Comet Tempel 1 Re-Visited


Recently my mind has been blown twice. First by listening to the first four songs on Funkadelic’s acid-drenched 1970 album Free Your Mind And Your Ass Will Follow. Then by studying the above picture.

It’s comet Tempel 1. Up close in interplanetary space. And it’s been visited twice by different space probes: first Deep Impact imaged the comet on its way towards the sun in 2005 and shot an impactor point blank at it. Then the Stardust probe, originally designed and launched to meet with another comet, was sent to meet Tempel 1 on its way out again from the sun. Today Stardust imaged the comet and got a clean shot of the surface where the impactor hit 5½ Earth years ago. Science rules, Dear Reader, science rules.

For more Tempel 1 coverage, see Emily Lakdawalla’s blog at the Planetary Society.

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Mars Rover(s) Still Working After Seven Years


Dear Reader, remember the remote-controlled Mars rovers, Spirit and Opportunity? How long is it since the last time you thought of them? Spirit landed on Mars seven Earth calendar years ago today, Opportunity on 25 January — and at least Oppy still works fine! Spirit has sadly been stuck on the edge of a small dust-filled crater since May 2009, one set of wheels inside and one outside the crater. It is currently incommunicado because of the Martian winter, being in a poor position for solar power. But it still probably works. And Oppy trundles on toward Endeavour crater. Currently it’s taking stereo images at the 80-metre diameter Santa Maria crater. Check out the project’s web site for news!

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Chiemgau Impact Hypothesis is Dead

Update 13 December: Florian at Astrodictum Simplex has translated the whole entry into German. Thank you, Florian!

Update 21 December: German pop-sci web zine Scinexx reports on the poor status of the impact hypothesis and refers to this blog entry. They also mention a really weird idea of the CIRT’s that I hadn’t heard about: that the impact event somehow taught certain Celts to make better steel, and that this material eventually allowed the Roman empire to expand!

Back in August, I blogged about this dodgy paper that had been published in Antiquity. Subsequently, German geologists Robert Darga and Robert Huber and I got together and wrote a rebuttal, which we submitted to Antiquity. It got turned down for a pretty good reason: somebody else wrote a rebuttal featuring original results from the site in question that blows the whole idea of the original paper to bits. That work hasn’t been published yet, and the authors of the dodgy paper have been busy promoting their freaky ideas, so the two Roberts and I have decided to publish our paper here on Aard. The title pretty much says it all:

The Site of Phaëton’s Chariot Crash is Most Likely Illusory, as the Chiemgau Impact Hypothesis is Not Accepted by Geological Consensus.

Continue reading

Amateur Impact Hypothesis Makes It Into Major Archaeology Journal

ResearchBlogging.orgShortly after my buddy Jeff Medkeff died in 2008, a joint book review of ours was published in Skeptic Magazine. Here we criticised a book by Alan Bond and Mark Hempsell, two aeronautics engineers, where they claimed that a 7th century BC cuneiform tablet from Mesopotamia described an asteroid striking the Austrian Alps in 3123 BC. Their argument was in our opinion extremely speculative or pseudoscientific, regardless of whether you saw it from an astronomical, geological or archaeological point of view.

Bond & Hempsell self-published their book. But to my surprise, the summer issue of the prestigious archaeology quarterly Antiquity contains a paper on a similar topic. The head author is one Barbara Rappenglück who gives her affiliation as the Centre for Interdisciplinary Studies in Gilching, Bavaria (pop. 17 000).

Briefly, Rappenglück et al. argue that the Greek myth of Phaëton joy-riding and crashing the sun chariot records a meteorite strike in the Chiemgau region in Bavaria some time in the Bronze Age. In their opinion, details in the various versions of the story found in Greek and Roman literature all agree with the circumstances of that strike.

Rappenglück et al.’s case is stronger than Bond & Hempsell’s in that the written sources they appeal to are not difficult to understand on the level of basic language, and the myth of Phaeton is quite likely to have been in existence about the time of the alleged meteorite strike. Overall, they also present and discuss their evidence in a far more sober manner than Bond & Hempsell. It’s not a crazy paper. But nor do I find it convincing.

The authors’ pattern-seeking willingness to see every little detail of the texts as relevant to their case is a bad sign. And a serious problem with their interpretation is that in order for it to work, there must be some way for eyewitness accounts to have travelled from Bavaria to Greece, and to impress Greek poets enough that they put the matter into their mythology. Rappenglück et al. don’t even tell us from what direction the meteorite approached Bavaria. I think we can assume that it did not pass over Greece, or they would have made a point of informing us.

Large meteorite strikes are no laughing matter, and the Mediterranean area would in all likelihood have felt the climatic after-effects of an impact like the one alleged for Chiemgau. But to think that Greek story tellers would have connected the atmospheric dust and the series of poor harvests they experienced to wild tales of crashing fire balls from the sky told in proto-Celtic by refugees or traders from across the Alps – that’s just silly in my opinion.

Still, the main weakness of Rappenglück et al.’s work is one that it shares with Bond & Hempsell’s book. The latter could point to no impact crater at all. And the Chiemgau features are not accepted as impact craters by most professional geologists. The idea in fact originates with a group of amateur metal detectorists who formed a research group after finding odd metallic remains in 2000.

So Antiquity’s peer review has failed in this case. Rappenglück et al. say “These meteorite craters date from the Bronze Age, and we think they can explain a motif in Greek mythology”. But the reviewer (an archaeologist? a classicist?) doesn’t seem to have picked up on the fact that at this point in time, belief in those meteorite craters is a speculative minority position. And before geologists reach a consensus that the craters exist and are due to an impact (as seems unlikely right now), archaeologists and historians cannot use them to explain anything. Greek mythology certainly can’t be used to strengthen the impact hypothesis.

Atlanta area denizens, don’t miss the Charity Star Party in Jeff Medkeff’s memory on September 2! George Hrab and the hosts of the Astronomycast will be there. The proceeds will benefit the Leukemia and Lymphoma Society.

Barbara Rappenglück, Michael A. Rappenglück, Kord Ernstson, Werner Mayer, Andreas Neumair, Dirk Sudhaus, & Ioannis Liritzis (2010). The fall of Phaethon: a Greco-Roman geomyth preserves the memory of a meteorite impact in Bavaria (south-east Germany) Antiquity, 84, 428-439

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Monday Miscellany


Web gems have been sent my way.

  • ASPEX, makers of scanning electron microscopes, offer to scan your sample for free and post the image on their site. Finally you can learn about the micro-structure of your tear-duct sleep gunk!
  • Pablo Zalama Torres makes lovely replicas of archaeological pottery.
  • An amateur volunteering for the Stardust @ Home project has probably discovered “the first known sample of matter ever collected from the local interstellar medium”. Space dust!
  • James Randi has come out of the closet. Congratulations, Randi! Your houdinesque escape will make it easier for other gay skeptics in the future.

Distributed Sun-Staring


Human eyes and brains are still way, way better at image recognition than computers. There are many visual tasks that we do swiftly ourselves but that we can’t yet get machines to do reliably at all. In January of ’06 I blogged about the Stardust @ Home project where you can help identify particles of interplanetary dust and comet-tail debris in a huge library of digital micrographs. Now I’ve learned from the BBC’s Digital Planet podcast about Solar Stormwatch, where you can help forecast coronal mass ejections and other destructive solar activity that humanity needs early warning about. Check it out!

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Jungle-Covered Impact Crater


The Vichada river in Colombia is a tributary of the Orinoco. In 2004 part-time geologist Max Rocca discovered that it skirts South America’s largest impact crater. It measures 50 km in diameter, nearly a third of the Chicxulub crater caused by the space rock that killed off the non-avian dinos.

This image visualises two important things.

1. Our planet is just another crater-pocked space rock, though here surface erosion acts much faster than on nearby worlds, and we have plate tectonics, all obscuring the impact scars. The Vichada example is a recent one, being less than 30 million years old.

2. Geological time is looong. Look at that meandering river doing a little detour around the crater’s edge!

There’s a good feature piece on the Vichada crater at the Planetary Society’s web site.

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Mars Rovers Still Working After Six Years


Dear Reader, remember the remote-controlled Mars rovers, Spirit and Opportunity? How long is it since the last time you thought of them? Spirit landed on Mars six Earth calendar years ago today, Opportunity on 25 January — and both still work fine! Sadly, though, Spirit has been stuck on the edge of a small dust-filled crater since May last year, one set of wheels inside and one outside the crater. Its future looks dim as the Martian winter approaches and it is in a poor position for continued solar power. But Oppy trundles on toward Endeavour crater, taking pictures and analysing rocks. In July it found a huge iron-nickel meteorite sitting on the Martian ground surface. Check out the project’s web site for news!

Update 5 January: Check out this excellent overview from the Planetary Society of currently active missions in the solar system and launches planned for 2010.

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Don’t Miss the Geminids

Tonight the Geminid meteor shower peaks. My wife and I were out last night and saw loads, about one big fat shooting star a minute. Don’t miss the year’s best meteor shower! It’s because the Earth passes through the sandy exhaust trail of a comet. Tomorrow night will be good as well.