You might just see a few meteors from the combined Arietids and Zeta Perseid showers that peak Friday and Saturday mornings. This map shows the sky facing northeast at dawn for the mid-section of the U.S. Created with Stellarium
I’ve never seen an Arietid meteor and chances are you haven’t either. Peaking on June 7-8, the Arietid (AIR-ee-uh-tid) meteor shower is one of the strongest of the year with a maximum rate of 50-80 per hour. But there’s a rub. The shower radiant, the point in the sky from which the meteors appear to radiate, is near the sun and best seen during daylight hours. When was the last time you saw meteors in daylight?
Early scientific exploration of the sky in radio waves at Jodrell Bank Observatory in 1945. Credit: Jodrell Bank, University of Manchester
If you’re wondering how anyone could discover a meteor shower when the sun is out, it’s impossible unless your eyes can see radio waves. The Arietids were first “seen” in 1947 by operators of radio equipment at Jodrell Bank Observatory in England. Meteors leave trails of ionized gases when they rip through our upper atmosphere at tens of thousands of miles per hour and briefly make ideal reflectors of radio waves.
You can even hear them yourself by tuning to a “blank” spot between stations on an FM radio and listening for sudden bursts of talk or music when the meteor trail boosts a neighboring station into audibility. Click HERE for simple instructions if you’d like to give it a try.
The Arietids are joined by a second daytime shower at the same time by the Zeta Perseids, a smaller shower, to guarantee a couple busy days of meteor-listening — and potential meteor-watching — on and around June 7-8. Most meteor showers are tied to a particular comet, since they’re swarms of dusty detritus left behind in a comet’s wake as it travels ’round the sun. When Earth intersects the stream, tiny comet bits slam into the atmosphere, heat up to 3,000 F or more and self-immolate in glowing streaks we call meteors. Occasionally a shower’s parent can be an asteroid as in the case of the January Quadrantid meteor shower. It’s suspected that the asteroid 2003 EH1 may be a extinct comet.
Most meteors are comet dust striking at the atmosphere at speeds so high, they vaporiz in a blaze of light. This is a meteor from the Leonid shower in 2001. Credit: Bob King
No one’s certain of the Arietids’ parentage. Likely candidates include the near-Earth asteroid 1566 Icarus and Comet 96P/Machholz, both of which have orbits that resemble the shower’s.
After ignoring May’s Eta Aquarid meteor shower for years because of its very low radiant at dawn, I was pleasantly surprised by the many meteors I saw when I happened to catch the shower at maximum on May 6 this year. Circumstances are only slightly worse for the Arietids. That’s why I think it’s worth your while to check out this shower tomorrow (Friday) and Saturday morning(June 7-8). Face east and start watching an hour or two before the start of dawn and continue your vigil until the sky brightens in the east.
The lesser Zeta Perseids are also active, adding to the fun. Since the two shower radiants are close to each other in the sky, it may be hard to tell which you’re seeing. No matter. Any fiery streaks you can trace back toward the east-northeast horizon will likely be one or the other.
Earth-grazing meteor photographed by Manuel Conde of Barcelona, Spain.
Whenever a radiant is near the horizon, many of the meteors approaching us do so at a very shallow angle almost horizontal to the Earth’s atmosphere. From our perspective they travel slowly and last a much longer time than do meteors striking the air at a steeper angle, typical for radiants that are higher in the sky.
Astronomers use the poetic “Earth-grazers” to describe them. Having seen a handful of these unique beauties during the May Aquarid shower, I’m hungry for more. Since the Arietids / Zeta Perseids also originate low in the sky, we should expect similar sights Friday and Saturday mornings.
A meteor from the Eta Aquarids flashes over the iconic Stonehenge. Credit and copyright: Peter Greig.
Astrophotographer Peter Greig (St1nkyPete on Flickr) had always wanted to go to Stonehenge in Wiltshire, England, and chose to go there this year for his birthday. It turns out the Universe gave him a little birthday present, with a fabulous clear evening to see the Milky Way shining overhead, along with a few Eta Aquarid meteors flashing in the sky. He captured this amazing shot on May 12. Happy birthday, Peter!
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The radiant of the Eta Aquarids rising. Looking to the south east from latitude 30 degrees north about 3 hours before local sunrise on May 5th. (Created by the author in Stellarium).
An often ignored meteor shower may offer fine prospects for viewing this weekend.
The Eta Aquarid meteors provide a dependable display in early May. With a radiant very near a Y-shaped asterism in northern Aquarius, the Eta Aquarids are one of the very few major showers that provide a decent annual show for southern hemisphere residents.
This year, the peak of the Eta Aquarids as per the International Meteor Organization (IMO) comes on May 6th at 1:00 UT, or 9:00 PM EDT on May 5th. This favors European longitudes eastward on the morning of Monday, May 6th. The Eta Aquarid radiant rises just a few hours before dawn, providing optimal viewing in the same time frame.
Keep in mind, the shower is active from April 19th to May 28th. Predicting the arrival of the peak of a meteor shower can be an inexact science. North American observers may still see an early arrival of the Eta Aquarids on May 5th or even the morning of the 4th.
Could “the 4th be with us” at least in terms of meteor shower activity?
The Eta Aquarids are one of two annual meteor showers associated with that most famous of comets: 1P/Halley. The other shower associated with Halley’s Comet is the October Orionids. This makes it one of the very few periodic comets associated with two established annual meteor showers.
Like the Orionids, the Eta Aquarid meteors have one of the highest atmospheric velocities of any shower, at 66 kilometres per second. Expect short, swift meteors radiating from low in the southeast (or northeast if you’re based south of the equator) a few hours before local dawn.
This year’s ZHR is expected to reach 55. This year also offers outstanding prospects, because the Moon is only a 17% illuminated waning crescent just 4 days from New at the shower’s peak. There’s some thought in the meteor observing community that this shower experiences a cyclical peak every 12 years.
If this is indeed the case, we could be headed towards a mild lull in this shower around the 2014 to 2016 time frame. Performances from the Eta Aquarids over the past few years as per data from the IMO seem to bear this out, with a peak around 2009;
2012=ZHR 69
2011=ZHR 63
2010=No data
2009=ZHR 90
2008=65
Still, 55 per hour is a respectable shower. Keep in mind, the ZHR stands for the “Zenithal Hourly Rate” and is an ideal number. This is the number of meteors an observer could expect to see under dark skies with no light pollution with the radiant directly overhead. Also, remember that no single observer can monitor the entire sky at once!
This is also one of the last big annual showers of the season until the Perseids in mid-August. The Gamma Delphinids (June 11th) and the June Bootids (Jun 27th and the June Lyrids (June 15th) are the only minor showers in June. July also sees another minor shower radiating from the constellation Aquarius, the Delta Aquarids which peak on July 30th. The daytime Arietids in June would put on a fine annual showing if they didn’t occur in… you guessed it… the daytime.
This weekend’s Eta Aquarids will put on a better display for the southern hemisphere, one of the very few showers for which this is true.
It’s a poorly understood mystery. Why does the northern celestial hemisphere seem to contain a majority of major meteor shower radiants? The Geminids, the Leonids, the Perseids, the Quadrantids… all of these showers approach the Earth from above the celestial equator, and even from above the ecliptic plane. The Eta Aquarids are one of the very few major showers that goes against this trend.
Is it all just a coincidence? Perhaps. Like total solar eclipses, meteor showers are as much a product of our position in time as well as space. New streams are shed as comets visit the inner solar system, some for the very first time. These older trails interact with and are dispersed by subsequent passages near planets. The 12 year fluctuation of the Eta Aquarids is thought to be related to the orbit of Jupiter which has a similar period.
For example, one meteor shower known as the Andromedids was prone to epic storm outbursts until the early 20th century. Now the stream is a mere trickle. Meteor showers evolve over time, and perhaps their seeming affinity for the northern hemisphere of our planet is a mere perception of our epoch. Maybe a future study could discern a bias due to the number of prograde versus retrograde cometary orbits, or perhaps statistical scrutiny could reveal that no such partiality actually exists.
All food for thought as you keep vigil these early May mornings for the meteoric “Drops from the Water Jar…” Be sure to post those meteor pics to the Universe Today’s Flickr forum, report those meteor counts to the International Meteor Organization, and tweet those fireball sightings to #Meteorwatch!
Talk about a light show! A massive bolide was captured on video during a middle-of-the-night rock concert in Argentina on April 21, 2013. The band, Los Tekis performed at an outdoor concert venue and in perfect timing, right after the band concluded a song, the person who shot the video panned out so that the sky was visible — just as the bolide lit up the sky. Continue reading “Bright Meteor Rocks Argentina Rock Concert”
The 2013 Lyrid meteors as seen from Windy Point Vista on Mt. Lemmon, Tucson Arizona. (Credit & copyright Sean Parker Photography. In the Universe Today flickr gallery).
Today we residents of planet Earth meet up with a meteor stream with a strange and bizarre past.
The Lyrid meteors occur annually right around April 21st to the 23rd. A moderate meteor shower, observers in the northern hemisphere can expect to see about 20 meteors in the early morning hours under optimal conditions. Such has been the case for recent years past, and this year’s presence of a waxing gibbous Moon has lowered prospects for this April shower considerably in 2013.
But this has not always been the case with this meteor stream. In fact, we have records of the Lyrids stretching back over the past 2,600 years, farther back than any other meteor shower documented.
The earliest account of this shower comes from a record made by Chinese astronomers in 687 BC, stating that “at midnight, stars dropped down like rain.” Keep in mind that this now famous assertion that is generally attributed to the Lyrids was made by mathematician Johann Gottfried Galle in 1867. It was Galle along with Edmond Weiss who noticed the link between the Lyrids and Comet C/1861 G1 Thatcher discovered six years earlier.
Comet Thatcher was discovered on April 5th, 15 days before it reached perihelion about a third of an astronomical unit (A.U.) from the Earth. Comet Thatcher a periodic comet on a 415 year long orbital period.
But in the early to mid-19th century, the very idea that meteor showers were linked to comets or even non-atmospheric phenomena was still hotly contested.
One singular event more than any other triggered this realization. The Leonid meteor storm of 1833 in the early morning hours of November 13th was a stunning and terrifying spectacle for residents of the U.S eastern seaboard. This shower produces mighty outbursts, often topping a Zenithal Hourly Rate (ZHR) of over a 1,000 once every 33 to 34 years. I witnessed a fine outburst of the Leonids from Kuwait in 1998, and we may be in for a repeat performance from this shower around 2032 or 2033.
There is substantial evidence that the Lyrids may also do the same at an undetermined interval. On April 20th 1803, one of the most famous accounts of a “Lyrid meteor storm” was observed up and down the United States east coast. For example, one letter to the Virginia Gazette states;
“From one until three, those starry meteors seemed to fall from every point in the sky heavens, in such numbers as to resemble a shower of sky rockets.”
Another account published in the Raleigh, North Carolina Register states that:
“The whole hemisphere as far as the extension of the horizon seemed illuminated; the meteors kept no particular direction but appeared to move in every way.”
A study of the 1803 Lyrid outburst by W.J. Fisher cites over a dozen accounts of the event and is a fascinating read. Viewers were also primed for the event by the dramatic Leonid storm of 1799 four years earlier.
Interestingly, the Moon was only one day from New phase on the night of the 1803 Lyrids. Prime meteor watching conditions.
An unrelated meteorite fall would also occur four years later over Weston, Connecticut on December 14th, 1807 as recounted by Kathryn Prince in A Professor, A President, and a Meteor. These events would place Yankee politics at odds with the origin of meteors and rocks from the sky.
An apocryphal quote is often attributed to President Thomas Jefferson that highlights the controversy of the day, saying that “I would more easily believe that two Yankee professors would lie than that stones would fall from heaven.”
While both are of cosmogenous origin, no meteorite fall has ever been linked to a meteor shower, which is spawned by dust debris from comets. For example, many in the media erroneously speculated that the Sutter’s Mill meteorite that fell to Earth on the morning of April 22nd, 2012 was in fact a Lyrid meteor.
But a Lyrid may be implicated in another unusual 19th century observation. On April 24th 1874, a professor Scharfarik of Prague, Czechoslovakia was observing the daytime First Quarter Moon with his 4” refractor. The good professor was surprised by an “Apparition on the disc of the Moon of a dazzling white star,” which was “quite sharp and without a perceptible diameter.” Possible suspects are a telescopic meteor moving towards or along the observers’ line of sight or perhaps a Lyrid impacting the dark limb of the Moon.
Moving into the 20th century, rates for the Lyrids have stayed in the ZHR=20 range, with notable peaks of 100+ per hour noted by Japanese observers in 1922 and 100 per hour noted by U.S. observers in 1982.
It should also be noted that another less understood shower radiates from the constellation Lyra in mid-June. First noted Stan Dvorak while hiking in the San Bernardino Mountains in 1966, the June Lyrids produce about 8-10 meteors per hour from June 10 to the 21st. The source of this newly discovered shower is thought to be Comet C/1915 C1 Mellish.
A June Lyrid may have even made its way into modern fiction. As recounted in a July 2004 issue of Sky & Telescope, researchers Marilynn & Donald Olson note the following line from James Joyce’s Ulysses:
“A star, precipitated with great apparent velocity across the firmament from Vega in the Lyre above the zenith.”
Joyce seems to be describing a June Lyrid decades before the shower was officially recognized. The constellation Lyra rides high in the early morning sky for mid-northern latitudes in the early summer months.
All interesting concepts to ponder as we keep an early morning vigil for the Lyrids this week. Could there be more Lyrid storms in the far off future, as Comet Thatcher reaches perihelion once again in the late 23rd century? Could more historical clues of the untold history of this and other showers be awaiting discovery?
Somewhat closer to us in time and space, Paul Wiegert of the University of Ontario has also recently speculated that Comet 2012 S1 ISON may provoke a meteor shower on January 12th, 2014. Regardless of whether ISON turns out to be the “Comet of the Century,” this could be one to watch out for!
Lyrid meteors will appear to radiate (red circle) from a point near the bright star Vega in the constellation Lyra. This map shows the sky facing southeast around 3:30 a.m. April 22 - around the time of maximum. Stellarium
Feeling a little meteor-starved lately? Me too. It’s been a meteor shower desert since the Quadrantids of early January. That’s about to change. This weekend brings the celestial version of April showers with the annual appearance of the Lyrids.
The Lyrids ding the bell at maximum strength this weekend April 21-22 (Sunday night-Monday morning in the Americas) hurtling meteors at the modest rate of 10-20 per hour from a point in the sky not far from bright Vega in the constellation Lyra. While some showers spread their meteor crumbs over several days, the Lyrids’ peak activity lasts less than a day. The western hemisphere – particularly the western half of North America – is favored this year.
A Lyrid meteor captured by NASA astronaut Don Pettit out the window of the International Space Station on April 21, 2012. The lights of Florida are visible to the right of the meteor. Click to enlarge. Credit: NASA
There will be a small price to pay for the show. The Lyrid radiant, the point in the sky from which the showers members radiate, rises in the east rather late – around 10:30 p.m. local time. Then there’s the bright gibbous moon, which has a habit of drowning out fainter stars and meteors alike. That makes the best time for viewing the shower after moonset or around 4 a.m. Monday morning. Since dawn begins about 5, you’ll have one good hour. That’s plenty of time to snag at least a few flaming motes of Comet Thatcher.
A bright fireball meteor in twilight. The Lyrids, like all meteor showers, offer up the occasional fireball among a mix of fainter meteors. Credit: John Chumack
Like most meteor showers, the Lyrids have a parent and single parents are the rule. For the Lyrids, it’s Comet Thatcher, discovered on April 5, 1861, a week before the start of the Civil War, by amateur astronomer A.E. Thatcher observing from New York City. Later it was found to be linked to the Lyrid meteor shower.
Each year in late April, Earth passes through centuries of dust shed by the comet’s tail. When bits of Thatcher flotsam strike the air some 60-70 miles high, they burn up in flashes of meteoric light. Comet tears.
The delicate, rarefied dust tail of Comer C/2012 K5 in Dec. 2012. If Earth happens to intersects a comet’s dusty orbit – as we do with Comet Thatcher every April – we witness a meteor shower. Credit: Michael Jaeger
All meteors are worthy of keeping an eye on, but bear in mind that the Lyrids are no Perseids, the famed summertime shower offering up to 60 meteors per hour under dark skies. But what they lack in numbers, they make up in reliability and surprise.
Records indicate that people have been watching the Lyrids for at least 2,600 years, the longest of any shower. Our oldest descriptions come from the Chinese who penned that “stars fell like rain” on March 16, 687 BC. Apparently the shower was more active in the past and has since evolved into a minor display. But there have been occasional surprises, and that’s what keeps the Lyrids interesting.
Comet Thatcher circles the sun once every approxiimately 415 years. Each time it does, the comet leaves dust and small bits of ice and rock in a trail behind it. Sometimes it sheds more dust than others, creating denser filaments that can make for unexpectedly high numbers of Lyrid meteors when the Earth passes through. Not to scale. Illustration: Bob King
On April 20, 1803 a fire bell roused Richmond, Virginia residents from their beds to witness a similar rain of stars when up to 700 meteors per hour were seen. Other Lyrid outbursts occurred in 1922 (100 per hour), 1945 (100/hr), 1982 (90/hour). Last year’s peak hit 37 per hour from a dark sky site. Now and then, Earth encounters a thicker band of comet debris left behind by Comet Thatcher, suddenly increasing the meteor count by many times and just as suddenly dropping back to the usual 10-20 per hour.
So here’s the bottom line. Don’t expect a big blast, but do avail yourself of the leisurely pleasure of meteor watching and the possibility of seeing pieces of a comet that rounds the sun only every 415 years. Find a spot where artificial lights is at a minimum, dress warmly and head out around 3:30 a.m. Monday. Set up a comfortable lawn chair and have tea or coffee and a blanket at the ready. You’ll do well to face south or east. Now recline back to allow a fulsome view of the sky above and wait for a few well-deserved ooohs and aaahs.
Impactors strike during the reign of the dinosaurs (image credit: MasPix/devianart)
The recent meteor explosion over Chelyabinsk brought to the forefront a topic that has worried astronomers for years, namely that an impactor from space could cause widespread human fatalities. Indeed, the thousand+ injured recently in Russia was a wake-up call. Should humanity be worried about impactors? “Hell yes!” replied astronomer Neil deGrasse Tyson to CNN’s F. Zakharia .
The geological and biological records attest to the fact that some impactors have played a major role in altering the evolution of life on Earth, particularly when the underlying terrestrial material at the impact site contains large amounts of carbonates and sulphates. The dating of certain large impact craters (50 km and greater) found on Earth have matched events such as the extinction of the Dinosaurs (Hildebrand 1993, however see also G. Keller’s alternative hypothesis). Ironically, one could argue that humanity owes its emergence in part to the impactor that killed the Dinosaurs.
More than a dozen known impactors created 50 km sized craters (and larger) on Earth. One such example is the Manicouagan crater in Quebec, Canada. The crater is 215 million years old, and exhibits an 85 km diameter (image credit: NASA).
Only rather recently did scientists begin to widely acknowledge that sizable impactors from space strike Earth.
“It was extremely important in that first intellectual step to recognize that, yes, indeed, very large objects do fall out of the sky and make holes in the ground,” said Eugene Shoemaker. Shoemaker was a co-discoverer of Shoemaker-Levy 9, which was a fragmented comet that hit Jupiter in 1994 (see video below).
Hildebrand 1993 likewise noted that, “the hypothesis that catastrophic impacts cause mass extinctions has been unpopular with many geologists … some geologists still regard the existence of ~140 known impact craters on the Earth as unproven despite compelling evidence to the contrary.”
Beyond the asteroid that struck Mexico 65 million years ago and helped end the reign of the dinosaurs, there are numerous lesser-known terrestrial impactors that also appear destructive given their size. For example, at least three sizable impactors struck Earth ~35 million years ago, one of which left a 90 km crater in Siberia (Popigai). At least two large impactors occurred near the Jurassic-Cretaceous boundary (Morokweng and Mjolnir), and the latter may have been the catalyst for a tsunami that dwarfed the recent event in Japan (see also the simulation for the tsunami generated by the Chicxulub impactor below).
Glimsdal et al. 2007 note, “it is clear that both the geological consequences and the tsunami of an impact of a large asteroid are orders off magnitude larger than those of even the largest earthquakes recorded.”
However, in the CNN interview Neil deGrasse Tyson remarked that we’ll presumably identify the larger impactors ahead of time, giving humanity the opportunity to enact a plan to (hopefully) deal with the matter. Yet he added that often we’re unable to identify smaller objects in advance, and that is problematic. The meteor that exploded over the Urals a few weeks ago is an example.
In recent human history the Tunguska event, and the asteroid that recently exploded over Chelyabinsk, are reminders of the havoc that even smaller-sized objects can cause. The Tunguska event is presumed to be a meteor that exploded in 1908 over a remote forested area in Siberia, and was sufficiently powerful to topple millions of trees (see image below). Had the event occurred over a city it may have caused numerous fatalities.
Mark Boslough, a scientist who studied Tunguska noted, “That such a small object can do this kind of destruction suggests that smaller asteroids are something to consider … such collisions are not as improbable as we believed. We should be making more efforts at detecting the smaller ones than we have till now.”
Neil deGrasse Tyson hinted that humanity was rather lucky that the recent Russian fireball exploded about 20 miles up in the atmosphere, as its energy content was about 30 times larger than the Hiroshima explosion. It should be noted that the potential negative outcome from smaller impactors increases in concert with an increasing human population.
In 1908 the Tunguska impactor toppled millions of trees in a rather remote part of Siberia (image credit: Kulik). Had the object exploded over a city, the effects may have been catastrophic.
So how often do large bodies strike Earth, and is the next catastrophic impactor eminent? Do such events happen on a periodic basis? Scientists have been debating those questions and no consensus has emerged. Certain researchers advocate that large impactors (leaving craters greater than 35 km) strike Earth with a period of approximately 26-35 million years.
The putative periodicity (i.e., the Shiva hypothesis) is often linked to the Sun’s vertical oscillations through the plane of the Milky Way as it revolves around the Galaxy, although that scenario is likewise debated (as is many of the assertions put forth in this article). The Sun’s motion through the denser part of the Galactic plane is believed to trigger a comet shower from the Oort Cloud. The Oort Cloud is theorized to be a halo of loosely-bound comets that encompasses the periphery of the Solar System. Essentially, there exists a main belt of asteroids between Mars and Jupiter, a belt of comets and icy bodies located beyond Neptune called the Kuiper belt, and then the Oort Cloud. A lower-mass companion to the Sun was likewise considered as a perturbing source of Oort Cloud comets (“The Nemesis Affair” by D. Raup).
A halo of comets designated the Oort Cloud is theorized to encircle the periphery of the Solar System, and reputedly acts as a reservoir for objects that may become terrestrial impactors (image credit: NASA/JPL).
The aforementioned theory pertains principally to periodic comets showers, however, what mechanism can explain how asteroids exit their otherwise benign orbits in the belt and enter the inner solar system as Earth-crossers? One potential (stochastic) scenario is that asteroids are ejected from the belt via interactions with the planets through orbital resonances. Evidence for that scenario is present in the image below, which shows that regions in the belt coincident with certain resonances are nearly depleted of asteroids. A similar trend is seen in the distribution of icy bodies in the Kuiper belt, where Neptune (rather than say Mars or Jupiter) may be the principal scattering body. Note that even asteroids/comets not initially near a resonance can migrate into one by various means (e.g., the Yarkovsky effect).
Indeed, if an asteroid in the belt were to breakup (e.g., collision) near a resonance, it would send numerous projectiles streaming into the inner solar system. That may help partly explain the potential presence of asteroid showers (e.g., the Boltysh and Chicxulub craters both date to near 65 million years ago). In 2007, a team argued that the asteroid which helped end the reign of the Dinosaurs 65 million years ago entered an Earth-crossing orbit via resonances. Furthermore, they noted that asteroid 298 Baptistina is a fragment of that Dinosaur exterminator, and it can be viewed in the present orbiting ~2 AU from the Sun. The team’s specific assertions are being debated, however perhaps more importantly: the underlying transport mechanism that delivers asteroids from the belt into Earth-crossing orbits appears well-supported by the evidence.
A histogram featuring the number of asteroids as a function of their average distance from the Sun. Regions depleted of asteroids are often coincident with orbital resonances, the latter being a mechanism by which objects in the belt can be scattered into enter Earth-crossing orbits (image credit: Alan Chamberlain, JPL/Caltech).
Thus it appears that the terrestrial impact record may be tied to periodic and random phenomena, and comet/asteroid showers can stem from both. However, reconstructing that terrestrial impact record is rather difficult as Earth is geologically active (by comparison to the present Moon where craters from the past are typically well preserved). Thus smaller and older impactors are undersampled. The impact record is also incomplete since a sizable fraction of impactors strike the ocean. Nevertheless, an estimated frequency curve for terrestrial impacts as deduced by Rampino and Haggerty 1996 is reproduced below. Note that there is considerable uncertainty in such determinations, and the y-axis in the figure highlights the “Typical Impact Interval”.
Estimated frequency of impactors as a function of diameter, energy yield, and typical impact interval. Results assume an impact speed of 20 km/s and density of 3 g/cm^3 (image credit: Fig. 2 from Rampino and Haggerty 1996, NASA ADS/Springer).
In sum, as noted by Eugene Shoemaker, large objects do indeed fall out of the sky and cause damage. It is unclear when in the near or distant future humanity will be forced to rise to the challenge and counter an incoming larger impactor, or again deal with the consequences of a smaller impactor that went undetected and caused human injuries (the estimated probabilities aren’t reassuring given their uncertainty and what’s in jeopardy). Humanity’s technological progress and scientific research must continue unabated (and even accelerated), thereby affording us the tools to better tackle the described situation when it arises.
Is discussion of this topic fear mongering and alarmist in nature? The answer should be obvious given the fireball explosion that happened recently over the Ural mountains, the Tunguska event, and past impactors. Given the stakes excessive vigilance is warranted.
Fareed Zakharia’s discussion with Neil deGrasse Tyson is below.
“This shot is a composite of about 700 frames from a time-lapse I took in Big Sur, CA. I found 61 frames with meteors in them. (Some frames had two or three meteors.) Then I stacked the frames and created masks for each meteor. This is my final shot!” Credit: Ken Brandon.
“The Beacon: If you look closely you can see me looking up into the sky. Not a perfect shot but a lucky one. Credit to friend for firing the camera.” Credit: dwissman611 on Flickr.
Prolific astrophotographer John Chumack compiled this video of the Geminid Meteor Shower 2012, and in a minute and a half, shows over 400 meteors he captured on video!
Geminid meteor composite from 36 frames. Credit: Mark Ezell.
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Geminids at Gates Pass. Composite image from 30 frames of video. Credit: Sean Parker
The 2012 Geminid Meteor Shower has lived up to expectations, and here are some images and videos provided by people around the world.
“What an incredible show we had here!” said Sean Parker in Tucson, Arizona, USA. “I was able to see about 50 per hour.”
The images were shot at Gates Pass in Tucson, Arizona on the morning of 12-13-12. You can see M31 (Andromeda Galaxy 2.5 million light years away) at the left next to the Milky way.
More below, and you can click on most of these images to see larger versions in Flickr or Twitter.
Geminid Fireball. A large Geminid burns up in the atmosphere above the iconic Flatirons of Boulder, CO. Credit: Patrick Cullis
And another by Patrick:
Geminid Meteor Shower above the Flatirons, Boulder, CO. Credit: Patrick Cullis
Raining Down on Roseberry Topping (Geminid Meteor Shower 2012).Credit: Peter Greig.
Peter says: “This is the only meteor I caught whilst on a Geminid meteor hunting trip …at Captain Cooks Monument, Great Ayton, North Yorkshire, UK.”
Geminid Meteor Over Death Valley. Credit: Gavin Heffernan/SunChaser Pictures
Meteors in Malta. Credit: Leonard Ellul-Mercer
Leonard shares: “Last night the sky was totally overcast in Malta and this was very depressing as I was looking forward to this meteor shower. At around midnight I decided to retire, However, before doing so I went on the roof and noted some very small breaks in the cloud, but in a matter of 10 minutes I noted 6 bright meteors in these small gaps. So I presumed that there was a good meteor shower going on beyond those clouds. After about 30 mins. the cloud break increased and the show started off. It was a great meteor shower with bright meteors appearing every one or two minutes.”
Here’s a compilation of various views from a news station in Modesto, California. Some shots are obviously from a fish-eye camera:
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Winter Milky Way Geminids on December 12, 2012. Credit: John Chumack
The Geminid Meteor Shower is underway, with the peak on December 13th and 14th! SpaceWeather.com is reporting that international observers are counting as many as 50 meteors per hour as Earth plunges into a stream of debris from rock comet 3200 Phaethon. Astrophotographer John Chumack in Ohio, USA took the image of a bright fireball last night (Dec. 12/13) and said he was seeing one or two meteors every minute or so, describing the sky show as “definitely one of the best Geminid showers I’ve seen in over 20 years!”
John also compiled a video, below.
So if you’ve got clear skies, get out there and look up! The best time to look will be after dark on Thursday, December 13 and before dawn on Friday, December 14. The Geminids are notably one of the most reliable meteor showers, and this year the timing is great as the new Moon won’t intefer with the shower. Astronomers from McDonald Observatory at the University of Texas predicts skywatchers can expect to see dozens of meteors per hour.
Additionally, NASA says that for the first time, Earth might also pass through the tail of another object, comet Wirtanen, which could possibly provide even more meteors in the sky. No one is really sure what kind of meteor action this comet will produce, but Bill Cooke of NASA’s Meteoroid Environment off says even if the new shower is a dud, the Geminids should be great.
For the Geminids, meteors will appear to originate from the constellation Gemini, although they should be visible all over the sky. If Wirtanen does contribute to the shower, they may appear to come from the constellation Pisces.
If you’ve got cloudy skies or its too cold outside, there are a few alternatives:
You can follow along via Twitter and MeteorWatch. All you need to do is check for the #meteorwatch hashtag, and people will be posting descriptions and images.
You can also “listen” to the meteor shower: The Air Force Space Surveillance Radar is scanning the skies above Texas. When a meteor or satellite passes over the facility–ping!–there is an echo. Check out SpaceWeatherRadio for the broadcast.
