdoctoral researcher Pamela Arriagada. “This is one more piece of evidence that nearly all stars have planets, and that potentially habitable planets in our galaxy are as common as grains of sand on the beach.”

Of course, radial velocity measurements only give you lower mass constraints, as we don’t know the inclination of the orbits of the planets with respect to our line of sight. Still, this exciting discovery could potentially rank as the oldest habitable super-Earth yet discovered, and would make a great follow-up target for the direct imaging efforts or the TESS space telescope set to launch in 2017.

“It does make you wonder what kind of life could have evolved on those planets over such a long time,” added Dr Anglada-Escude. And certainly, the worlds of Kapteyn’s Star have had a much longer span of time for evolution to have taken hold than Earth… an exciting prospect, indeed!

-Read author Alastair Reynolds’ short science fiction piece Sad Kapteyn accompanying this week’s announcement.

This Was the Best Watched Solar Flare Ever

X1-class solar flare on March 29, 2014 as seen by NASA's IRIS (video screenshot) Some stars emit even stronger "superflares" similar to these, but much brighter. Credit: NASA/IRIS/SDO/Goddard Space Flight Center
X1-class solar flare on March 29, 2014 as seen by NASA's IRIS (video screenshot) Some stars emit even stronger "superflares" similar to these, but much brighter. Credit: NASA/IRIS/SDO/Goddard Space Flight Center

Are giant dragons flying out of the Sun? No, this is much more awesome than that: it’s an image of an X-class flare that erupted from active region 2017 on March 29, as seen by NASA’s Interface Region Imaging Spectrograph (IRIS) spacecraft. It was not only IRIS’s first view of such a powerful flare, but with four other solar observatories in space and on the ground watching at the same time it was the best-observed solar flare ever.

(But it does kind of look like a dragon. Or maybe a phoenix. Ah, pareidolia!)

Check out a video from NASA’s Goddard Space Flight Center below:

In addition to IRIS, the March 29 flare was observed by NASA’s Solar Dynamics Observatory (SDO), NASA’s Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), JAXA and NASA’s Hinode spacecraft, and the National Solar Observatory’s Dunn Solar Telescope in New Mexico.

With each telescope equipped with instruments specially designed to observe the Sun in specific wavelengths almost no detail of this particular flare went unnoticed, giving scientists comprehensive data on the complex behavior of a single solar eruption.

Also, for another look at this flare from SDO and a coronal dimming event apparently associated with it, check out Dean Pesnell’s entry on the SDO is GO! blog here.

Source: NASA/GSFC

Watch: New Documentary Follows the Hunt for Gravitational Waves

A newly released documentary brings you behind the scenes in the hunt for gravitational waves. The 20-minute film, called “LIGO, A Passion for Understanding,” follows the scientists working to create one of the most powerful scientific tools ever made: the Laser Interferometer Gravitational-Wave Observatories (LIGO). You can watch the documentary above.
Continue reading “Watch: New Documentary Follows the Hunt for Gravitational Waves”

The Search for Gravitational Waves: New Documentary About LIGO Premieres Soon

Laser Interferometer Gravitational-Wave Observatory Hanford installation - each arm extends for four kilometres. Credit: Caltech.

What happens when stars or black holes collide? Scientists have theorized that the energy released would disturb the very fabric of the space-time continuum, much like ripples in a pond. These ripples are called gravitational waves, and while proving the existence of these waves has been difficult, their detection would open a brand new window on our understanding of the Universe.

The Laser Interferometer Gravitational-wave Observatories (LIGO) have been searching for these elusive waves. A new documentary about LIGO will be available soon here on Universe Today, and it documents the science and people behind the unprecedented astronomical tool designed to catch sight of violent cosmic events trillions of miles from our planet.

The new documentary titled, “LIGO, A Passion for Understanding,” follows scientists working with LIGO. It is produced by filmmaker Kai Staats, and this will actually be the first installment to a multi-video series, in fact. Watch the trailer, above.

“A Passion for Understanding” brings to life one of the most important astronomical tools of our time while telling the human story of creativity, passion, and drive to understand the very fabric of the Universe in which we live.
Operated by teams from the California Institute of Technology and Massachusetts Institute of Technology, LIGO’s observatories use 4 km laser beams to hunt for gravitational waves. The LIGO scientific collaboration consists of hundreds of scientists from around the world.

LIGO’s enhanced run ended in 2010, but the Advanced LIGO project featuring newly upgraded instruments is set to begin its run in late 2015. Advanced LIGO will probe deeper into the universe in search of gravitational waves.

Find out more about the documentary on the film’s Facebook page, at the LIGO collaboration website, and on Space.com.

LIGO, A Passion for Understanding – Trailer from Kai Staats on Vimeo.