I just learned of the discovery of Comet ISON which has apparently electrified the astronomy world for months. What then caught my eye was a paper from David Eichler of Ben Gurion University published just two months later and curiously does not mention the newly discovered body.
Rather, Eichler investigated the effects of a comet the size of Hale-Bopp plunging into the sun. The result according to Eichler would be a huge solar disturbance which could perhaps explain the spike in radiocarbon at 775 AD.
ISON is apparently as large or larger than Hale-Bopp, and headed for a very, very close brush with the sun. I wonder what the probability is of Comet ISON actually plunging into the sun and resulting in an “Eichler Event?”
If it were high I would be forced to drop my regular aversion to forward catastrophism and admit the day was truly nigh.
I am also fascinated with the seemingly genetic relationship between the orbits of ISON and Newton’s Great Comet of 1680. From what I understand of comets, which is little compared to many Tusk readers, the orbital period should be relatively long because the motion of the object is relatively parabolic. I have seen mentioned that the orbital period of ISON should be something around 10,000 years (an interesting timescale to Tusk readers). But other articles seem to suggest that the Comet of 1680 and this comet may be separate pieces of a much larger body from the Orrt Cloud, sending chucks our way now and then. Instructive in its own way.
New Sunskirting Comet Could Provide Dazzling Display in 2013
2013 is looking to be a promising year for potential naked-eye comets, as a new comet has been discovered that will likely skirt close to the Sun, and could provide a stunning display late next year. The comet, named Comet C/2012 S1 (ISON), as it was discovered by a Russian team at the International Scientific Optical Network (ISON), is currently about the distance of Jupiter’s orbit. But it is projected to come within less than 2 million km from the Sun at perihelion by November 28, 2013. Ernesto Guido and Giovanni Sostero from the Remanzacco Observatory in Italy, along with their colleague Nick Howes from the UK have imaged the comet with the RAS telescope in New Mexico, and say, “According to its orbit, this comet might become a naked-eye object in the period November 2013 – January 2014. And it might reach a negative magnitude at the end of November 2013.”
A Mike Baillie fan passed along this fascinating discovery last week and I hoisted the paper to Scribd and the Tusk immediately. Mike is on to something mighty interesting. Nowhere has anyone noted the corellation between the two early Mayan “Baktun” transitions and spikes in ice core chemistry from Greenland.
Calendrical genius that he is, Mike even reverse engineers the data and finds the Mayan calendar — baring incredible coincidence – serves to memorialize the two events as well as perpetuate a useful chime for the future.
It is hard to grasp given his sparse abstract, but if I understand Mike Baillie correctly he infers that the Maya calendar writer long after the two extraordinary events divided his calendar so that the first event would mark the end of an inaugural cycle representing a number of days which — if repeated four more times — would coincide with the 2nd event. These five cycles were then followed in the calendar by an additional eight cycles of equal periods reaching to our own time.
It would be as if you were amazed at the appearance of Santa Claus, began counting the days since you saw him, was startled by his return, and later decided these visits were so significant that your calendar itself should be divided so as to determine good times to look out for the jolly old fellow. He may or may not come — but it is the right time to look.
How amazing. Mike has used well-scrubbed, expensive, empirical data from the end of the earth to place one of the silliest cultural phenomena of modern times into a rational, objective context. I would be less startled by a hi-res photo of the elf himself. Stay tuned…
I am not surprised. This is an absolutely fascinating subject and normal people are roaming around reading all sorts of things without the filter of someone else at the keyboard.
What makes Carlson’s broadly named journal article interesting is that it is clearly concerned with the Younger Dryas Boundary Hypothesis. He expresses a desire to test it more closely by appropriately examining existing ice records for chemical signals of the event, refering frequently to another objective overview from Melott which I am trying to post as well.
Note Carlson’s paper was written after Surovell et al had supposedly dumped the last shovel of dirt on the body of the hypothesis. It is hard to keep a good theory down these days.
[UPDATE]
I can’t find a handy Melott paper, but here is good article on the publication just before Sid Perkins turned his back on the subject of the Younger Dryas Boudary:
By Sid Perkins
Web edition: March 30, 2010
A+ A- Text Size
A new study cites spikes of ammonium in Greenland ice cores as evidence for a giant comet impact at the end of the last ice age, and suggests that the collision may have caused a brief, final cold snap before the climate warmed up for good.
In the April Geology, researchers describe finding chemical similarities in the cores between a layer corresponding to 1908, when a 50,000-metric-ton extraterrestrial object exploded over Tunguska, Siberia, and a deeper stratum dating to 12,900 years ago. They argue that the similarity is evidence that an object weighing as much as 50 billion metric tons triggered the Younger Dryas, a millennium-long cold spell that began just as the ice age was loosening its grip (SN: 6/2/07, p. 339).
Precipitation that fell on Greenland during the winter after Tunguska contains a strong, sharp spike in ammonium ions that can’t be explained by other sources such as wildfires sparked by the fiery explosion, says study coauthor Adrian Melott, a physicist of the University of Kansas in Lawrence.
The presence of ammonium suggests that the Tunguska object was most likely a comet, rather than asteroids or meteoroids, Melott says. Any object slung into the Earth’s atmosphere from space typically moves fast enough to heat the surrounding air to about 100,000° Celsius, says Melott, so hot the nitrogen in the air splits and links up with oxygen to form nitrates. And indeed, nitrates are found in snow around the Tunguska blast. But ammonium, found along with the nitrates, contains hydrogen that most likely came from an incoming object rich in water — like an icy comet.
More than a century after the impact, scientists are still debating what kind of object blew up over Tunguska in 1908. They also disagree about whether an impact or some other climate event caused the Younger Dryas at the end of the ice age. But the presence of ammonium in Greenland ice cores at both times is accepted.
“There’s a remarkable peak of ammonium ions in ice cores from Greenland at the beginning of the Younger Dryas,” comments Paul Mayewski, a glaciologist at the University of Maine in Orono who was not involved in the new study. The new findings are “a compelling argument that a major extraterrestrial impact occurred then,” he notes.
Whenever a comet strikes Earth’s atmosphere, it leaves behind a fingerprint of ammonium, the researchers propose. Immense heat and pressure in the shock wave spark the creation of ammonia, or NH3, from nitrogen in the air and hydrogen in the comet. Some of the ammonium, or NH4+, ions generated during subsequent reactions fall back to Earth in snow and are preserved in ice cores, where they linger as signs of the cataclysmic event.
Although an impact big enough to trigger the Younger Dryas would have generated around a million times more atmospheric ammonia than the Tunguska blast did, the concentrations of ammonium ions in the Greenland ice of that age aren’t high enough.
But the relative dearth of ammonium in the ice might simply be a result of how the ice cores were sampled, Melott and his colleagues contend. Samples taken from those ice cores are spaced, on average, about 3.5 years apart, and ammonia could have been cleansed from the atmosphere so quickly that most of the sharp spike might fall between samples.
COMMENT
CITATIONS
Melott, A.L., et al. 2010. Cometary airbursts and atmospheric chemistry: Tunguska and a candidate Younger Dryas event. Geology 38(Apr.):355. DOI: 10.1130/G30508.1
Abstract available at [Go to]
1Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045, USA
2Department of Physics and Astronomy, Washburn University, Topeka, Kansas 66621, USA
3Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA
Abstract
We find agreement between models of atmospheric chemistry changes from ionization for the A.D. 1908 Tunguska (Siberia region, Russia) airburst event and nitrate enhancement in Greenland Ice Sheet Project 2 (GISP2H and GISP2) ice cores, plus an unexplained ammonium spike. We then consider a candidate cometary impact at the Younger Dryas onset (YD). The large estimated NOx production and O3 depletion are beyond accurate extrapolation, but the ice core peak is much lower, possibly because of insufficient sampling resolution. Ammonium and nitrate spikes in both Greenland Ice Core Project (GRIP) and GISP2 ice cores have been attributed to biomass burning at the onset of the YD. A similar result is well resolved in Tunguska ice core data, but that forest fire was far too small to account for this. Direct input of ammonia from a comet into the atmosphere is adequate for YD ice core data, but not for the Tunguska data. An analog of the Haber process with hydrogen contributed by cometary or surface water, atmospheric nitrogen, high pressures, and possibly catalytic iron from a comet could in principle produce ammonia, accounting for the peaks in both data sets.
Nice blurb in Natural History Magazine this month. Still not sure if there is a longer article behind it in the print or on-line editions. Perhaps not, which would be a shame because Natural History is a fine magazine. It was one of those magazines you could buy when there were still bookstores where you browsed them. Since that is over in our neighborhood these days, with the closing of the Barnes and Noble, I guess I should subscribe if I want one on my coffee table under the Tusk.
A Real-Life Armageddon?
About 12,900 years ago, as Earth was warming up after the latest ice age, the globe abruptly entered an unusually cold 1,300-year spell, the Younger Dryas. The cause of the cooling, however, remained unclear. Now, Richard B. Firestone, a nuclear chemist at Lawrence Berkeley National Laboratory, and seventeen colleagues are bolstering the controversial theory that a cataclysmic event is to blame.
Using samples from eighteen sites on three continents, the researchers examined sediment sequences from the base of the Younger Dryas deposits, marking the onset of the cold period. Those lower-boundary sediments are a carbon-rich layer of earth, known as the “black mat.” All samples displayed abundant iron- and silica-rich microspherules, structures that are markers of a cosmic impact.
More important, melted glass matching the microspherules geochemically was found in samples from Pennsylvania and South Carolina and from Abu Hureyra, an archaeological site in Syria. For that material to form, sand-melting temperatures in the neighborhood of 3,600 degrees Fahrenheit are needed. “There are no forest fires or normal occurrences that create these kinds of temperatures,” says Firestone, who led the team that first raised the hypothesis of a cosmic bombardment by fragments of an asteroid or comet. In further support of the catastrophic event, the dated geological samples were compared with samples from a known impact site, the Meteor Crater in Arizona, and from the 1945 Trinity atomic bomb test site in New Mexico. Those two high-energy events produced geochemical products that were similar to those found in the Dryas samples.
Supporters of a Younger Dryas extraterrestrial impact explanation still have some work to do before the theory becomes widely accepted, Firestone notes. Perhaps the greatest challenge is to identify impact craters of suitable age left by space rocks raining ruin on multiple continents. Let the hunt begin! (PNAS)
They are still cleaning up the dropped jaws at Charlotte GSA. (Because of the formatting the poster is best viewed by clicking “download” in the upper left and viewing the file itself.)
E.P. Grondine was kind to contact me this morning with a thoughtful “Is everything OK?” query. Emphatically yes, and that is the problem. My business and civic life, as balanced with young family, have been all consuming for me of late. Our company just signed a very, very large contract and I have recently been appointed Vice Chair of the newly formed North Carolina Mining and Energy Commission, charged with the writing an entire set of on-shore exploration and production regulations for our state – from scratch — over the next eighteen months. Throw that in with a griping election season (recall I am a politico), and no particularly interesting news on the catastrophism front, and the wind just got sucked out of my hobby: the Tusk.
But none of that is really an excuse for ignoring a subject of existential importance for two months with nary a word. If we were blogging on “flowers” or “pets” that would be one thing….
What I need to do is pick through the last few papers, find some interesting and under recognized aspects (since no one really reads papers), and give them some play. Hmmm…. I will also take nominations along those lines (or other truly compelling subject matter).
I hate being dragged into these “modern” reports, since the Tusk specializes about this kind of stuff in the ancient past. But the UK event yesterday was really, really cool and I have posted before on these slow greenish fireballs.
Because of the unusually long duration and slow movement, some people have suggested the possibility of a satellite reentry. For various reasons, this is however very unlikely.
Multiple reports make clear the object was moving from east to west. A report of observers from Bussloo Observatory, the Netherlands, for examples states that the fireball appeared in the north, moving from Perseus to Bootes, almost horizontally from east to west. Similar reports (e.g. hereand here) come from Ireland.
Almost all non-polar satellites move prograde, from west to east (or north-southand v.v. for a polar orbit). An east to west movement would necessitate the object to have a retrograde orbit (meaning that it moves counter to the earth’s direction of rotation). Such objects are extremely rare: they literally amount to only a handful of objects (including the US FIA Radar satellites, and the Israeli Ofeq/Shavit satellites/rb). For this reason, it is extremely unlikely that this fireball was a reentering satellite. — sattrackcam.blogspot.nl
Despite my early understanding of the sloppy work of the authors, however, I did not have the data or original research at that time to do much about my frustration. The word had gone out quickly after the publication that the Surovell study was flawed. But appeals to properly follow lab protocols, the root of the matter, are simply not compelling when made by pajama bloggers. You can imagine then my soul-settling reaction following this week’s publication of LeCompte et al.’s, “Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis.”
At the time of the Surovell-Holliday publication their paper was considered a credible effort to replicate the measurement of the relative abundance of tiny “microspherules,” as separatedby Firestone from the magnetic fraction of sediment taken from points along the vertical walls of various well-dated archaeological sites.
Electron microscopy from LeCompte, Surovell-Holliday’s work was entirely optical
Two years earlier in 2007 the YDB team authors had shocked the scientific world by publishing evidence that simlar sampling had revealed a dramatic peak of microscopic spheres in the stratigraphy representing the onset of the Younger Dryas, a critical period always worth googling. These peaks and similar peaks in other materials suggested to Firestone that the spherules were the molten and quenched, largely terrestrial ejecta, following a catastrophic cosmic event, in many ways like the K-T event that brought an end to the era of dinosaurs.
It is not surprising that Surovell and Holliday, well published and respected archeologists who built careers studying Paleo-America, stepped up in 2009 to replicate or refute Firestone. What is surprising is the sloppy, unprofessional work which ensued in their names — and the ignorance and rank condescension which characterized their conduct going forward.
Surovell and Holliday did not find any spherules at any of the sites they and Firestone tested. And of the sites they tested independently, only one location yielded any spherules at all. So the study was bloody water to the skeptics and fence sitters circling since the 2007 introduction of the theory. A variety of characters, many with academic reputations at stake, had been cautiously waiting for the first chance to bury the living. Which they proceeded to do.
But, as referenced earlier, it was quickly apparent to the original authors — and thank goodness others — what had happened. Surovell-Holliday had failed in several ways to follow the testing protocol provided by Firestone for follow-up researchers. LeCompte documents six serious “Deficiencies” of the Holliday-Surovell study.
LeCompte emphasizes the importance of following the original protocol for “size-sorting” the little bits of material which have been previously separated from the archeological sediment. Size-sorting is a simple to understand but tedious process. The Firestone authors called for passing the grains through a sieve which excludes any grains >150 microns. Surovell-Holliday missed this simple prescription and passed the material through a sieve nearly ten times times more accommodating — a 1 mm mesh. (LeCompte later found the best results using 50 micron mesh).
Page 6, LeCompte, 2012
While there were five other serious deficiencies, size sorting was a fatal flaw. Indeed, LeCompte et al. made the same mistake early on, and also came up empty-handed:
Page 7, LeCompte, 2012
“Surovell’s work was in vain because he didn’t replicate the protocol. We missed it too at first. It seems easy, but unless you follow the protocol rigorously, you will fail to detect these spherules. There are so many factors that can disrupt the process. Where Surovell found no spherules, we found hundreds to thousands,” said Malcolm LeCompte, lead author of the new study, who is professor at Elizabeth City State University. — ‘Big Freeze’ nearly 13,000 years ago caused by comet explosion over Canada, Yahoo News, Sep. 19, 2012
The upshot is that when you sort out the largest of the material the peaks are noted in the finer particles, and the finer the better. Unless you sort down to a properly small size, your sample — and the task of picking through the chaff for the wheat — is greatly burdened by the many thousands of additional non-diagnostic larger particles you have collected.
If you are looking for tennis balls — it wise to remove the basketballs — particularly when there are orders of magnitude more basketballs.
When this and other equally serious shortcomings became apparent shortly after publication, there was some hope among the original authors that respectfully pointing out the deficiencies at a forthcoming meeting of AMQUA in Laramie, Wyoming might bring to light the proper methods and encourage some reappraisal of the results by Holliday and Surovell.
Only if it were so.
I accompanied Drs. Kennett, West and others to Laramie in 2010 with hopes of a fair-minded exchange of information and perhaps collaboration. What I found, frankly, was an atmosphere seething with a petty mix of intellectual cowardice and academic condescension that committed me more deeply to my new blog – and chills me to this day.
Dr. Holliday could barely contain himself during Allen West’s respectful and guileless presentation of the deficiencies, hurrrumphed his way through the talk, and refused to engage in a sincere Q & A afterwards. It was as if Holliday were channeling fabled charmer Aleš Hrdlicka in a final tour of the American West. His cynicism was largely reflected by the crowd, whose cliquish nature — including furtive huddles and giggles in the halls — was more in keeping with Mean Girls than Socratic dialogue.
Surovell’s reaction was most disappointing when recalled today after three years. As with all conferences there was plenty of opportunity to gauge reaction during the inevitable sidebars and auditorium chatter. West’s critique had clearly affected Todd. I will not commit my memory to his exact words here, but I will never forget his physical bearing and his message afterwards. Todd hung his head, groaned deeply, and said he simply did not have the time to do the work again correctly, tedious as it is.
Naif that the Tusk is, I thought Todd meant he had no time available right now — and that he would get to it in time. I understand now, three years later, after 26 citations of the flawed article, and thousands of repetitions of it’s intellectually destructive message, that Todd meant he would never have time to correct his mistake. Not in the next issue of PNAS, not at the next meeting of AMQUA — he meant never.
That keeps me writing.
Counter-criticism aside, outsiders are walking away from the mammoth-killer impact in increasing numbers. “I spent 16 months in the lab and found very little evidence to support their hypothesis,” says Surovell. “I have other things to worry about.” – Nature, August 30, 2010
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