The Curious History of the Geminid Meteors

UPDATE: Tune in this Sunday as the good folks over at the Virtual Telescope Project feature a live webcast covering the Geminid meteor shower this Sunday on December 14th at 2:00 UT.

This weekend presents a good reason to brave the cold, as the Geminid meteor shower peaks on the morning of Sunday, December 14th. The Geminids are dependable, with a broad peak spanning several days, and would be as well known as their summer cousins the Perseids, were it not for the fact that they transpire in the dead of northern hemisphere winter.

But do not despair. While some meteor showers are so ephemeral as to be considered all but mythical in the minds of most meteor shower observers, the Geminids always deliver. We most recently caught a memorable display of the Geminids in 2012 from a dark sky locale in western North Carolina. Several meteors per minute pierced the Appalachian night, offering up one of the most memorable displays by this or any meteor shower in recent years.

The Geminids are worth courting frostbite for, that’s for sure. But there’s a curious history behind this shower and our understanding of meteor showers in general, one that demonstrates the refusal of some bodies in our solar system to “act right” and fit into neat scientific paradigms.

UK Meteor Observation Network
A composite of the 2013 Geminids. Credit: the UK Meteor Observation Network

It wasn’t all that long ago that meteor showers — let alone meteorites — were not considered to be astronomical in origin at all. Indeed, the term meteor and meteorology have the same Greek root meaning “of the sky,” suggesting ideas of an atmospheric origin. Lightning, hail, meteors, you can kind of see how they got there.

In fact, you could actually face ridicule for suggesting that meteors had an extraterrestrial source back in the day. President Thomas Jefferson was said to have done just that concerning an opinion espoused by Benjamin Silliman of a December 14th, 1807, meteorite fall in Connecticut, leading to the apocryphal and politically-tinged response attributed to the president that, “I would more easily believe that two Yankee professors would lie, than that stones would fall from heaven.”

Indeed, no sooner than The French Academy of Sciences considered the matter settled earlier in the same decade, then a famous meteorite fall occurred in Normandy on April 26th, 1803,… right on their doorstep. The universe, it seemed, was thumbing its nose at scientific enlightenment.

A fine Geminid
A fine 2004 Geminid as imaged by Frankie Lucena.

Things really heated up with the spectacular display known as the Leonid meteor storm in 1833. On that November morning, stars seemed to fall like snowflakes from the sky. You can imagine the sight, as the Earth plowed headlong into the meteor stream. The visual effect of such a storm looks like the starship Enterprise plunging ahead at warp speed with stars streaming by, as if imploring humanity to get hip to the fact that meteor showers and their radiants are indeed a reality.

Still, a key problem persisted that gave ammunition to the naysayers: no new “space rocks” were found littering the ground at sunrise after a meteor shower. We now know that this is because meteor showers hail from wispy cometary debris left along intersections of the Earth’s orbit.  Meteorite Man Geoff Notkin once mentioned to us that no meteorite fall has ever been linked to a meteor shower, though he does get lots of calls around Geminid season.

The name of the game in the 19th century soon became identifying new meteor showers. Streams evolve over time as they interact with planets (mostly Jupiter), and the 19th century played host to some epic meteor storms such as the Andromedids that have since been reduced to a trickle.

The Geminids are, however, the black sheep of the periodic meteor shower family. The shower was first noticed by US and UK observers in 1862, and by the 1870s astronomers realized that a new minor shower with a Zenithal Hourly Rate (ZHR) hovering around 15 was occurring near the middle of December from the constellation Gemini.

NASA
A possible early 2014 Geminid and the near Full Moon as seen by NASA’s All Sky Fireball Network.

The source of the Geminids, however, was to remain a mystery right up until the late 20th century.

In the late 1940s, astronomer Fred Whipple completed the Harvard Meteor Project, which utilized a photographic survey that piqued the interest of astronomers worldwide: debris in the Geminid stream appeared to have an orbital period of just 1.65 years, coupled with a high orbital inclination. Modeling suggested that the parent body was most likely a short period comet, and that the stream had undergone repeated perturbations courtesy of Earth and Jupiter.

In 1983, the culprit was found, only to result in a deeper mystery. The Infrared Astronomical Satellite (IRAS) discovered an asteroid fitting the bill crossing the constellation Draco. Backup observations from the Palomar observatory the next evening cinched the discovery, and today, we recognize the source of the Geminids as not a comet — as is the case with every other major meteor shower — but asteroid 3200 Phaethon, a 5 kilometre diameter rock in a 524 day orbit.

3200 Phaethon
Asteroid 3200 Phaethon (arrowed) imaged by Marco Langbroek from the Winer Observatory in Sonita, Arizona. Credit: Wikimedia Commons.

So why doesn’t this asteroid behave like one? Is 3200 Phaethon a rogue comet that has long since settled down for the quiet space rock life? Obviously, 3200 Phaethon has lots of material shedding off from its surface, as evidenced by the higher than normal ratio of fireballs seen during the Geminid meteors. 3200 Phaethon also passes 0.14 AUs from the Sun — 47% closer than Mercury — and has the closest perihelion of any known asteroid to the Sun, which bakes the asteroid periodically with every close pass.

One thing is for certain: activity linked to the Geminid meteor stream is increasing. The Geminids actually surpassed the Perseids in terms of dependability and output since the 1960s, and have produced an annual peak ZHR of well over 100 in recent years. In 2014, expect a ZHR approaching 130 per hour as seen from a good dark sky site just after midnight local on the morning of December 14th as the radiant rides high in the sky. Remember, this shower has a broad peak, and it’s worth starting your vigil on Saturday or even Friday morning. The Geminid radiant also has a steep enough declination that local activity can start before midnight… also exceptional among meteor showers. This year, the 52% illuminated Moon rises around midnight local on the morning of December 14th.

Credit: Stellarium
The Geminid radiant looking to the northeast at 11PM local. Note the radiant of the December 22nd Ursids is also nearby. Credit: Stellarium.

And there’s another reason to keep an eye on the 2014 Geminids. 3200 Phaethon passed 0.12 AU (18 million kilometers) from Earth on December 10th, 2007, which boosted displays in the years after. And just three years from now, the asteroid will pass even closer on December 10th, 2017, at just 0.07 AUs (10.3 million kilometers) from Earth…

Are we due for some enhanced activity from the Geminids in the coming years?

All good reasons to bundle up and watch for the “Tears of the Twins” this coming weekend, and wonder at the bizzaro nature of the shower’s progenitor.

 

101 Astronomical Events for 2014

It’s here!

As 2013 draws to a close, we once again cast our thoughts to all things astronomical for the coming year. For the past five years, I’ve been constructing this list of all things astronomical for the coming year, lovingly distilling the events transpiring worldwide down to a 101 “best events of the year”. This is the first year this list has been featured on Universe Today, so we’ll lay out our ground rules and reasoning a bit as to selection criteria.

Events selected run the gamut from conjunctions and eclipses that are visible worldwide or over a good swath of the planet, to asteroid occultations of stars that are only visible along a thin path along the surface of the Earth. Geocentric conjunction times for occultations are quoted. Generally, only conjunctions involving bright stars, planets & the Moon are noted. The intent of this list is to bridge the gap between the often meager “10 Best Astronomy Events of 2014” listicles that make their rounds this time of year and the more tedious laundry lists of Moon phases and wide conjunctions.

As always, we look at the coming year with an eye out for the astronomically curious and the bizarre. Times are quoted in Universal Time (UT) using a 24-hour clock, which is identical to Greenwich Mean Time (GMT) and Zulu for those in the military.

Some caveats as to how selections were made:

-To make the cut, asteroid occultations must have a rank of 99 or greater, and occult a star brighter than +8th magnitude.

– We only selected major annual meteor showers with a Zenithal Hourly Rate (ZHR) projected to be 20 or greater.

– Only lunar occultations of planets and bright stars are listed.

– Solstice seasons where the International Space Station reaches full illumination are approximate; the ISS gets boosted periodically, and therefore it’s impossible to project its precise orbit months in advance.

– Comets come and go. The comets included on this list are some of the “best bets” that are forcasted to reach binocular visibility for 2014. A big bright one could come up and steal the show at any time!

This list was meant to “whet the appetite” for what’s coming to skies worldwide in 2014 with a succinct rapid fire listing by month. Where an online resource exists that expands on the event, we linked to ‘em. A full resource list, both paper and cyber, is given at the end of the post. Print these events, post it on your refrigerator and/or observatory wall, and expect us to feature many these fine events on Universe Today in the coming year!

Some notes on 2014:

2014 sees Mars reach opposition in early April, which is sure to be a highlight as we head towards an exceptionally close opposition in 2018.

The month of February is also missing a New Moon, which last occurred in 1995 and won’t happen again until 2033. February is the only calendar month which can be missing the same moon phase twice!

We’re also coming off a profoundly weak solar maximum in 2014, though as always, the Sun may have some surprises in store for solar observers and aurora watchers worldwide.

The motion of the Moon in 2014 is headed towards a “shallow” year in 2015 relative to the ecliptic; it will then begin to slowly open back up and ride high around 2025.

2014 also contains the minimum number of eclipses that can occur in one year, 2 solar and 2 lunar. And while there are no total solar eclipses in 2014, there are two fine total lunar eclipses, both visible from North America.

And here’s the month by month rundown:

Moon Jan 1
The view looking west from the US east coast at 6 PM on January 1st from latitude 30 degrees north. (Created in Stellarium).

January

01- The extremely thin crescent 12-15 hour old Moon will present a challenge for North American viewers low to the west at dusk.

03- Quadrantid meteors peak with a ZHR=120 at ~05:00 UT, best seen from the Atlantic region. Favorable in 2014, with the Moon a 2 day old waxing crescent.

04- Earth reaches perihelion at 12:00 UT, 147.1 million kilometres from the Sun.

04- Mars passes 1.3’ from the +11.5th magnitude galaxy NGC 4684.

05- Jupiter reaches opposition for 2014 and shines at magnitude -2.7.

10- A Possible meteor shower due to dust from the Comet (formerly known as) ISON over the next few days?

11- Venus reaches inferior conjunction between the Sun and the Earth, shining at -4th magnitude. It may be just possible to spot it five degrees north of the solar limb from high northern latitudes.

13- Moon reaches its farthest northern declination for 2014 a 19.4 degrees.

16- The most distant Full Moon, and visually smallest Full Moon of 2014 occurs, with the Moon reaching Full within two hours of apogee. MiniMoon!

25- The Moon occults Saturn for the South Pacific at ~13:58 UT.

27- The Moon reaches its farthest southern declination for 2014, at -19.3 degrees.

30- A Black Moon occurs, as reckoned as the second New Moon in a month with two.

31- Mercury reaches a favorable elongation, shining at magnitude -0.9, 18.4 degrees east of the Sun.

Venus occultation footprint for
Venus occultation footprint for February 26th. (Created using Occult v4.1.0).

February

06- Two shadows transit the cloud tops of Jupiter from 10:20 UT-12:44 UT, favoring western North America.

21- The Moon occults Saturn for the Indian Ocean at ~22:18 UT.

26- The 14% waning crescent Moon occults Venus for central Africa at ~5:23 UT.

March

07- Asteroid 9 Metis occults a +7.9 magnitude star for Europe ~3:14 UT.

10- The 70% illuminated waxing gibbous Moon occults the +3.6 magnitude star Lambda Geminorum for North America in the evening sky.

14- Mercury reaches greatest morning elongation at 27.5 degrees west of the Sun shining at magnitude +0.1. Mercury’s best morning apparition in 2014 for southern hemisphere observers.

16- A double shadow transit of Jupiter’s moons occurs from 22:20 to 00:35 UT, visible from Atlantic Canada after sunset.

20- The Northward Equinox occurs at 16:57 UT.

20- GEO satellite eclipse season occurs, as geostationary satellites enter Earth’s shadow near the equinox.

20- Regulus is occulted by asteroid 163 Erigone for the NE United States and Canada at ~6:07 UT, The brightest star occulted by an asteroid in 2014.

21- The Moon occults Saturn for the South Atlantic at ~3:18 UT.

24- A double shadow transit of Jupiter’s moons occurs from 2:08 to 2:28 UT, favoring eastern North America.

24- Asteroid 172 Baucis occults a +6.7 magnitude star for South America at ~9:27 UT.

22- Venus reaches greatest morning elongation, at 47 degrees west of the Sun.

28- Asteroid 51 Nemausa occults a +7.7 magnitude star for Africa at 20:02 UT.

30- A Black Moon occurs, as reckoned as the second New Moon in one month.

The viewing prospects for the April 15th Total Lunar Eclipse. (Credit: NASA/GSFC/
The viewing prospects for the April 15th Total Lunar Eclipse. (Credit: NASA/GSFC/Espenak/Meeus).

April

08- Mars reaches opposition for 2014, shining at magnitude -1.5.

12- A close conjunction of Venus and Neptune occurs, with the planets just 0.7 degrees apart at 2:00 UT.

15- A Total Lunar Eclipse occurs, visible from the Americas and centered on 7:47 UT.

17- The Moon occults Saturn for South America at ~7:19 UT.

29- An Annular Solar Eclipse visible from Australia and the southern Indian Ocean occurs, centered on 6:05 UT. This is a unique, non-central antumbral eclipse!

May

03- Asteroid 105 Artemis occults a +7.7 magnitude star for NW Brazil and Peru at ~9:17 UT.

04- Asteroid 34 Circe occults a +7.4 magnitude star for Peru and Ecuador at ~10:12 UT.

06- The closest lunar apogee of 2014 occurs at 404,318 km distant at 10:23 UT.

07- Eta Aquariid meteors peak, with a ZHR=55 at 4:00 UT. Best observed from the Atlantic Region. Favorable in 2014, with the 7-day old Moon at waxing gibbous.

07- Asteroid 206 Hersilia occults a +7.5 magnitude star for Australia and Indonesia at ~17:49 UT.

10- Saturn reaches opposition for 2014, shining at magnitude +0.1. Saturn’s rings are tipped open a maximum of 23 degrees to our line of sight on February 11th, and widening overall in 2014.

13- A double shadow transit of Jupiter’s moons occurs from 9:20-9:32 UT favoring NW North America.

14- The Moon occults Saturn for Australia and New Zealand at ~12:18 UT.

24- A meteor shower outburst may be in the offing, courtesy of Comet 209P LINEAR. Will the “Camelopardalids” perform?

24- Asteroid 33 Polyhymnia occults a +5.5 magnitude star for South America at ~8:30 UT.

25- Mercury reaches maximum dusk elongation, 22.7 degrees east of the Sun. Mercury’s best evening apparition for 2014 for northern hemisphere viewers.

The triple shadow transit of June 3rd, as seen at 18:00 UT. (Created by the author using Starry Night).
The triple shadow transit of June 3rd, as seen at 19:00 UT. (Created by the author using Starry Night).

 June

3- A triple Jovian shadow transit occurs from 18:05-19:44 UT, favoring eastern Europe and Africa. This is the only triple shadow transit for 2014.

10- The Moon occults Saturn for the southern Indian Ocean at ~18:48 UT.

21- The Northward Solstice occurs at ~10:51 UT.

22- The International Space Station enters a period of full illumination near the June solstice, favoring multiple views for northern hemisphere viewers.

24- The waning crescent Moon passes within a degree of Venus, a great time for spotting the planet in the daytime.

26- The Moon occults Mercury just 20 hours prior to New… a tough catch, but may visible from the SE US and Venezuela just before sunrise.

27- The June Boötid meteors peak, with a ZHR variable from 0-100 at ~15:00 UT, favoring the Central Pacific. Optimal in 2014, as the Moon is at New phase.

July

04- Earth reaches aphelion at 2:00 UT, at 152,098,232 kilometres from the Sun.

04- Pluto reaches opposition at 3:00 UT.

05– 1 Ceres passes just 10’ from 4 Vesta in the constellation Virgo.

06– The Moon occults Mars for South America at ~01:21 UT

08– The Moon occults Saturn for Argentina & Chile at ~2:25 UT.

12- Mercury reaches its maximum elongation of 20.9 degrees west of the Sun, shining at magnitude +0.4 in the dawn.

12– The first Full Proxigean “Super” Moon (1 of 3) for 2014 occurs at 11:27 UT. The Moon reaches Full 21 hours prior to perigee.

30– The Southern Delta Aquarids peak, with a ZHR=20. Time variable, favorable in 2014 with the waxing crescent Moon 4 days past New.

20– Asteroid 451 Patientia occults a +7.1 magnitude star for South Africa at ~17:15 UT.

28- The farthest lunar apogee of 2014 occurs, with the Moon 406,568 kilometres distant at 3:28 UT.

30– Asteroid 103 Hera occults a +6.1 magnitude star for west Africa and central South America at ~1:11 UT.

A tri-conjunction of the Moon, Venus & Jupiter- A "Skewed Smiley face" conjunction!" Credit:  Stellarium
A tri-conjunction of the Moon, Venus & Jupiter on the morning of August 23rd- A “Skewed Smiley face” conjunction!” Credit: Stellarium).

August

02– A close conjunction of Mercury and Jupiter occurs, with the planets just 0.9 degrees apart at 19:00 UT. Visible in SOHO’s LASCO C3 camera.

04- The Moon occults Saturn for Australia at ~10:31 UT.

10– The closest lunar perigee of 2014 occurs, with the Moon 356,896 kilometres distant at 17:44 UT.

10- The Closest Full Moon of the year & “Super” Moon (2 of 3) for 2014 occurs, with Full Moon occurring just 27 minutes after perigee.

13– The Perseid meteors peak, with a ZHR=100 at ~04:00 UT favoring The Atlantic region. Unfavorable in 2014, with the 17 day old Moon at waning gibbous.

18- A conjunction of Venus and Jupiter occurs 5:00 UT, the closest conjunction of two naked eye planets in 2014, with the two just 15’ apart.

29- Neptune reaches opposition at 14:00 UT, shining at +7.8 magnitude.

31– The Moon occults Saturn for Africa and the eastern US (in the daytime) at ~18:59.

September

05- Venus passes 0.7 degrees from the bright star Regulus.

09– The final Full “Super” Moon (3 of 3) for 2014 occurs at 1:39 UT, just 22 hours after perigee.

15– Comet C/2013 V5 Oukaimeden may reach +5.5th magnitude for southern hemisphere observers.

20– Mercury passes 0.5 degrees south of the bright star Spica at 21:00 UT.

21- Mercury reaches its greatest elongation of 26.4 degrees east of the Sun shining at magnitude +0.0 in the dawn sky. Mercury’s best sunset apparition for 2014 for southern hemisphere observers.

23- The Southward Equinox occurs at 2:29 UT.

23- GEO satellite eclipse season occurs, as geostationary satellites enter Earth’s shadow near the equinox.

28– The Moon occults Saturn for the northern Pacific at ~4:25 UT. The Moon also occults 1 Ceres and 4 Vesta on the same day!

The path of Comet C/2013 A1 Siding Springs versus the planet Mars through October, 2014. (Created by the author using Stellarium).
The path of Comet C/2013 A1 Siding Springs versus the planet Mars through October, 2014. (Created by the author using Starry Night).

 October

04- 1 Ceres passes just 30’ north of Saturn.

06- Possible Draconid meteor shower, highly variable in terms of rates and timing, but unfavorable in 2014, with the Moon just two days from Full.

08- A Total Lunar Eclipse visible from the Pacific Rim region occurs, centered on 10:56 UT. The planet Uranus will also lie less than a degree away from the eclipsed Moon!

14- Comet C/2012 K1 PanSTARRS may reach +5th magnitude for southern hemisphere viewers.

13– The Moon reaches it shallowest northern declination for 2014 at +18.5 degrees.

19- Comet C/2013 A1 Siding Spring passes just 7’ from the planet Mars. Globular cluster NGC 6401 also lies nearby.

22– The Orionid meteor shower peaks at ~05:00 UT, with a predicted ZHR=25 favoring the Americas. Optimal in 2014, with the Moon at waning crescent.

22– The Moon occults Mercury for Australia just 24 hours prior to New as seen from Australia.

23- A Partial Solar Eclipse visible from western North America occurs centered on 21:46 UT.

25- The Moon occults Saturn for the northern Atlantic at ~15:43 UT.

25- The Moon reaches its shallowest southern point for 2014, at a declination of -18.6 degrees.

The partial solar eclipse of October 23rd, 2014. (Credit: NASA/GSFC/Fred Espenak).
The partial solar eclipse of October 23rd, 2014. (Credit: NASA/GSFC/Fred Espenak).

 November

01- Mercury reaches its greatest elongation 18.7 degrees west of the Sun, shining at magnitude -0.5. The best morning apparition of Mercury for 2014 as seen from the northern hemisphere.

18– Leonid meteors peak at 05:00 UT with a ZHR=20 favoring the Atlantic region. Optimal in 2014, with the 25 day old Moon at waning crescent phase.

20- Asteroid 3 Juno occults a +7.4 magnitude star for the US NE and eastern Canada.

27- The farthest lunar perigee of 2014 occurs with the Moon 369,824 km distant at 23:12 UT.

December

09- A double shadow transit of Jupiter’s moons occurs from 4:18 to 4:27 UT favoring eastern North America.

12- A double shadow transit of Jupiter’s moons occurs from 16:19 to 16:44 UT favoring NW North America.

13- The Geminid meteors peak with a ZHR=120 at ~01:00 UT, favoring the Middle East & Eastern Europe. Unfavorable in 2014, with the 20 day old  Moon at waning gibbous.

18- Asteroid 702 Alauda occults a +6.2 magnitude star at 14:12 UT for eastern Australia.

21- The Southward Solstice occurs at 23:03 UT.

21- The International Space Station enters period of full illumination around the solstice, with multiple nightly views favoring the southern hemisphere.

21- A double shadow transit of Jupiter’s moons occurs from 14:17 to 15:55 UT, favoring the Far East and Australia.

Don’t see your favorite or most anticipated event of 2014 on the list? Drop us a line and let us know!

Links & Resources Used:

-The American Meteor Society list of 2014 showers

-NASA’s Eclipse Website

-The United States Naval Observatory’s Astronomical Almanac Online

-Guy Ottewell’s 2014 Astronomical Calendar

-The Royal Astronomical Society of Canada’s 2014 Observer’s Calendar

-Steve Preston’s list of asteroid occultation events for 2014

Stellarium

Starry Nite

-Seiichi Yoshida’s Comet website

-Fourmilab’s Lunar Apogee and Perigee calculator

Heavens-Above

-The International Occultation Timing Association’s list of lunar occultations for 2014.

And finally, thanks to all of those too numerous to name who provided discussions/diatribes/input via Twitter/G+/message boards/etc to make this listing possible… let another exciting year of astronomy begin!