Decoding the 2,000-year-old Antikythera Mechanism

Good God, Stargate!

It took the best we have today to unlock the secrets of the best from 65 B.C.; imagine how many more devices like this have been lost to the world. Where would we have been had they stayed with us through all these centuries?

Editor's note: Andrew Ramsey is a computed tomography specialist with X-Tek, Trink, U.K., and was part of the team making 3-D CT scans of the Antikythera Mechanism last year. He's presenting at the Athens Conference, Thursday 29 November. As time, connectivity, and strength permit, he'll be emailing observations and comments from the Conference.

Yes, I'm a little nervous. There are far more people coming tomorrow than to the Press Conference in May [2006] at which, by the photos on the web, there were about 300 people. I've never spoken to so many people before. But then they're all really interested in our work so it should be fine. The only problem is that I've got so much to say and only 20 minutes to say it in.

We landed here tonight about 8.20pm and were picked up by Alex, a friend of the conference organiser, whom I met last October. He brought Roger Hadland, the owner of X-Tek, Martin Allen (from our east of England office) and myself, together with two "archaeoastronomers" (that's what they described themselves as) from Leicester University, and John Seiradakis, astronomy professor from from Thessaloniki University whom I met last year. At the hotel I met up with Tony Freeth, the freelance film-maker who organised the whole inspection, Professor Mike Edmunds, professor of astronomy at Cardiff University who is the lead academic in this project, and also Xenophon Moussas, the astronomy professor from Athens University, who became a firm friend when I and my girlfriend came to view the Total Solar Eclipse with him in March of this year. Also there was Tom Malzbender from HP (been up for 36 hours since flying from California tonday!), who did a lot of visual imaging of the fragments using a special dome (weblink from www.antikythera-mechanism.gr to their work here) and Michael Wright (and his wife Anne) who did some early X-ray imaging in 1990. I sat opposite Michael and it is obvious that he is more than a little frustrated that the latest work has eclipsed (pardon the pun) his earlier work before he has fully published - but then that was over 15 years ago! It's nice though that he is here and speaking tomorrow, as he has studied this Mechanism more than anyone else.

Joining us at the table in the restaurant tonight was Aubrey Manning, a BBC TV presenter who has done some great historical TV series. He is attending the conference tomorrow.

I'm really looking forward to the conference tomorrow and to hearing all the presentations.

The "Nature" paper is out now so the embargo on its content is lifted, so I can speak more freely. As a dedicated solar eclipse chaser myself I can understand the ancients' fascination with these phenomena, so to find out that this Mechanism's primary role was to predict both solar and lunar eclipses was a wonderful revelation. However, to realise that to do this accurately, they had to work out that the Moon revolved about the Earth in an elliptical orbit, at a variable speed, and to model this in the Mechanism is truly incredible. I, and the rest of the world's astronomers, always thought that Johannes Kepler discovered the elliptical motion of the planets in the 16th century, but here it is, carved out in bronze for us all to see in the CT data. The ancient Greek astronomer Hipparchus was believed by some to have come up with this hypothesis in the 2nd century BC, so to see it in reality is a truly remarkable find.

To quote Professor Mike Edmunds, of Cardiff University, the lead academic on this: "You think to yourself, 'Bloody hell, that's clever'!".

My presentation tomorrow is about the X-ray technology - that's the field my company X-Tek is in (www.xtekxray.com). I shall be talking about how we achieved such high resolution, and how we were able to see through many centimetres of bronze, as well as talking about the story of how we got an 8-ton X-ray system from the UK to Athens, Greece. I'll leave it to the others to describe what was found in the X-ray CT data.

More tomorrow. It's gone 1am now, so I'm off to bed.

Cheers,

Andrew.

Slide Show Broken - no images - any gallery?

Great article

We made both The Times and The Independent, the UK's major newspapers today:

http://news.independent.co.uk/world/science_technology/article2026794.ece and

http://www.timesonline.co.uk/article/0,,2-2478493,00.html . Apparently it took up a whole page in the Times.

Well, what a day!! What a long day! This has been the most amazing day of my career - except for the day I first read the hidden lettering in the Mechanism last October - I was the first person in 2000 years to read these inscriptions.

What a long day it's been! Lectures from 9am to 10pm. There must have been at least 200 attendees at the main scientific conference today. After an introduction by the led UK academic on the project, Mike Edmunds, professor of astrophysics introduced the Mechanism and two of the National Archaeological Museum creators explained the context in which it was found - the shipwreck in about 80BC off the coastof the island of Antikythera.

Then Tom Malzbender of Hewlett Packard - based in Silicon Valley - talked about the reflectance imaging technique they used. He spoke about how they can see the effect of lighting from different directions using their special light dome. From these images they can compute the surface normal and then re-render the resulting 3D surface as if it were highly reflective metal, thus making the text far easier to read.

Then it was my turn - you're right, I wasn't nervoous at all. I spoke about how our X-ray CT scanners differ from medical scanners in that they use a much smaller source of X-rays, so allowing geometric magnification to be used to show even more details, and how our much higher energy source (450kV) can see through so much metal. I think the presentation went well and I certainly got some great feedback on it.

Yanis Bitsakis of Athens University spoke about how the text had been decoded from the HP images and the X-ray CT images. It's a painstaking process.

Tony Freeth then gave an excellent summary in two lectures on the findings of the CT inspections. Let me summarise them. If you thought Kepler discovered the elliptical motion of the planets think again. This mechanism not only includes a device for converting the uniform motion from Full Moon to Full Moon into the irregular elliptical motion of the Moon against the stars due to its elliptical orbit, but it also includes gearing to model the precession of the axes of this ellipse around with respect to the fixed stars, revolving once in around 19 years. This is about 1600 years ahead of Kepler and astronomical clocks of that period, such as the Great Astronomical Clock in Prague, Czech Republic.

How else were the ancients Greeks to predict lunar and solar eclipses? For this is what the Mechanism was built to do, as well as being a sophisticated calendar. Just imagine if 2000 years ago you were able to predict a total solar eclipse, down to the very hour, using this Mechanism. The "maths" behind it all was in fact dead reckoning, as eclipses repeat on a slightly more than 18 year cycle - this being an integer number of "anomalistic months", this being the period from when the Moon's orbit, tilted by 5 degrees to the Earth's, crosses the Earth's orbit and is thus in the position to go in front of the Sun as seen from the Earth. The dead reckoning comes from records inscribed on the eclipse dial of eclipses over an 18-year cycle, records which most likely came from ancient Babylonian records from between 300 and 150BC. In fact, since the exact repeat period of eclipses contains 8 hours over an integer number of days, eclipses in the cycle are seen from points on the Earth which differ in longitude by 120 degrees. So to see an eclipse from the same place requires three eclipse cycles, or 54 years, this being recorded in a small subsidiary dial divided into three segments, which takes 54 years to revolve.

Michael Wright, who worked on this mechanism for 15 years gave a talk in which he said how similar the new view was to his own view of the mechanism, based on film X-ray images taken in 1990. He said how it only took 3 hours to modify his model of the mechanism, a beautiful model made of brass which he brough with him. The modification was small but altered the meaning of a whole train of gears, the purpose of which now makes so much more sense. Michael is a flamboyant character who contrasts greatly with the quite nature of Tony Freeth and listening to their discussion was quite entertaining!

I was interviewed for Radio 4 by Aubrey Manning - the man who did that wonderful series "Earth Story", and Prof. Mike Edmunds, the lead UK academic on this got onto the PM program on Radio 4. http://www.bbc.co.uk/pm - click - "Listen Again" and go to 53 minutes from the start.

The public session this evening was absolutely packed. I just couldn't imagine 450 people coming to listen to a lecture about Stonehenge in Britain, half of them having to stand for three hours. No way! But that's just what happened this evening. X-Tek's owner, Roger Hadland, who spoke at the evening session with a Greek translator, said he was embarassed - there were so many Greek people coming up to him and shaking his hand and thanking him. Our CT work was key to the recent findings showing loads more buried text under the corrosion of 2000 years under the sea. Tony Freeth, the main man behind the project almost got a standing ovation - people clapped for so long after his talk - even though it was given by a Greek colleague.

Did you know that this thing not only modelled the elliptical orbit of the Moon around the Earth (I thought Kepler discovered those in the 16th century - wrong!) it also modelled the precession of the nodes of the Moon's orbit, every 19 years, by using a clever offset quadruple circle mechanism, one gear being driven by another using a pin in slot method, so that the speed of the driven wheel varies almost exactly as the Moon's orbital speed varies. Only this way could they predict eclipses down to the nearest hour!!! Which is the main purpose of the Mechanism. Truly amazing!

It's nearly 3am - I'm so tired after such an interesting day. We only went to eat at 10.30pm - a table of around 20 of us.

Well our work mail server is up, but no mail from you som hopefully you can make use of this.

All the best,

Andrew.

Report on the second day of the conference in Athens:

Well we all thought we'd learned everything yesterday. What the purpose of the Mechanism was - everything fell into place. But no. Today we learned even more.

The first lecture, by Alexander Jones of the University of Toronto, Canada, questioned the usefulness of a wheel which gave us the eclipse months, dates and times for a complete Saros period - a period of just over 18 years in which the eclipses repeat almost indentically. Since this cycle is an integer number of days plus 8 hours, the times will be all wrong next time around. But no! There's this wheel with three divisions on it, and hidden in the CT data of it, there are two inscriptions - the ancient Greek letter-representations of the numbers 8 and 16. The third sector is blank. Jones's interpretation of this is the number of hours to add to the given time for the second and third Saros cycle. After three Saros cycles or 54 years, known as the exiligmos cycle, the eclipses repeat to within one hour. A true vidication of the use of the Mechanism.

After this, Clive Ruggles of Leicester University gave us an idea of how the Mechanism fits into the broader context of ancient calendars. He warned against the idea that progress in the past was a continuous progression of improvements until we reach the present day. He gave a great example of an Ethiopian tribe, who base their calendar purely on the Moon. It gradually gets out of step with the Sun, but they don't care. "Oh the Sun is a bit slow this year" they say! Who says all peoples used to worship the Sun as a God?

Four more lectures on other evidence around the time of the Mechanism lent weight to it being from that period (the late second century or early first century BC) and showed other documentary evidence that the ancient Greeks knew far more about astronomy than we used to give them credit for. Coffee break was taken up with an interview for Greek TV - on how we brought our X-ray system (www.xtekxray.com) from the UK to Greece and how I felt to be the first person in 2000 years to read the hidden text that our CT showed.

After a lunch provided by the Greek Ministry of Culture, the afternoon was taken up with discussions on the future of the Mechanism. How to preserve it, protect it from theft or earthquakes, and finally what further data academics and the public want from our project (www.antikythera-mechanism.gr).

Professor Mike Edmunds of Cardiff University, the lead academic of the project concluded by saying that all this wonderful technology, including whatever else the ancient Greeks had developed at that time, somehow got lost for over 1500 years. The "products of rational beings", as the Roman statesman, Cicero called the Mechanism, somehow got lost due to the influence of irrational thought. Prof Edmunds warned that the same could happen today if we are not careful and then maybe we'd be plunged into another dark ages of 1000 years or more.

After a great evening meal when 20 of us speakers sat together in the Rozalia restaurant, we all retired for a well-earned rest.

Tomorrow we're all going to the National Archaelogical Museum in Athens to see the Mechanism for ourselves. Of course I saw it last October during our inspection, but it'll be good to see it again - it's becoming an old friend!

Cheers,

Andrew.