Myths and Eclipses

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Two Carnivals

Two science-based blog carnivals have gone online recently. At Pharyngula the Creation Museum Carnival has just gone live. I appreciate the freedom of speech issue. If someone wants to spend millions of dollars fighting against science that it their right, but there’s no need to agree with or even respect dishonesty.

More cheerful is the Carnival of Space, hosted by Universe Today, which has a collection of links on Space Science and Astronomy from various weblogs.

The Antikythera Mechanism and the Birth of Science?

[Cross-posted to Revise & Dissent]

We had a talk recently at Leicester from Mike Edmunds, the professor at Cardiff who’s been leading the research into the Antikythera Mechanism. I plan to write more about that in the future, but one of the many highlights of the talk was that the mechanism has implications for how Greeks thought about Natural Philosophy, the precursor to Science.

The ancient Greek view of the world is strange. Sometimes you can be stunned by the skill of their observations, like when you see the Antikythera Mechanism. Other times their beliefs appear to make no sense at all. For instance the Athenians closed their silver mines in the winter – to allow the silver to grow back. Something that’s puzzled me is how people who were not stupid could think such a thing. Surely someone would have noticed the rock was as it was at the end of last season? One possible answer is that until the invention of devices like the Antikythera Mechanism there was no alternative.

600-1: A Tomb of Jesus follow-up

I’ve just had an email. Prof Andrey Feuerverger has put up reasoning behind his 600-1 figure online. It helps make more sense of an odd claim and appears to confirm that this is an example of the Prosecutor’s fallacy. For example here are some of the assumptions:

• We assume that ‘Marianemou e Mara’ is a singularly highly appropriate appellation for Mary Magdalene. Note that this important assumption is contentious and furthermore that statistically this assumption drives the outcome of the computations substantially.
• We assume that Yose/Yosa is a highly appropriate appellation for the brother of Jesus who is referred to as Joses in Mark 6:3 of the NT.
• We assume that the Latinized version Marya is a highly appropriate appellation for Mary of the NT.
• It is assumed that Yose/Yosa is not the same person as the father Yosef who is referred to on the ossuary of Yeshua.
• We assume that the presence of Matya does not invalidate the find but we assign no evidentiary value to it…

These assumptions are the very things we are testing for. It is claimed the statistics help prove that one of these ossuaries is of Mary Magdalene, but the statistics in fact are part of the claim that Mary Magdalene was buried with Jesus.

Something else that doesn’t make sense: The Tomb of Jesus

Another test podcast recorded as I picked up a cold. The claims around the Tomb of Jesus are… Well by now everyone knows.

I’d be more impressed if it were the Tomb of Brian

[Cross-posted to HNN: Revise & Dissent]

I’ve been working through the statistical analysis of the Tomb of Jesus data provided by the Discovery Channel (PDF download). They argue that the chances of their tomb not being the tomb of Jesus are one in six hundred. I looked through it and found two major errors. One is simple to see if you’re a historian, and the other should be blindingly obvious to a statistician.

The odds were calculated by Prof Andrey Feuerverger, Professor of statistics and mathematics at the University of Toronto. He was given names found on four ossuaries, boxes for holding skeletal remains, from a tomb in Jerusalem. The names were in English translation Jesus son of Joseph, Mary, Jose, a dimuntive of Joseph and Mariamne. It’s argued that Mariamne is Mary Magdelene and Jose is a diminutive of Joseph, which makes hime Jesus’s brother. What Prof. Feuerverger did was look at how often these names turn up in this historical record and then calculate the probability that these would turn up in a tomb somewhere.

He started by saying:

Jesus, son of Joseph	Jose	Mary	Mariamne	Total
1/190	1/20	1/4	1/160	1/2,432,000

Then he divided by four to allow for historical bias. Why four is never explained. This gives a probabilty of finding the names in one tomb as 1/608,000. Obviously there was more than one tomb in Jerusalem in the first century CE. Prof Feuerverger uses a figure of 1000. This reduces the odds of finding a tomb which could be said to belong to Jesus to 1 in 608. Generally social scientists get interested around odds of 1 in 20, so this looks impressive.

The Orientation of Roman Camps

I’m working on a problem which means I have to work out if a given set of astronomical alignments are significant. I have a possible solution, so now I’m testing it one someone else’s data. What I’m doing is treating the data as a Binomial Distribution. I have a few aims with this technique. First it has to give reliable results. Next I have to understand it. Thirdly and equally importantly I have to be able to describe it so that archaeologists and historians can follow the argument. If they can’t then it gets pointless writing. My analysis may not be correct, so I’m putting it up here and submitting that to Carnival of Mathematics and Tangled Bank to see if people think the maths is wrong. I’m also putting it up on Revise and Dissent where it will get submitted to the History Carnival and Four Stone Hearth to see if it’s intelligible and sounds reasonable to Historians and Archaeologists.

Roman Camps and their Orientations reconsidered.

There is currently a debate in the pages of the Oxford Journal of Archaeology on the orientations of Roman camps and forts. Richardson (2005:514-426) argues that the orientation of these camps is non-random and relied on some form of astronomical observation. He presents data which he argues supports his case. Recently Peterson (2007:103-108) has argued this relies on a flawed use of the Chi-squared test. I accept Peterson’s findings that Chi-squared is not a useful method. However examining the camps as a binomial distribution would be feasible and would make explicit the archaeological and astronomical assumptions made in the argument.

What is a Roman Camp?

The sites being examined are Roman camps and forts in England. One of the major advantages that the Roman army had over the native opposition when occupying new territory was their organisation. The Roman army was effectively a professional army taking on amateurs. Their camps reflect this organisation. Typically their early camps a ditch surrounded by a bank in a playing-card shape. They followed a set design. The rationale for this was if there were attacked by surprise equipment and people would be in the same place at each camp, minimising the effects of the surprise.

A Roman fort at Wallsend. Photo from Google Earth

The ancient sources give some detail on how to lay out a Roman camp. The main gate should face the enemy, or the line of advance (Vegetius 1.23, Hyginus 56). The rear gate should be on the higher ground to aid surveillance. Sites overlooked by hills were considered a bad idea, as were sites near woodlands which would allow the enemy to sneak up on the camp. The basic layout of the camp could be set up quickly by surveyors using gromae, surveying tools for laying out lines at right angles. Hyginus (chapter 12) states that you set up your groma at the junction at the centre of the camp and lay out your roads to the gates from there.

This would appear to be an efficient method of laying out a camp. Were observations to orientate the camp also part of the method? It doesn’t seem necessary, but Richardson (415,422-23) provides quotes from ancient sources which suggest this is plausible hypothesis in some circumstances.

Ithaca Found?

[Cross-posted to Revise & Dissent]

Drilling for Ithaca. © Robert Bittlestone.

Some tremendously exciting news was announced yesterday. Ithaca, the home of Odysseus from Homer’s Odyssey, may have been located. The reason why I’m finding it so exciting isn’t so much that from what they’ve found, but from the way that different strands of evidence are coming together to confirm the idea.

Locating Ithaca has long been a puzzle, complicated by the fact that Homer may have been making some of the description up for dramatic effect. For instance he refers to wealthy Corinth, which was nowhere special at the time of Trojan Wars and didn’t become a major power till much later. So there was the possibility that something similar was true of Ithaca.

Ithaca was described in the Odyssey:

I am Odysseus, Laertes’ son, world-famed
For stratagems: my name has reached the heavens.
Bright Ithaca is my home: it has a mountain,
Leaf-quivering Neriton, far visible.
Around are many islands, close to each other,
Doulichion and Same and wooded Zacynthos.
Ithaca itself lies low, furthest to sea
Towards dusk; the rest, apart, face dawn and sun.

Odyssey 9, 19-26 (trans. James Diggle)

The island known in modern times as Ithaki is currently thought to be Ithaca, but there are problems. Ithaki is hilly, among other islands and slopes to the east. Paliki would be a much better fit for the description, but there’s a problem there too. Paliki isn’t an island, it’s a peninsula on Kephalonia. Robert Bittlestone has looked at the isthmus connecting Paliki to the rest of the island and he’s come up with a solution. He thinks the isthmus is infill of a marine channel and that, in ancient times, Paliki was an island. However the isthmus is up to 180 metres above sea-level. Is this reasonable?

The Star of Bethlehem

[Cross-posted to Revise & Dissent]

Did Giotto get the birth of Christ right after all?

When people hear that I study ancient astronomy, a question I tend to get asked every so often is “What was the Star of Bethlehem?” There’s a few exciting explanations, so mine tends to disappoint. I’m pretty much of the same opinion as Martin when it comes to explaining Biblical miracles. There’s no independent evidence that many of these happened as described. There are however lots of strange events recorded in the ancient literature, and many honest misunderstandings. A lot of questioners assume the star must have existed, and therefore it’s simply a matter of explaining what it was. If this were a star of Apollo or Ueuecoyotl then fewer people would be convinced the star existed. Another problem is that just because you can spot a pattern it doesn’t mean it’s meaningful. I can see a duck-shaped cloud out of the window. I can’t believe it’s a divine sign that God is fed up of people eating turkey. Similarly, while there are a lot of astronomical events you could say were a star, they don’t really withstand much scrutiny. However, I am open to the idea that I need to change my mind, because I have read an explanation that might work.

The Antikythera Mechanism

A paper on the Mechanism appears in tomorrow’s Nature. In brief what it is these days is a rather unimpressive looking lump of heavily corroded metal. I have a photo of it somewhere, but it’s a very bad blurry photo which doesn’t do justice to its lumpy unimpressiveness. Fortunately Wikipedia has this much better photo.

The Antikythera Mechanism in the National Museum, Athens. Photo from Wikipedia.

The reason why it’s news is that there’s been a lot of painstaking work to try and see beyond the corrosion, and its proven spectacularly successful. The mechanism has been examined using X-ray tomography, which is where X-rays are used to build up a cross-section of a subject slice by slice without physically pulling the subject apart. The results are confirming that Greek technology could be staggeringly sophisticated.