Decoding the heavens is published today

6. November 2008 17:28

Just a short post to say that Decoding the Heavens, my book about the Antikythera mechanism, is published in the UK today! It has had some great reviews so far, including in BBC Focus magazine, who likened it to "a dynastic saga, complete with jealous rivals, personal tragedies and lifelong obsessions" (not online unfortunately); Nature, who described it as "a gripping and varied account"; and Scotland on Sunday, who wanted more pictures (though there are already quite a few) but judged the book itself as "informative and thoroughly researched".

There's a lot of online interest as well. ScienceCulture bulletin recommends Decoding the Heavens, calling it "a wonderful tale"; Popular Science has given it five stars, describing it as "an entrancing book"; while New Scientist says it is "sprinkled with the magic dust of an Indiana Jones adventure".

Decoding the Heavens is due out in the US at the end of January 2009, and is already being translated into several languages including Japanese, Greek and Polish.

I'm off for a celebratory beer...


Bring back the mammoth

5. November 2008 08:38

All over the web today is the story that scientists have cloned mice from animals that had been frozen for more than a decade. The work raises the possibility of cloning extinct species - such as woolly mammoths preserved in the permafrost. This picture shows one candidate - a perfectly preserved baby mammoth found last year, after it had lain frozen in Siberian permafrost for 10,000 years.

I'm a biologist by training and I'm fascinated by what genetic material can tell us about the past (hence the post on Ötzi the ice man last week). Researchers have already managed to resurrect extinct virus strains - most dramatically in 2005 they recreated the deadly 1918 flu virus from the cells of a flu victim preserved in Alaskan permafrost. 

But to clone an animal you usually need living cells, whereas freezing kills cells because of the ice crystals that form. In this latest work, Teruhiko Wakayama and her colleagues from the RIKEN Center for Developmental Biology in Kobe, Japan, got round the fact that cells in the frozen mice had ruptured by extracting only the cell nuclei, which contain almost all of an animal's DNA, and using that for the cloning process.

The mice Wakayama used were frozen at -20 C (roughly the temperature of permafrost, or a kitchen freezer) for 16 years, without any protective chemicals. The fact that it worked means cloning other animals that have been frozen for longer periods might not be so far-fetched after all - DNA is pretty stable at low temperatures. Doing this for ancient species such as mammoths is still a stretch though because the DNA will degrade slowly over time, especially if the ground they're in has ever defrosted and refrozen.

Of course creating a clone would only be the start of biologists' problems - they'd need living relatives for the clone to breed with, and they'd have to find somewhere for it to live (tricky for mammoths, as all the permafrost is melting!) But I still think there's something magical about the possibility of seeing an ancient animal brought back to life, even if it's not such a great idea in practice.

Pic: Photoshot


The real Babylon

4. November 2008 09:21

The name "Babylon" has to be one of the most evocative from history, but what was the city really like? 

Next week an exhibition is opening at the British Museum in London, that aims to bring this ancient city back to life again. It's called Babylon: Myth and Reality, and it runs from 13 November to 15 March. The real Babylon, according to the exhibition overview, was "an imperial capital, a great centre of science, art and commerce".

Events like this are often frustrating because although they are full of beautiful art exhibits, the science and technology of ancient cultures is under-represented. At the same time, museums that specialise in science and tech don't tend to have much to say about the ancient world.

Babylonian priests were among the most accomplished astronomers of their time. They believed that the movements of the Sun, Moon and planets were omens (generally bad ones) about the fate of the King and his country. Lunar and solar eclipses were especially significant. Here's a sample prediction from a list of omens called Enuma Anu Enlil: "When in the month Ajaru, during the evening watch, the moon eclipses, the king will die. The sons of the king will vie for the throne of their father, but will not sit on it."

Generations of priests watched the skies round the clock, and noted down everything they saw on clay tablets, so that the appropriate rituals could be carried out to avert whatever bad thing was going to happen. If an eclipse was predicted, for example, the king could abdicate temporarily, and grab a beggar off the street to sit on the throne in his place until the eclipse had passed.

Lunar eclipse

A lunar eclipse Luc Viatour

By the sixth century BC, the Babylonians could recognise regular cycles in the movements of celestial bodies. They didn't have any sense of geometrical orbits - events in the sky might as well have been a light show taking place on a flat screen - but they could use arithmetical methods to predict in advance what was going to happen. They knew that the Sun and Moon's relative motions repeat after 19 years for example (because there are almost exactly 235 lunar months in 19 solar years) and that eclipses repeat after an 18-year cycle.

Intriguingly, both of these cycles are found in the Antikythera mechanism, showing that Greek astronomers were heavily influenced by the Babylonians at the time. The eclipse data may have been brought back to Greece by an astronomer called Hipparchus, who worked on Rhodes in the second century BC. He had lists of Babylonian observations going back centuries - one theory is that he must have visited Babylon himself, and worked with a scribe there to extract the data he needed.

By this time, Babylon (in what is now southern Iraq) was an empty city. Alexander the Great had taken over the region in the fourth century BC, and his successor Seleucus moved all the inhabitants to a new capital, Seleucus (of course) on the river Tigris. But a small band of priests had refused to leave and were still there in Hipparchus's time, observing the skies and carrying out their rituals in the empty temple.

I asked the British Museum if any of this would be represented in the exhibition and although the Babylonians' interest in astronomy will be mentioned, there won't be any related exhibits. There is an associated website for schools, however, which includes a section on Babylonian astronomy (among other things you can explore a mini-library of carved tablets, along with their astronomical translations). And John Steele of Durham University, who probably knows more about ancient eclipse prediction than anyone, is giving a talk about Babylonian astronomy and astrology at the museum on December 4.


Latest film on Antikythera mechanism

2. November 2008 19:51

A few days ago, the Archaeology Channel published a 14-minute video documentary about the Antikythera mechanism, featuring filmmaker Tony Freeth. It was originally posted on Nature's website in July, but if you haven't already seen it, it's well worth a look.

It's a beautifully made short film, and it includes footage of the project to image the Antikythera fragments in Athens in autumn 2005 (see pic). There are also some gorgeous X-ray images of details hidden inside the fragments, and a computer animation of the mechanism's internal workings.

This film was made to accompany the publication of Freeth's second Nature paper on the mechanism, which reported a preliminary reading of some of the inscriptions on its dials. This revealed that one of the dials kept track of the locations of the Panhellenic games, including the Olympic games, and that the device's calendar used local month names that may have come from Syracuse in Sicily. (There was also some new information about the eclipse prediction dial, but that's for another post.) You need a Nature subscription to read the paper itself but there's a lot of interesting data in the supplementary information, which is free. 

Freeth and his colleagues, including Alexander Jones at the Institute for the Study of the Ancient World in New York, are now preparing a more extensive report on the inscriptions, though it'll probably be a while before this is ready. As well as providing clues to the Antikythera mechanism's place of origin, the researchers hope that the inscriptions can also be used to date it more precisely.

The ship on which the mechanism was found probably sank in the 60s BC, but what we don't know is how old the machine was when the ship went down. An epigrapher called Professor Benjamin Merritt who worked at the Institute for Advanced Study in Princeton studied its inscriptions in the 1970s, and concluded that they date from the first century BC, suggesting the mechanism was quite new when the ship sank. But Haralambos Kritzas, Director Emeritus of the Epigraphic Museum in Athens, recently dated them slightly earlier, around 150-100 BC. 

Jones is looking for other inscriptions dating from around this time, to compare against the Antikythera inscriptions and hopefully pin down the date more tightly.

Imaging the Antikythera mechanism

This pic shows Pandelis Feleris, a conservator at the National Archaeological Museum in Athens, getting the main fragment of the Antikythera mechanism ready for imaging by X-Tek's "BladeRunner" microfocus X-ray machine in November 2005 (thanks to X-Tek's Roger Hadland for the photo).


Archimedes goes green

1. November 2008 10:35

The Daily Mail just ran a nice story saying that one of Archimedes' best known inventions is being adapted to produce green electricity.

The "Archimedes screw" consists of a screw inside an angled tube - as the screw turns, it lifts water up through the tube (see pic below). The mathematician, who worked in Syracuse, Sicily, in the third century BC, is supposed to have invented it to drain water from the hulls of ships, and it is still one of the most efficient ways we know of transferring large volumes of water. The screws are still widely used, from low-tech crop irrigation in regions such as Egypt's Nile Delta, to state-of-the-art flood defence schemes.

Green engineers have now reversed the principle for use in a small hydroelectric plant in the Yorkshire Dales. Water flowing through the River Wharfe will fall down two Archimedes screws, turning the screws and driving turbines. Hydroelectric dams are usually huge multimillion pound projects that require powerful flows of water. But this set-up should allow electricity to be generated from rivers on a much smaller scale. According to the Mail, the two 12-metre-long screws will generate 510,000 kilowatt hours of green electricity per year, enough to power 100 houses.

Also in the news last week was an even more futuristic use for the Archimedes screw. Discovery News reported that scientists are aiming to use the principle to create a replacement human heart. Instead of building a heart that beats, a pump based on an Archimedes screw would drive blood around the body at a constant rate. Such pumps are already used to help out weak hearts, and have been implanted in more than 1600 patients since 2003. But researchers from the Texas Heart Institute and the University of Houston now plan to use the technique to replace failing hearts completely. It'll take many years of studies before they're ready to do it though, not least to work out whether there are any long-term adverse effects of not having a pulse.

By the way, the Archimedes screw should not be confused with another of the great man's inventions, the "endless screw" (yes that really is its name). In this gadget, a threaded screw is used to engage a toothed wheel with a much larger gear ratio, meaning that a lot of gentle winding turns the wheel a small distance, but with a much stronger force than that originally applied by the winder. According to the ancient historian Plutarch, such a device allowed Archimedes to impress Syracuse's king by single-handedly dragging a ship over the ground, "as smoothly and evenly as if she had been in the sea".

This sounds like a bit of an exaggeration - Plutarch was writing a few hundred years later after all. But the fact that Archimedes was playing around with gearwheels and force ratios add support to the idea that he might have been the first person to develop mathematical gearwork of the type used in the Antikythera mechanism.


Antikythera art

31. October 2008 09:01
Antikythera main fragment
I thought I'd do my bit for the arts today by flagging up some of the various creative projects inspired by the Antikythera mechanism.
First, there's poetry from a site called The Starlite Cafe. Scroll down for the poem... be warned, some of the rhymes are very dodgy, but it's quite sweet. 
Then there's art. My favourite so far is that of Morgaine von Slatt. She says she's inspired by "antique scientific instruments, gears and old machinery and alchemy". The Antikythera artwork shown here uses one of the diagrams from a 1974 paper by a science historian called Derek de Solla Price (this was the culmination of his life's work on the mechanism). I don't think it's free online anywhere but you can see the original diagram here. For some reason von Slatt's interpretation reminds me of the tracks from the bubble chambers used by early particle accelerators. Beautiful.
And there are plenty of bands. Here are links to three:
The Antikythera Mechanism
Surprisingly good. It's "shoe gaze, alternative, post punk", apparently. The song I listened to reminded me of driving in the rain.
Black t-shirts, headbanging, lots of screaming. No idea what they're saying so apologies if any of it is inappropriate!
Antikythera Device
Acoustic guitars. Pudding bowl haircuts. Great use of Godzilla footage. Absolutely no singing.
Finally, there is even a scent inspired by the Antikythera mechanism. It includes teakwood, oak, black vanilla and tobacco, and apparently it gives you the sense being in a busy workshop of polished gears and polished wood...


Ötzi the ice man

30. October 2008 19:48
Otzi the ice man

Ancient mystery of the day: does Ötzi, a 5300-year-old human mummy found frozen in the European Alps in 1991, have any living descendants today?

Ötzi was fully defrosted in 2000, and since then, Franco Rollo of the University of Camerino, Italy, and his colleagues have been gleaning what they can from the mummy's DNA.

In 2002 we found out from DNA extracted from the contents of his gut that before Ötzi died he feasted on ibex goat and vegetables, followed by red deer and possibly some grains. This carnivorous diet, along with an arrow head found in his shoulder, suggested that he was a hunter, killed by a hungry rival. DNA from pollen on Ötzi's clothes also showed that his last walk was through a coniferous wood.

Today, Rollo has published a paper in the journal Current Biology, in which he reports the full sequence of the DNA from Ötzi's mitochondria. These are tiny organelles inside cells which produce energy, and they have a few genes of their own. Mitochondria are only inherited through the maternal line, and their DNA is good for tracking ancestry over very long periods of time.

Rollo's team reports that Ötzi belonged to a lineage for which no survivors are known today, suggesting that his line probably went extinct.

But within hours of the announcement, a rival team said they had found the opposite. Alan Cooper, head of the University of Adelaide's Australian Centre for Ancient DNA and his colleagues have been working on their own analysis of the mummy's mitochondrial DNA, and have apparently found someone living today who is "very, very closely related" to Ötzi. They have submitted a paper for publication in a journal, so I guess we'll have to wait till it comes out to see the full details.


Archimedes online

29. October 2008 08:18
The StomachionI just heard that later today, all of the data from the Archimedes Palimpsest Project is being made freely available online.

I'm particularly interested in Archimedes because of his possible links to the Antikythera mechanism. He lived in Syracuse in the third century BC. That's too early for him to have made the device, which dates from around 100 BC, but he may have been the original inventor of this type of gadget. Ancient texts say he built a bronze model that showed the movements of the Sun, Moon and planets around the Earth. And the month names used on the mechanism's calendar may well have come from Syracuse. More on all this in my book of course!

Anyway, the Archimedes Palimpsest is one of the most important sources of information about the great mathematician's work. A palimpsest is a hidden text, created when Medieval scholars scraped the ink from old parchment so that they could use it again. Luckily for us, traces of the original words often remain. This palimpsest consists of seven of Archimedes' treatises, copied by a scribe in the tenth century, probably in Constantinople, and then written over with a prayer book in the 13th century.

For one of the treatises (On Floating Bodies), this is the only surviving copy in Greek. And for two others (The Method of Mechanical Theorems and the Stomachion) this is the only copy that survives at all.

The palimpsest came to light in 1906 but was then lost for much of the twentieth century. It turned up decades later and was sold at auction for $2.2 million on 29 October 1998, to a mysterious US collector known only as "Mr B". He deposited it at the Walters Art Museum in Baltimore, and has funded a project to conserve the parchment and image the lost writing.

Researchers have made Archimedes' words clear again by taking photos of the pages using lots of different wavelengths, then combining the images on a computer and manipulating them to highlight the Greek text while toning down the top layer of writing. Now, exactly ten years after the palimpsest was sold at auction, they're putting it all online.

Reviel Netz of Stanford University is one of the researchers who has been deciphering the text. He reckons the Method shows that Archimedes was using infinity in his calculations, something that the ancient Greeks weren't thought to have done. Meanwhile the Stomachion is the name of an ancient game in which a square was divided into 14 pieces according to a set pattern (see the pic). The name literally translates as "belly ache", presumably because of its difficulty. It wasn't clear what the game involved, but Netz thinks the idea was to work out how many different ways the 14 pieces could be put back together into a square (17,152 according to modern scholars). If so, it would mean that Archimedes was the founder of the field of combinatorics - the study of numbers of possible combinations.

If you want to know more, Netz, along with curator William Noel, has written a great book about the palimpsest called The Archimedes Codex. They reckon there's still plenty more information to be gleaned from the texts. And now that all the images are freely available, anyone can have a go at reading them.


Models of the Antikythera mechanism

28. October 2008 18:17
Michael Wright's model of the Antikythera mechanism

Hello, and welcome to my blog! My plan is to keep you updated about any new developments relating to the Antikythera mechanism - there is lots of research going on and plenty of questions still to be answered, so I'm sure there will be some surprises to come. In particular, scholars are still reading the inscriptions that covered the device, so I'll write here about the progress they make as I hear about it.

I'll also let you know when I add new material to this website, and I'll keep an eye out for any other interesting news relating to ancient history, and ancient science and technology in particular.

For my first post, I thought I'd let you know about some of the models that have been made of the Antikythera mechanism, as a collection of them has just been brought together for an exhibition in Athens. The exhibition opened at the Ionic Centre last week, and it runs until 14 December. Since 2006, when Nature published a high profile paper explaining how the mechanism would have worked, building models of it - real and virtual - seems to have become quite a popular pastime. The ones on show in Athens include a transparent device made by an Italian amateur astronomer and computer programmer called Massimo Vicentini and a less traditional interpretation from a Dutch engineer called Tatjana van Vark. 

But my favourite has to be the model made by Michael Wright, who worked for many years as a curator at the Science Museum in London. He has spent twenty years studying the Antikythera mechanism, and after X-raying the surviving fragments he built a beautiful working brass model. Unfortunately he doesn't have a website I can link to but here's a photo of the model, that Wright sent to me. I'm hoping to post a video of it soon. 

Several people have asked me if any Antikythera models are commercially available. As far as I know there are no plans for this yet, but with the interest that's out there I'm sure it's only a matter of time.