History Archives

September 2, 2014December 23, 2015 by David Dickinson

Hunting for “Minimoons” Orbiting Earth

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.

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 21^st 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.”

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.

August 28, 2014December 23, 2015 by David Dickinson

Observing Neptune: A Guide to the 2014 Opposition Season

Never seen Neptune? Now is a good time to try, as the outermost ice giant world reaches opposition this weekend at 14:00 Universal Time (UT) or 10:00 AM EDT on Friday, August 29^th. This means that the distant world lies “opposite” to the Sun as seen from our Earthly perspective and rises to the east as the Sun sets to the west, riding high in the sky across the local meridian near midnight.

2014 finds Neptune shining at magnitude +7.6 in the constellation of Aquarius. Unfortunately, the planet is too faint to be seen with the naked eye, but can be sighted using a good pair of binoculars if know exactly where to look for it. Though the telescope, Neptune exhibits a tiny blue-gray disk 2.4” across — 750 “Neptunes” would fit across the apparent diameter of the Full Moon — that’s barely discernible. Don’t be afraid to crank up the magnification in your quest. We’ve found Neptune on years previous by patently examining suspect stars one by one, looking for the one in the field that stubbornly refuses to focus to a star-like point. Make sure your optics are well collimated to attempt this trick. Neptune will exhibit a tiny fuzzy disk, much like a second-rate planetary nebula. In fact, this is where “planetaries” get their moniker, as the pesky deep sky objects resembled planets in those telescopes of yore…

Looking eastward — The position of Neptune, looking eastward on the night of opposition around an hour after sunset. Created using Stellarium.

The 1846 discovery of Neptune stood as a vindication of the (then) new-fangled theory of Newtonian gravitational dynamics. Uranus was discovered just decades before by Sir William Hershel in 1781, and it stubbornly refused to follow predictions concerning its position. French astronomer Urbain Le Verrier correctly assumed that an unseen body was tugging on Uranus, predicted the position of the suspect object in the sky, and the race was on. On the night of September 24th, Heinrich Louis d’Arrest and Johann Gottfried Galle observing from the Berlin observatory became the first humans to gaze upon the new world referring to it as such. Did you know: Galileo actually sketched Neptune near Jupiter in 1612? And those early 18^th century astronomers got a lucky break… had Neptune happened to have been opposite to Uranus in its orbit, it might’ve eluded discovery for decades to come!

It’s also sobering to think that Neptune has only recently completed a single orbit of the Sun in 2011 since its discovery. Opposition of Neptune occurs once every 368 days, meaning that opposition is slowly moving forward by about three days a year on our Gregorian calendar and will soon start occurring in northern hemisphere Fall.

Neptune and a one degree field (green) circle. Note that it passes the bright naked eye star Sigma Aquarii on September 15th. Created using Starry Night Education Software.

Now for the “wow factor” of what you’re actually seeing. Though tiny, Neptune is actually 24,622 kilometres in radius, and is 58 times as big as the Earth in volume and over 17 times as massive. Neptune is 29 A.U.s or 4.3 billion kilometres from Earth at opposition, meaning the light we see took almost four hours to transit from Neptune to your backyard.

Neptune is currently south of the equator, and won’t be north of it again until 2027.

Next month, keep an eye on Neptune as it passes less than half a degree north of the +4.8 magnitude star Sigma Aquarii through mid-September, making a great guide to find the planet…

Aug 29 — The orbit of Triton on the evening of August 29th, superimposed on a one arc minute field of view. Created using Starry Night Software.

Still not enough of a challenge? Try tracking down Neptune’s large moon, Triton. Orbiting the planet in a retrograde path once every 5.9 days, Triton is within reach of a large backyard scope at magnitude +14. Triton never strays more than 15” from the disk of Neptune, but opposition is a great time to cross this curious moon off of your observing life list. Neptune has 14 moons at last count.

And speaking of Triton, NASA recently released a new map of the moon. We’ve only gotten one good look at Triton, Neptune, and its retinue of moons back in 1989 when Voyager 2 conducted the only flyby of the planet to date. Will Pluto turn out to be Triton’s twin when New Horizons completes its historic flyby next summer?

The Moon also passes 4.3 degrees north of Neptune on September 8th on its way to “Supermoon 3 of 3” for 2014 on the night of September 8^th/9th. Fun fact: a cycle of occultations of Neptune by the Moon commences on June 2016.

When will we explore Neptune once more? Will a dedicated “Neptune orbiter” ever make its way to the planet in our lifetimes? All fun things to ponder as you check out the first planet discovered using scientific reasoning this weekend.

August 25, 2014December 23, 2015 by David Dickinson

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

“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.”

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.

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!

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.

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.

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.

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 8^th 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 21^st, 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.

August 20, 2014December 23, 2015 by David Dickinson

Remembering the “World War I Eclipse”

The paths of total solar eclipses care not for political borders or conflicts, often crossing over war-torn lands.

Such was the case a century ago this week on August 21^st, 1914 when a total solar eclipse crossed over Eastern Europe shortly after the outbreak of World War I.

Known as the “War to End All Wars,” — which, of course, it didn’t — World War I would introduce humanity to the horrors of modern warfare, including the introduction of armored tanks, aerial bombing and poison gas. And then there was the terror of trench warfare, with Allied and Central Powers slugging it out for years with little gain.

But ironically, the same early 20^th century science that was hard at work producing mustard gas and a better machine gun was also pushing back the bounds of astronomy. Einstein’s Annus Mirabilis or “miracle year” occurred less than a decade earlier on 1905. And just a decade later in 1924, Edwin Hubble would expand our universe a million-fold with the revelation that “spiral nebulae” were in fact, island universes or galaxies in their own right.

Indeed, it’s tough to imagine that many of these discoveries are less than a century in our past. It was against this backdrop that the total solar eclipse of August 21^st, 1914 crossed the eastern European front embroiled in conflict.

Solar eclipses have graced the field of battle before. An annular solar eclipse occurred during the Battle of Isandlwana in 1879 during the Zulu Wars, and a total solar eclipse in 585 B.C. during the Battle of Thales actually stopped the fighting between the Lydians and the Medes.

A photograph of an “eclipse camp” in the Crimea in 1914. Credit: University of Cambridge DSpace.

But unfortunately, no celestial spectacle, however grand, would save Europe from the conflagration war. In fact, several British eclipse expeditions were already en route to parts of Russia, the Baltic, and Crimea when the war broke out less than two months prior to the eclipse with the assassination of Archduke Ferdinand on June 28^th, 1914. Teams arrived to a Russia already mobilized for war, and Britain followed suit on August 4^th, 1914 and entered the war when Germany invaded Belgium.

You can see an ominous depiction of the path of totality from a newspaper of the day, provided from the collection of Michael Zeiler:

1914_August_22_TSE_The_Graphic_1 — An illustration of the 1914 total solar eclipse “scorching” a war-ravaged Europe. Credit: From the collection of Michael Zeiler. Used with permission.

Note that the graphic depicts a Europe aflame and adds in the foreboding description of Omen faustum, inferring that the eclipse might be an “auspicious omen…” eclipses have never shaken their superstitious trappings in the eyes of man, which persists even with today’s fears of a “Blood Moon.”

A race was also afoot against the wartime backdrop to get an expedition to a solar eclipse to prove or disprove Einstein’s newly minted theory of general relativity. One testable prediction of this theory is that gravity bends light, and astronomers soon realized that the best time to catch this in action would be to measure the position of a star near the limb of the Sun — the most massive light bending object in our solar system — during a total solar eclipse. The advent of World War I would scrub attempts to observe this effect during the 1914 and 1916 eclipses over Europe.

An expedition led by astronomer Arthur Eddington to observe an eclipse from the island of Principe off of the western coast of Africa in 1919 declared success in observing this tiny deflection, measuring in less than two seconds of arc. And it was thus that a British expedition vindicated a German physicist in the aftermath of the most destructive war up to that date.

The total solar eclipse of August 21^st 1914 was a member of saros cycle 124, and was eclipse number 49 of 73 in that particular series. Eclipses in the same saros come back around to nearly the same circumstances once every triple saros period of 3 times 18 years and 11.3 days, or about every 54+ years, and there was an eclipse with similar circumstances slightly east of the 1914 eclipse in 1968 — the last total eclipse of saros 124 — and a partial eclipse from the same saros will occur again on October 25^th, 2022.

All historical evidence we’ve been able to track down suggests that observers that did make it into the path of totality were clouded out at show time, or at very least, no images of the August 21^st 1914 eclipse exist today. Can any astute reader prove us wrong? We’d love to see some images of this historical eclipse unearthed!

A simulation of the total solar eclipse of August 21st 1914 as seen from Latvia. Created using Starry Night Education software.

And, as with all things eclipse related, the biggest question is always: when’s the next one? Well, we’ve got another of total lunar eclipse coming right up on October 8^th, 2014, again favoring North America. The next total solar eclipse occurs on March 20^th, 2015 but is only visible along a path covering the Faroe and Svalbard Islands, with a path crossing the Norwegian Sea.

But, by happy coincidence, we’re also only now three years out this week from the total solar eclipse of August 21^st, 2017 that spans the contiguous “Lower 48” of the United States. The shadow of the Moon will race from the northwest and make landfall off of the Pacific coast of Oregon before reaching a maximum duration for totality at 2 minutes and 40 seconds across Missouri, southern Illinois and Kentucky and will then head towards the southeastern U.S. to depart land off of the coast of South Carolina. Millions will witness this event, and it will be the first total solar eclipse for many. A total solar eclipse hasn’t crossed the contiguous United States since 1979, so you could say that we’re “due”!

Already, towns in Kentucky to Nebraska have laid plans to host this event. The eclipse occurs towards the afternoon for residents of the eastern U.S., which typically sees afternoon thunderstorms popping up in the sultry August summer heat. Eclipse cartographer Michael Zeiler states that the best strategy for eclipse chasers three years hence is to “go west, young man…”

It’s fascinating to ponder tales of eclipses past, present, and future and the role that they play in human history… where will you be on August 21^st, 2017?

– Check out Michael Zeiler’s new site, GreatAmericanEclipse.com

– Eclipses pop up in science fiction on occasion as well… check out our history spanning eclipse tale Exeligmos.

July 7, 2014December 23, 2015 by Nancy Atkinson

Buzz Aldrin Wants to Know: Where Were You When Apollo 11 Landed on the Moon?

Neil Armstrong and Buzz Aldrin plant the US flag on the Lunar Surface during 1st human moonwalk in history 45 years ago on July 20, 1969 during Apollo 1l mission. Credit: NASA

If you are 45 years or older, chances are you know where you were and what you were doing on July 20th, 1969 when Apollo 11 landed on the Moon. Apollo 11 lunar module pilot Buzz Aldrin says that when he travels around the world, people always want to tell him their stories from that day when he and Neil Armstrong walked on the Moon. And he says he actually likes to hear all these stories because he and his crewmates missed all the hubbub back on Earth, since they were decidedly off making history.

And now you can tell Buzz your story own story about Apollo 11, and share it with the world, as well. To celebrate the upcoming 45th anniversary of the Apollo 11 Moon landing, Buzz has just launched a social media campaign where you can share your story, your parents’, your grandparents’, or your friends’ stories of that moment and how it inspired you.

“I feel we need to remind people about our Apollo missions and that we can still do impossible things,” Buzz says in this new video, above.

You can tell your story on social media, using the hashtag #Apollo45, or visit the Apollo45 You Tube Channel where you can post a video of your recollections. Videos will be shared from the public as well as featured videos from astronauts, public figures and celebrities.

This can be a family and/or generational project. As Buzz says, “Kids, help your parents if they don’t know how to use their smartphones. Get them to tell you their memories.”

We’d also like to see your stories here on Universe Today. Post in the comment section below and if you create a video, post the link.

I’ll start with my story:

I was quite young, but I do remember sitting on the floor with my sister in front of the television set, basically glued there since we didn’t want to miss a thing. We felt really lucky because our parents let us stay up late to watch the first moonwalk. Later, my Mom got me a T-shirt that had an eagle (bird) landing on the Moon with an Apollo 11 mission patch and the date “July 20, 1969” emblazoned on it, and I basically wore it non-stop.

Hat tip to Leonard David for letting us know about #Apollo45!

June 4, 2014December 23, 2015 by David Dickinson

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.

May 29, 2014December 23, 2015 by David Dickinson

Will an Asteroid Smack Jupiter in 2022?

PHA asteroid 2014 KM4 on approach to Jupiter in late 2021. Credit: the Solar System Dynamics JPL Small-Body Database Browser.

A recent space rock discovery has sent a minor buzz through the community that tracks such objects. And as usual, it has also begun to attract the dubious attention of those less than honorable sites — we won’t dignify them with links — that like to trumpet gloom and doom, and we thought we’d set the record straight, or at very least, head the Woo off at the pass as quickly as possible.

The asteroid in question is 2014 KM4. Discovered earlier this month, this 192 metre space rock safely passed by the Earth-Moon system at 0.17 A.U.s distant on April 21^st. No real biggie, as asteroids pass lots closer all the time. For example, we just had a 6-metre asteroid named 2014 KC45 pass about 48,000 miles (about 80,000 kilometres) from the Earth yesterday morning. That’s about twice the distance of the orbit of geosynchronous satellites and 20% the distance to the Moon.

Sure, it’s a dangerous universe out there… you only have to stand in the Barringer Meteor Crater in Arizona outside of Flagstaff or watch the videos of a meteor exploding over Chelyabinsk last year the day after Valentine’s Day to know that. But what makes 2014 KM4 interesting is its orbit and its potential to approach Jupiter in about seven years.

Or not. One dilemma with orbital mechanics is that the precision of a known orbital path relies on the number of observations made and that position gets more and more uncertain as we project an object’s position ahead in space and time. 2014 KM4 is on a 5.08 year orbit inclined 5.2 degrees to the ecliptic plane that brings it juuusst inside the Earth’s orbit — hence the Apollo designation — and out to an aphelion point very near Jupiter at 5.2 A.U.s from the Sun. But that’s only based on 14 observations made over a span of 5 days. The current nominal trajectory sees 2014 KM4 pass about 0.1 A.U. or 15.5 million kilometres from Jupiter on January 16^th 2022. That’s inside the orbit of Jupiter’s outermost moons, but comfortably outside of the orbit of the Galilean moons. The current chance of 2014 KM4 actually impacting Jupiter sits at around 1% and the general trend for these kinds of measurements is for the probability to go down as better observations are made. This is just what happened last year when comet 2013 A1 Siding Spring was discovered to pass very close to Mars later this year on October 19th.

We caught up with JPL astronomer Amy Mainzer, Principal Investigator on the NEOWISE project currently hunting for Near Earth Asteroids for her thoughts on the subject.

“The uncertainty in this object’s orbit is huge since it only has a 5 day observational arc,” Mainzer told Universe Today. “A quick check of the JPL NEO orbit page shows that the uncertainty in its semi-major axis is a whopping 0.47 astronomical units! That’s a huge uncertainty.”

“At this point, any possibility of impact with Jupiter is highly uncertain and probably not likely to happen. But it does point out why it’s so important to extend observational arcs out so that we can extend the arc far enough out so that future observers can nab an object when it makes its next appearance.”

Jupiter takes a beating from Comet Shoemaker-Levy 9. Credit: NASA/Hubble Space Telescope team.

IF (that less than 1% “IF”) 2014 KM4 were to hit Jupiter, it would represent the most distant projection ahead in time of such an event. About two decades ago, humanity had a front row seat to the impact of comet Shoemaker-Levy 9 into Jupiter in July 1994. At an estimated 192 metres in size, 2014 KM4 is about the size of the “D” fragment that hit Jupiter on July 17^th 1994. 2014 KM4 has an absolute magnitude (for asteroids, this is how bright they’d appear at 1 A.U. distant) of +21.3 and is currently well placed for follow up observations in the constellation Virgo.

And astronomer Nick Howes mentioned to Universe Today that the Faulkes Telescope North may soon be used to make further observations of 2014 KM4. In the meantime, you can enjoy the animation of their observations of another Near-Earth Asteroid, 2014 KP4.

An animation of the motion of PHA asteroid 2014 KP4. Credit: Remanzacco Observatory.

And yes, the 2022 pass of 2014 KM4 near Jupiter will modify the orbit of the asteroid… but not in our direction. Jupiter is a great “goal tender” in this regard, protecting the inner solar system from incoming hazards.

2014 KM4 is well worth keeping an eye on, but will most likely vanish from interest until it returns to our neck of the solar system in 2065. And no, a killer asteroid won’t hit the Earth in 2045, as a CNN iReport (since removed) stated earlier this week… on “March 35^th” no less. Pro-tip for all you conspiracy types out there that think “Big NASA” is secretly hiding the next “big one” from the public: when concocting the apocalypse, please refer to a calendar for a fictional date that at least actually exists!

April 23, 2014December 23, 2015 by David Dickinson

Saturn at Opposition: Our 2014 Guide

Saturn as imaged from Aguadilla, Puerto Rico on April 15th. Credit: Efrain Morales.

Planet lovers can rejoice: one of the finest jewels of the solar system in returning to the evening night sky.

The planet Saturn reaches opposition next month on May 10^th. This means that as the Sun sets to the west, Saturn will rise “opposite” to it in the east, remaining well positioned for observation in the early evening hours throughout the summer season. In fact, we’ll have four of the five naked eye planets above the horizon at once for our evening viewing pleasure in the month of May, as Jupiter also rides high to the west at sunset, Mars just passed opposition last month and Mercury reaches greatest eastern elongation on May 25^th. Venus is the solitary holdout, spending a majority of 2014 in the dawn sky.

Saturn will shine at magnitude +0.3 this month and its disk spans an apparent 19,” or 44” if you take into account the apparent width of its rings. The rings are currently tipped open 22 degrees with respect to our line of sight. The ring opening is widening, and will reach a maximum of over 25 degrees in 2017 before the trend reverses. Anyone who remembers observing Saturn back in 2009 will recall that its rings were edge on to our view. This widening of Saturn’s rings also lends itself to a curious effect: although we’re in a cycle of oppositions that are getting farther away — Saturn is 12.5 million kilometres or 0.083 Astronomical Units (A.U.s) more distant in 2014 than it was during opposition last year as it’s headed towards aphelion in 2018 — its widening rings are actually making it appear a bit brighter.

The path of Saturn through the constellation Libra from April through October 2014. Created using Starry Night Education Software.

This year’s opposition will find Saturn in the astronomical constellation of Libra, where it’ll spend most of 2014. Oppositions of the ringed planet are set to continue to “head south” until 2018, and won’t occur north of the celestial equator again until 2026. I remember when oppositions of Saturn returned to the constellation Virgo a few years back — where I had first looked at it with my 60mm Jason refractor as a teenager — and realizing that I had now been into observational astronomy for roughly one “Saturnian year.”

The ancients had little knowledge of how unique Saturn was. The faintest and slowest moving of the classical planets, even Galileo knew that something was up when he turned his first primitive telescope towards it. His sketches depict Saturn as something similar to a double handled coffee cup, a testament to how poor his view really was. It wouldn’t be until Christiaan Huygens in 1655 that the true nature of Saturn’s rings was deduced as a flat and separate feature from the disk.

At opposition, the disk of the planet casts a shadow straight back from our point of view. This vantage slowly changes as the planet moves towards eastern quadrature on August 9th and we get a glimpse slightly off to one side of the planet. After opposition, the shadow of the disk can again be seen casting back onto the rings.

An outstanding IPhone 4S capture of Saturn on April 20th, 2014. Credit: Andrew Symes, @FailedProtostar.

Another interesting phenomenon to watch out for near opposition is known as the Seeliger effect. Also sometimes referred to as the “opposition surge,” this sudden brightening of the disk and rings is a subtle effect, as the globe of Saturn and all of those tiny little ice crystals reach 100% illumination. This effect can be noted to the naked eye on successive nights around opposition, and will get more prominent towards 2017. Coherent-backscattering of light has also been proposed as a possible explanation of this phenomenon. Perhaps a video sequence capturing this effect is in order for skilled astro-imagers in 2014.

Through a small telescope, the first feature that becomes apparent is Saturn’s glorious system of rings. Crank up the magnification, and you’ll note a dark groove in the ring system. This is the Cassini Division, first described by Giovanni Cassini in 1675.

Here’s a challenge we came across some years back: can you see the disk of Saturn through the Cassini Division? Right around opposition is a good time to attempt this unusual feat of visual athletics.

A sample simulation depicting the orientation of Saturn's observable moons on the night of May 9th. Created using Starry Night Education software. — A sample simulation depicting the orientation of Saturn’s observable moons on the night of May 9th. Created using Starry Night Education software.

Saturn’s large moon Titan is an easy catch at magnitude +8 in a small telescope. Titan is the second largest moon in the solar system. Place it in a direct orbit about the Sun, and it would be considered a planet, no problem. 7 of Saturn’s 62 known moons are within reach of a small telescope. In addition to Titan, they are, with quoted magnitudes: Mimas (+13), Enceladus (+12), Tethys (+10), Rhea (+10), Dione (+11) and Iapetus. Iapetus is of special interest, as it brightens from +11.9 to magnitude +10.2 as it traces out its 79 day orbit. We always knew there was something unique about this moon, and NASA’s Cassini mission revealed the world to have two distinctly different hemispheres with vastly different albedos during its close 2007 flyby.

The close passage of the Full Moon near Saturn on May 14th. Created using Stellarium.

Also, be sure to check out Saturn on the night of May 14^th — just 4 nights after opposition — as the Full Moon sits less than a degree south of the ringed planet. Can you see both in the same telescopic field of view? Can you nab Saturn next to the rising daytime Moon low to the horizon just before local sunset? The Moon will actually occult (pass in front of) Saturn for viewers based in Australia and New Zealand on the 14^th. This is only one of 11 occultations — nearly one for each lunation — of Saturn by the Moon in 2014. Unfortunately, the best one for North America occurs in the daytime on August 31^st, though it too may be observable telescopically.

The foot print of the May 14th occultation of Saturn by the Moon. Credit: Occult 4.0. — The footprint of the May 14th occultation of Saturn by the Moon. Credit: Occult 4.0.

Finally, this evening apparition of the planet runs through northern hemisphere summer and fall until Saturn reaches solar conjunction on November 18th. So get those homemade planetcams out, send those pics in to Universe Today, and be sure to join in to the Virtual Star Party every Sunday Night… Saturn is sure to be featured!

April 22, 2014April 26, 2016 by David Dickinson

Remembering John Houbolt: the Man Who Gave Us Lunar Orbit Rendezvous

John Houbolt demonstrating Lunar Orbit Rendezvous circa 1962. Credit: NASA.

The space community lost a colossus of the of the Apollo era last week, when John Houbolt passed away last Tuesday just five days after his 95^th birthday.

Perhaps the name isn’t as familiar to many as Armstrong or Von Braun, but John Houbolt was a pivotal figure in getting us to the Moon.

Born in Altoona, Iowa on April 10^th, 1919, Houbolt spent most of his youth in Joliet, Illinois. He earned a Masters degree in Civil Engineering from the University of Illinois at Urbana-Champaign in 1942 and a PhD in Technical Sciences from ETH Zurich in Switzerland in 1957. But before that, he would become a member of the National Advisory Committee for Aeronautics (NACA) in 1942, an organization that would later become the National Aeronautics and Space Administration or NASA in 1958.

It was 1961 when Houbolt made what would be his most enduring mark on the space program. He was working as an engineer at the Langley Research Center, at a time when NASA and the United States seriously needed a win in the space race. The U.S.S.R. had enjoyed a long string of firsts, including first satellite in orbit (Sputnik 1, October 1957), first spacecraft to photograph the lunar farside (Luna 3 in October 1959) and first human in space with the launch of Yuri Gagarin aboard Vostok 1 in April 1961. A young President Kennedy would make his now famous “We choose to go to the Moon…” speech at Rice University later the next year in late 1962. Keep in mind, in U.S. astronaut John Glenn had just made his first orbital flight months before Kennedy’s speech, and total accumulated human time in space could be measured in mere hours. Unmanned Ranger spacecraft were having a tough time even getting off of the pad, and managing to crash a space probe into the Moon was considered to be a “success”. The task of sending humans “by the end of this decade” was a daunting one indeed…

NASA would soon have a mandate to sent humans to the Moon: but how could they pull it off?

Early ideas for manned lunar missions envisioned a single gigantic rocket that would head to the Moon and land, Buck Rodgers style, “fins first.” Such a rocket would have to be enormous, and carry the fuel to escape Earth’s gravity well, land and launch from the Moon, and return to Earth.

A second approach, known as Earth-orbit rendezvous, would see several launches assemble a mission in low Earth orbit and then head to the Moon. Curiously, though this was an early idea, it was never used in Apollo, though it was briefly resurrected during the now defunct Constellation Program.

Three plans to go to the Moon. Credit: NASA.

But it was a third option that intrigued Houbolt, known as Lunar Orbit Rendezvous. LOR had been proposed by rocket pioneers Yuri Kondratyuk and Hermann Oberth in 1923, but had never been seriously considered. It called for astronauts to depart the Earth in a large rocket, and instead, use a small lander designed only to land and launch from the Moon while the spacecraft for Earth return orbited overhead.

Houbolt became a staunch advocate for the idea, and spent over a year convincing NASA officials. In one famous letter to NASA associate administrator Robert Seamans, Houbolt was known to have remarked “Do we want to go to the Moon or not?”

It’s interesting to note that it was probably only in a young organization like the NASA of the early 1960s that, in Houbolt’s own words, a “voice in in the wilderness” could be heard. Had NASA become a military run organization — as many advocated for in the 1950s — a rigid chain of command could have meant that such brash ideas as Houbolt’s would have never seen the light of day. Thank scientists such as James Van Allen for promoting the idea of a civilian space program that we take for granted today.

Even then, selling LOR wasn’t easy. The idea looked preposterous: astronauts would have to learn how to undock and dock while orbiting a distant world, with no chance of rescue. There was no second chance, no backup option. Early plans called for an EVA for astronauts to enter the Lunar Module prior to descent which were later scrapped in favor of extracting it from atop the third stage and boarding internally before reaching the Moon.

Once Houbolt had sold key visionaries such as Wernher von Braun on the idea in late 1962, LOR became the way we would go to the Moon. And although Houbolt’s estimations of the mass required for the Lunar Module were off by a factor of three, the story is now the stuff of early Apollo era legend. You can see Houbolt (played by Reed Birney) and the tale of the LM and LOR in the From Earth to the Moon episode 5 entitled “Spider”.

Houbolt was awarded NASA’s medal for Exceptional Scientific Achievement in 1963, and he was in Mission Control When Apollo 11 touched down in the Sea of Tranquility.

He passed away in a Scarborough, Maine nursing home last Tuesday, and joins other unsung visionaries of the early space program such as Mary Sherman Morgan. It’s sad to think that we may soon live in a world where those who not only walked on the Moon, but those who also sent us and knew how to get there, are no longer with us.

Thanks, John… you gave us the Moon.

April 18, 2014December 23, 2015 by David Dickinson

Get Ready for the Lyrid Meteor Shower: Our Complete Guide for 2014

A composite of 33 Lyrid meteors captured by the UK Meteor Network cameras in 2012. Credit: @UKMeteorNetwork

The month of April doesn’t only see showers that bring May flowers: it also brings the first dependable meteor shower of the season. We’re talking about the Lyrid meteors, and although 2014 finds the circumstances for this meteor shower as less than favorable, there’s still good reason to get out this weekend and early next week to watch for this reliable shower.

The Lyrid meteor shower typically produces a maximum rate of 10-20 meteors per hour, although outbursts topping over a hundred per hour have been observed on occasion. The radiant, or the direction that the meteors seem to originate from, lies at right ascension 18 hours and 8 minutes and declination +32.9 degrees north. This is just about eight degrees to the southwest of the bright star Vega, which is the brightest star in the constellation of Lyra the Lyre, which also gives the Lyrids its name.

Fun fact: this radiant actually lies juuusst across the border of Lyra in the constellation of Hercules… technically, the “Lyrids” should be the “Herculids!” This is because the shower was identified and named in the 19th century before the International Astronomical Union officially adopted the modern layout we use for the constellations in 1922.

The rising Lyrid radiant, looking to the north east at 2AM local from latitude 30 degrees north. Created using Stellarium. — The rising Lyrid radiant, looking to the northeast at 2AM local from latitude 30 degrees north. Created using Stellarium.

The source of the Lyrids was tracked down in the late 1860s by mathematician Johann Gottfried Galle to Comet C/1861 G1 Thatcher, the path of which came within 0.02 Astronomical Units (A.U.s) of the Earth’s orbit on April 20^th, 1861, just six weeks before the comet reached perihelion. Comet G1 Thatcher is on a 415 year orbit and won’t return to the inner solar system until the late 23^rd century.

But we can enjoy the dust grains it left in its wake as they greet the Earth to burn up in its atmosphere every April. The activity of the Lyrids typically spans April 16^th to the 25^th, with a short 24 hour peak above a ZHR of 10 on April 22^nd-23^rd. Thus, like the short duration Quadrantids in January, timing is critical; if you happen to observe this shower before or after the peak, you may see nothing at all. This year, the key mornings will be Tuesday, April 22^nd, and Wednesday April 23^rd. The wide disparity of predictions for the exact arrival of the peak of the Lyrids, as quoted in differing sources speaks to just how poorly this meteor shower is understood. Scanning various reliable resources, we see times quoted from April 22^nd at 4:00 Universal Time (UT) from the American Meteor Society, to 17:00 UT on the same date for the Royal Canadian Astronomical Society, to April 23^rd at 17:45 UT from Guy Ottewell’s venerable 2014 Astronomical Calendar!

Definitely, more observations of this curious shower are needed.

The position of the Lyrid meteor shower radiant across the border in the constellation Hercules. (Credit Starry Night Education software).

Now for the bad news. This year finds the light-polluting Moon in nearly its worst location possible for a meteor shower. Remember this week’s total lunar eclipse? Well, the Moon is now waning gibbous and will reach last quarter phase at 7:52 UT/3:52 AM EDT on April 22^nd, and will thus be rising at local midnight and be high in the sky towards dawn. The Lyrid radiant rises at 9:00 PM this week for observers around 40 degrees north and rides highest at 6:00 AM local, about 45 minutes before sunrise.

Looking at the International Meteor Organization’s historical data, here’s what the Lyrids have done over the past few years:

2013- ZHR 22, Moon phase= 88% illuminated, waxing gibbous.

2012– ZHR 25, Moon phase= 2% illuminated, waxing crescent.

2011- ZHR 20, Moon phase= 73% illuminated waning gibbous.

2010- ZHR 32, Moon phase= 62% illuminated waxing gibbous.

2009- ZHR 15, Moon phase= 7% illuminated waning crescent.

A “ZHR” is the Zenithal Hourly Rate, a theoretical maximum number of meteors that an observer could expect to witness under dark skies if the radiant was straight overhead. Note that 2011 had similar circumstances with respect to the Moon as this year, so don’t despair! The Lyrids are approaching the Earth from nearly perpendicular in its orbit and have a head on velocity of about 48 kilometres per second, respectable for a meteor shower. They also present a higher-than-average number of fireballs, with about a quarter leaving persistent trains.

Outbursts have also occurred in 1803, 1849, 1850, 1922, 1945 and 1982. United States observers based in Florida and Colorado noted a brief ZHR approaching 100 per hour back in 1982 under especially favorable New Moon conditions.

The orientation of the Earth on April 22nd at 12UT/08AM EDT. Credit: Stellarium.

Ironically, the Lyrids are also one of the oldest meteor showers identified from historic records. In fact, Galle actually traced the shower back to Chinese records dating all the way back to March 16^th 687 BC, which describes “Stars (that) dropped down like rain…” clearly, the Lyrids were considerably more active in ancient times.

More recently, attempts were made to link the 2012 Sutter’s Mill meteorite fall to the Lyrids, which were underway at the time. This turned out to be a case of “meteor-wrong,” however, as described by Geoff Notkin of the Meteorite Men who noted that no meteorite fall has ever been linked to a meteor shower, though he does get lots of calls whenever news of a big meteor shower hits the press.

A good strategy for beating the Moon includes blocking it behind a hill or building while observing. Early morning is the best time to watch for Lyrids — or most any meteor shower for that matter — as you’re then on the half of the Earth facing forward into the meteor stream. And you don’t have to face toward the radiant to see Lyrid meteors, as they can appear anywhere in the sky.

With the advent of DSLRs, photographing meteors is easier than ever before. All you need to do is use a wide angle lens and take periodic time exposures of the sky. Do a few early test shots to get the combination of f-stop, ISO and shutter speed just right for current sky conditions, and be sure to review those images on a full size monitor afterward: nearly every meteor we’ve captured turned up in post-review only.

Looking to contribute to our understanding of the Lyrid meteors? Simply count the number you see and the location and length of your observation and send your report into the International Meteor Organization. And don’t forget to tweet those Lyrids to #Meteorwatch!

…and there’s more to come. Next month, a true “wildcard outburst” may be in the offing from Comet 209P/LINEAR on May 26^th… can you say “Camelopardalids?”

Stay tuned!