Date: March 4, 2009

Title: Happy Birthday Apollo!

Podcaster: Cheryl Hurkett and Alun Salt

Organization: University of Leicester, Centre for Interdisciplinary Science http://www.le.ac.uk/i-science

Description: Today is the most likely date for Apollo’s Birthday. However it’s not just a matter of finding it marked in a calendar. For the ancient Greeks the calendar was used as much as a political tool as it was timekeeping. How then do you mark a date without making a political statement? A clue has been found in an ancient text dating from the 8th century BC.

Bio: Dr Cheryl Hurkett is an X-Ray astronomer at the University of Leicester specialising in the observation of Gamma Ray bursts using X-Rays. Her current research is currently sifting through data from the Swift satellite looking for evidence of Gamma Ray Bursts. She is a keen fan of cake. Alun Salt is an ancient historian and archaeologist. His research has been looking at astronomical orientations of Greek temples to see if there are any correlations between astronomy and religious practice. At the time of recording he had not been doctored.

Today’s Sponsor:  This episode of 365 Days of Astronomy is sponsored by Palomar Observatory, a world-class center of astronomical research that is owned and operated by the California Institute of Technology. Learn more at www.astro.caltech.edu/palomar/

Transcript: 

Happy Birthday Apollo

(Cheryl Hurkett) CH: It’s always embarrassing when you forget someone’s birthday. If you forget the birthday of a god though, the consequences can be serious. Recent historical and astronomical research has found that today is possibly the birthday of the god Apollo. The clue has been found in ancient texts which describe the earliest Greek astronomy.

I’m Cheryl Hurkett at the Centre for Interdisciplinary Science at Leicester and I’ve been able to grab Alun Salt, one of the researchers, to find out how you find a god’s birthday. Why get excited about a gods birthday? Apollo was an important god, so why not look it up in a calendar?

(Alun Salt) AS: Yes you can look it up in a calendar. We happen to know his birthday’s on the seventh day of the month of Bysios. The problem is that we don’t know exactly when. The Greeks used a lunar calendar. As far as they were concerned the month went from one new moon to the next and this doesn’t really fit in very well with the solar year. So sometimes you have to insert an extra month, sometimes you don’t. This leads to all sorts of problems.

CH: But how could that work? Surely there’d be different observation in different cities. The weather wouldn’t be the same and neither would the eyesight of an observer. Wouldn’t the calendars be out of step?

AS: Well that’s the second problem, because yes, you’re right there would be all sorts of things of out step and that might have even been the point of a Greek calendar. Calendars in ancient Greece weren’t just about time. They were also about religious event and they were about politics. Religion in ancient Greece was very much tied to the local city that the event was being held in. Taking part in a religious event is making a political statement and being able to time this by putting it in a calendar is also making a religious statement.

CH: So saying something will happen on a certain date is making a political statement?

AS: Well that as well, yes. Again, you all you have all this tying in of politics, religion and the locality of the place where you hold these events and who’s allowed to take part.

CH: How can you organize pan-hellenic events like the Olympics then?

AS: For the Olympics they eventually used heralds to announce when training should begin and when the games were. But for a lot of events this wasn’t practical. Instead they used the heliacal rising of stars.

CH: Heliacal rising is an event that happens because the earths rotation against the stars is slightly faster than against the sun. There’s an extra rotation the earth makes with respect to the stars each year because as the earth orbits the sun. If you look towards the eastern horizon at sunrise each day you should see new stars near the horizon just before sunrise. The first day you can see a star just before sunrise blocks it out is it’s heliacal rising.

Is there any evidence the Greeks knew about heliacal rising?

AS: It seems it’s probably one of the earliest forms of Greek astronomy.  We find it in works and days, a farming manual written by Hesiod in the 8th century BC and it seems to be used alongside weather signs and the migrations of animals to mark periods without having to use a calendar. It’s very useful not least because it’s pure observation it doesn’t need any geometry or any further theory of how the sky works.

CH: So where does Apollo come into this?

AS: What I found was that where we can date rituals to Apollo Delphinios they seem to follow the helical rising of stars in the constellation Delphinus. Delphinus is a useful constellation to be a marker because the stars are all roughly the same brightness and they’re all very closely packed together in the sky, so they all heliacally rise round the same period. In this period that heliacal rising is just after the winter solstice. If we look at all the places like Athens and Olous we find that rituals to Apollo Delphinios follow this event.

There’s only one place I know of where this idea doesn’t work.

CH: Wheres that?

AS: That would be Delphi, the place where you could consult the oracle on Apollo’s birthday.

CH: That would seem to torpedo the idea.

AS: Yes, it would wouldn’t it really? Fortunately I knew an archaeologist who’d gone out there to astronomically survey the temple. What she found is that the temple of Apollo at Delphi is in quite an odd location. It doesn’t look out towards a distant horizon, so you’re not looking out towards a rising sun or much of a rising anything. Instead it’s smack in front of some cliffs. It’s a really bad place for a view. One of the upshots of this is that if to see something rising at Delphi then it’s always going to happen a lot later than anywhere else.

CH: how long is this delay?

AS: Luckily for me it’s about a month and that matches how far Delph’is calendar is out of sync with the rest of Greece. Their ritual to Apollo Delphinios was held roughly around our February / March time in comparison to everywhere else where it was held January, possibly early February. Reconstructing the sky these days, because the stars have shifted position,  means that today is probably the best guess for a match for Apollo’s birthday.

CH: Useful if you’re a pagan but are there wider applications?

AS: Possibly. There’s a few historians finding similar signs for other events. If this method stands up and if we’re able to apply it elsewhere were using stands up then we should be able to explains more events and we should be able to pin down more dates for events. That means we can use astronomy more reliably to be able to pinpoint battles and put together a better chronology for ancient history. It’s no help with the biggest problem though.

CH: What would that be?

AS: What do you buy a god for his birthday?

CH: Have you thought of buying cake? Cake is always good.

AS: Oddly enough cake is probably one of the sacrifices made to Apollo. It had to be a cake of high quality but that, along with the traditional goat, do appear to turn up in the sources.

CH: Interesting! More seriously where can I find out more about this research? Well for March we’re going to stick it on <a href=” http://www2.le.ac.uk/departments/interdisciplinary-science/the-isciences-weblog/astronomy-and-the-oracle-of-delphi“>the Interdisciplinary Sciences website at Leicester</a>. You can find that at www.le.ac.uk/i-science.
End of podcast:

365 Days of Astronomy
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