There are more things in heaven and earth, cobber, than are dreamt of in your philosophy

This post was chosen as an Editor's Selection for ResearchBlogging.org Study­ing astro­nomy in cul­ture should be simple. There’s only so much that is vis­ible by the naked eye, and it fol­lows pre­dict­able pat­terns. Mod­ern astro­nomy means that we can recon­struct what was vis­ible any­where in the world in human his­tory, within cer­tain bound­ar­ies for errors. If we know what hap­pens when, then study­ing a cul­ture should just be a case of tak­ing a shop­ping list of astro­nom­ical phe­nom­ena and see­ing what a cul­ture does with them. And some bad his­tor­ies of astro­nomy read like the author is award­ing marks to cul­tures for astro­nom­ical achievements.

There’s vari­ous things that don’t work with that plan, but the biggest is that you sup­posedly are examin­ing cul­ture and are fit­ting a study to a very spe­cific view of astro­nomy, a mod­ern west­ern view. It’s awk­ward because we live in a cul­ture where a mod­ern Pla­tonic view of sci­ence is rarely chal­lenged. There’s a good reason for that. Our view of sci­ence makes sense within our cul­ture. But if we don’t acknow­ledge that sci­ence is a social con­struct then we don’t fully under­stand other cul­tures. Real­ity is the same for all of us, but not our way of mak­ing sense of it. An Over­view of Aus­tralian Abori­ginal Astro­nomy by Philip A. Clarke in Archae­oastro­nomy is a good paper that helps show the dif­fer­ence between under­stand­ing the use of astro­nomy in a cul­ture and com­par­ing an indi­gen­ous astro­nomy with ours to see how much they got right.

The paper starts at the very best place to start, as after a brief intro­duc­tion it con­siders the sources of the data. It’s a key point because if the source data is full of lead­ing ques­tions and pre­con­ceived notions then you’ll only get the answers you were look­ing for.

Clarke then looks at how Abori­ginal peoples saw their world. If you’re going to exam­ine the sky, it helps to know how the people describ­ing it saw it in rela­tion to the rest of the world. A com­mon fea­ture of abori­ginal cos­mo­logy is that the sky was seen as con­nec­ted to the land. Clarke refers to the sky as the “Land of the Dead” or the “Land to the West”, because spir­its are thought to travel to the west to enter the sky. The meth­ods of get­ting there var­ied. Tas­mani­ans saw their foot tracks in the forest as lead­ing to the Milky Way. This reminds me a bit of the Green­landic idea that the shaman could walk to the moon. In the far north the moon can roll across the hori­zon, so that it has a vis­ible con­nec­tion to the Earth. From that view the idea that the Milky Way is a foot track con­nec­ted to the Earth where it meets the hori­zon makes sense. Oth­ers have the idea that birds could trans­port people to the Sky­world, which again matches obser­va­tions of birds being between land and sky. Still more say that you can reach the Sky­world by climb­ing tall trees and get­ting help from a passing tornado.

The abori­ginal Sky­world seems to be a very richly described place. The abori­gin­als have no truck with celes­tial spheres. Their Sky­world has topo­graphy, trees and inhab­it­ants. The Sky­world is where the ancest­ors live, and so it’s a handy place to visit if you’re in need of a bit of ancient wis­dom. They should be easy enough to find as some of the ancest­ors are thought to be vis­ible as stars.

The iden­ti­fic­a­tion of ancest­ors in the sky brings a whole series of fur­ther factors. Kin­ship is import­ant in abori­ginal soci­ety and the same is true for the ancest­ors. Ant­ares is Butt Kuee Tuukuung in south­w­est Vic­toria, and the fainter close stars are his wives. Bright­ness and loc­a­tion explains a lot of the other rela­tion­ships that Clarke lists. Time is also an issue. In north­ern Queens­land the Even­ing Star is Dog and the Morn­ing Star is Bitch. All these fea­tures are cat­egor­ised in clans and sec­tions just like the rest of the abori­ginal world includ­ing anim­als and plants on the land.

Opin­ion is divided on how the Sun and Moon return from the west to the east. For some people this is through a path in the under­world. The people of Arnhem land have a tale the Sun becomes a great fish and swims under the land through the ocean. That appeals to me at a nar­rat­ive level. Other regions have other tales and some include the pas­sage of stars beneath the earth as well as the Sun and Moon.

One of the inter­est­ing fea­tures that comes out of this paper is that the Abori­ginal people seem to have a concept of stars, but not so much of stick-figure con­stel­la­tions. Clarke men­tions a sur­vey by Haynes that finds evid­ence of some faint stars being Unwala the Crab Ancestor [PDF], but not both­er­ing with Pro­cyon and Reg­u­lus — two much brighter stars close by. My reac­tion was that maybe this shouldn’t be too much of a sur­prise. If a bright star is an ancestor then it’s an indi­vidual not part of a lar­ger fig­ure. There are already kin­ship con­nec­tions between stars so the idea of Greco-Roman style con­stel­la­tions is prob­ably a bit too con­fus­ing. Another factor is that because the Milky Way is so vis­ible, there are already plenty of dark-cloud con­stel­la­tions that actu­ally look like things. For example one patch of neb­ula in the Milky Way blots out the stars mak­ing the sil­hou­ette of an emu in the sky. That makes draw­ing stick fig­ures between stars an uncon­vin­cing altern­at­ive for con­stel­la­tions. But there are other bet­ter reas­ons too.

Clarke makes the point that col­our is very import­ant in abori­ginal cos­mo­lo­gies. One example he gives are the Arrente people of Cent­ral Aus­tralia who give more import­ance to red­dish or white stars than yel­low or blue stars. It won’t sur­prise you the same people value red ochres and white clays as sym­bols of power. Col­our becomes more com­plic­ated when you exam­ine the Sun or Moon, which are red at the hori­zon but change col­our as they climb and fall. A red Sun seems to a par­tic­u­lar prob­lem as it’s a fem­in­ine sym­bol and red is a power­ful col­our. One tra­di­tion describes it as a kangaroo skin dress that is given to her by men who spend the night with her. The mottled face of the Moon seems to be explained by scars of con­flict, but the exact nature of the fight var­ies from region to region.

Clarke cov­ers time­keep­ing, espe­cially sea­son­al­ity in depth. The only thing I’ve found miss­ing here is when the day starts. Some cul­tures see it start­ing at sun­rise, oth­ers at sun­set but I’ve no idea if there’s a shared day concept in Abori­ginal cul­ture. The Plei­ades seem to be par­tic­u­larly import­ant in the turn­ing of the sea­sons [PDF]. Clarke notes that Tindale has fifty dif­fer­ent ver­sions of Plei­ades myth­o­logy con­nect­ing them to chan­ging of the sea­sons. That might indic­ate a lot of dis­agree­ment, but the fact that so many abori­ginal cul­tures over such a large area are using the same gen­eral idea and dis­agree­ing on the details points to inter­con­nec­tion between peoples.

The sad­dest sec­tion is The Col­lapse and Rebirth of the Cos­mos. Abori­gin­als did not pass­ively sit wait­ing for white set­tle­ment and news of the Europeans pre­ceded their arrival in many places. Clarke can show this is reflec­ted in their cos­mo­logy. The Brit­ish arrived in the east and thanks to small­pox brought death with them. Vis­ions of the Aurora Aus­tralis and met­eors were inter­preted as omens of dire times. Given the res­ults it’s easy to see how the arrival of the Brit­ish could be seen as a cos­mic apo­ca­lypse.

The com­mon theme in this paper, apart from sheer vari­ety and oth­er­ness of abori­ginal astro­nomy is that this is also a con­tinu­ing tra­di­tion. I’m acutely aware I may have mixed up tenses in the descrip­tion because some of these ways of life have gone, while oth­ers are still alive. This life isn’t simply a rut that people return to, but a tra­di­tion that can adapt can appro­pri­ate new ideas, like Abori­ginal beliefs about UFOs, or sci­entific dis­cov­er­ies. Clarke men­tions the met­eor­ite strike that cre­ated the Wolfe Creek Crater has been woven into tales of the Dream­time.

Astronomically inspired indigenous art at the Ilgarijiri exhibition on display in Geraldton. Photo (cc) AstroMeg.
Astro­nom­ic­ally inspired indi­gen­ous art at the Ilgar­ijiri exhib­i­tion on dis­play in Ger­aldton. Photo (cc) AstroMeg.

Good writ­ing can trans­port you to strange new places. Some­times its an evoc­at­ive geo­graph­ical descrip­tion, but it can also show you the uni­verse in a new light. Astro­nomy can show the majesty of the cos­mos and the sheer scale of cre­ation. At the oppos­ite end of the scale you can go on safari with micro­scopic bac­teria far too small to be seen by the human eye. In the case of work like Clarke’s, it can be a guide to show how spe­cial the appar­ently mundane is. The night sky we see is more or less the same as seen by the abori­ginal peoples of Aus­tralia, allow­ing for some effects of lat­it­ude of the observer.

What I like about this paper is that at each step Clarke is link­ing back to the cul­ture that the astro­nomy is in. The fact that abori­ginal astro­nomers are inter­ested in the col­ours of stars is, by itself, a foible. Because Clarke makes that point that col­our is con­nec­ted to all sorts of ter­restrial sym­bol­ism and mean­ing then the con­nec­tions between sky and soci­ety become much more mean­ing­ful. Like­wise the lack of con­stel­la­tions might be taken as a sign that Abori­ginal peoples aren’t that inter­ested in many stars. Know­ing about the kin­ship sys­tem shows how mis­taken that is, and that state­ments about the Sky­world are also strong polit­ical state­ments about life in the world below.

The many pages of ref­er­ences at the end of the art­icle are the icing on the cake, because this paper is very much an over­view. Any single sec­tion of the paper is a gate­way to many many more art­icles research­ing abori­ginal astro­nomy and cul­ture. You never want to take one author’s work as the last word on a sub­ject, but if you’re inter­ested in Aus­tralian indi­gen­ous astro­nomy you could do a lot worse than take Clarke’s art­icle as the start­ing point.

ResearchBlogging.orgClarke, P.A. (2007). An Over­view of Aus­tralian Abori­ginal Eth­noastro­nomy Archae­oastro­nomy: The Journal of Astro­nomy in Cul­ture, XXI, 39–58 (Mendeley link)

8000 years of genetic engineering in your fruitbowl

More blog­ging about research, without a Research Blog­ging logo, because this is way out­side my area of expert­ise — but it looks inter­est­ing. I spot­ted it going through the accep­ted papers list at Annals of Bot­any and ser­i­ously con­sidered put­ting this for­ward for a press release. I decided not to — I don’t fully under­stand it — and blog it instead. So I’ve been wait­ing for this to come out and slightly miffed that I missed it due to a cold. It’s not in the prin­ted journal yet, but you can see it now, and look at what I get wrong because it’s an open access paper.

The reason I’m going to make a fool of myself and blog it any­way is that this is research that is import­ant to the ori­gins of agri­cul­ture, one of the BIG archae­olo­gical prob­lems. And it’s about bana­nas, and everyone’s famil­iar with bananas.

Bana­nas are actu­ally strange. Aside from the fact that banana plants ‘walk’ (not really, see this excel­lent blog post), they’re also all clones. I also have to admit that if I saw a banana in the trop­ics I prob­ably wouldn’t recog­nise it. The big yel­low curvy fruit I think of as a banana is just one of many vari­et­ies. As a starchy plantain Musa (some of which are bana­nas) are a staple diet in Asia. They have been for thou­sands of years and they’re sterile so there’s a bit of a mys­tery. How can they still be here?

Kadali. Photo (cc) Dinesh Valke
Kadali, a type of Musa plantain, like banana. Photo (cc) Dinesh Valke.

The bana­nas we have today are the products of thou­sands of years of care­ful selec­tion for spe­cific traits by farm­ers. The ancient people doing this had no concept of ‘genes’, but if we were to do the same sort of thing today we’d be genet­ic­ally engin­eer­ing the plant. The reason ancient people did this is because edib­il­ity and seeds are prob­ably not com­pat­ible in bana­nas. Get a muta­tion without seeds and you have an edible berry. You don’t have seeds though so you have to start propagat­ing it more inventively.

Lack of banana sex means that the genetic diversity of these plants is very lim­ited. If you have a pest that can kill one plant, you’ve got a pest that can wipe your entire crop and you neigh­bours’ crops. So it would be amaz­ingly help­ful to be able to trace back the genetic his­tory of bana­nas to see where they came from and how they were domest­ic­ated into their cur­rent form. That’s what the authors of ‘Did back­cross­ing con­trib­ute to the ori­gin of hybrid edible bana­nas?’ pro­pose to do.

What they’ve found is that it looks like edible bana­nas are hybrids. That might not be such a sur­prise. What they’ve also found though is evid­ence of care­ful thought in hybrid­isa­tion to favour some traits over oth­ers, using a tech­nique called back­cross­ing. I had to have this explained to me.

You have two banana plants A and B. If you cross them you can get a hybrid banana AB.

Basic diagram of banana genetics

Banana Genet­ics

Back­cross­ing is when you take this hybrid and cross it back with an earlier gen­er­a­tion. So if you take your AB banana and back­cross it with an A banana you get banana with much more A genes in it than B genes. You can take this new hybrid and back­cross it again with A or B to pro­duce the next gen­er­a­tion and so on. The authors have a math­em­at­ical model for this and I won’t pre­tend I under­stand it. It’s a shame, because that’s most of the paper.

With my archae­olo­gical hat on, it’s a use­ful paper. If you’re inter­ested in how the trans­ition to agri­cul­ture occurred in south Asia then clearly under­stand­ing banana domest­ic­a­tion is import­ant. The ancient bana­nas them­selves have long rot­ted away, to being able to pull apart the genes of a banana to see how it was domest­ic­ated is a massive help. If this paper is right, and the authors pro­pose a few exper­i­ments to test the idea, then the banana is the res­ult of some very clever and select­ive breeding.

The reason I’m par­tic­u­larly excited is that Annals of Bot­any also had a paper on domest­ic­a­tion of Pitaya di Mayo recently by eth­no­bot­an­ists. This was a study of domest­ic­a­tion as it hap­pens. The kind of local selec­tions for spe­cific traits that Mex­ican farm­ers are using for pitaya look like they’d pro­duce the kind of com­plex genetic his­tory being found in bananas.

I live in a tem­per­ate zone, so the limit of my banana exper­i­ence till now has been that it’s a deli­cious, yel­low and some­times humour­ous fruit. Papers like this show that the banana going soft in your fruit bowl is an eight thou­sand year old con­nec­tion to some very clever farmers.

Past lives caught in the dust of trees

ResearchBlogging.org I’m cur­rently work­ing at the Annals of Bot­any to help out with their social media side. There’s a bit more to it than subtly drop­ping links to their site, like this one. At the moment I’m strug­gling with the Face­book integ­ra­tion, but there’s a fun side too. I wouldn’t have browsed AoB if I’d not been hired, and that means I would have missed out on papers like Phyto­liths in woody plants from the Miombo wood­lands of Mozam­bi­que by Julio Mer­cader and his team at Cal­gary. I’ll admit the art­icle title doesn’t say much to the lay­man, but it’s actu­ally some­thing deeply cool that I didn’t find out about till my MPhil.

If mega­liths are big stones and micro­liths are small stones like arrow­heads, then phyto­liths are clearly phyto-stones. Phyto– in this case mean­ing plant.

Phyto­liths are micro­scopic stones formed in some plants. When a plant’s roots draw up water they also draw up the min­er­als dis­solved within it. In the case of the silica this gets pulled out of the water and depos­ited either in the cells or between the cells. The exact shape of the phyto­liths var­ies on the part of the plant the silica is depos­ited in, the avail­ab­il­ity of silica and, most excit­ingly for archae­olo­gists, the spe­cies of the plant.

Phyto­liths are use­ful because nor­mally bio­lo­gical mater­ial doesn’t hang around long in the soil. Once some­thing is dead it’s lunch for some­thing else. Phyto­liths are bio­lo­gical mater­ial but not organic, so they don’t break down in the same way. Mer­cader et al. are clear that’s is not an unam­bigu­ous relal­tion­ship. Time still has an effect, but it’s easier to find phyto­liths than it is to find organic remains for plants. Still as use­ful as they are, phyto­liths alone are not enough. A hand­ful of phyto­liths under a micro­scope would just look like a nobbly (or smoothish) thing. If you haven’t seen what a baobab phyto­lith looks like, you’re not likely to guess from simply look­ing at the phyto­lith and this is where Mer­cader et al step in.

Elephants in Miombo woodland. Photo by Jussi Mononen.

Ele­phants in Miombo wood­land. Photo by Jussi Mononen.

If you’re inter­ested in study­ing the palaeoe­co­logy of Africa in the past you’ve been rel­at­ively lim­ited to north of the equator. Mer­cader spot­ted that the biggest phyto­chor­ion (plant eco­sys­tem) south of the Sahara is the Miombo wood­lands. It’s huge. It runs from Angola and Nam­i­bia in the west to Mozam­bi­que in the east and from the Tan­zanian shores of Lake Vic­toria in the north to Bot­swana and South Africa in the south. The dom­in­ant tree is Miombo, hence the name, which refers to a num­ber of trees of the same genus, but with dif­fer­ent spe­cies. Obvi­ously it’s a cru­cial zone for under­stand­ing the eco­logy of sub-Saharan Africa, but no-one has described the phyto­liths of the region.

Miom­bos Botan­ical Tran­sect after Mer­cader et al.

The area stud­ied was a tran­sect through the forest between the Lake Niassa shore at Metan­gula and the high­lands at Njawala, a dis­tance of 50km and a rise from 465m above sea-level to 1841 above sea-level. They also used indi­gen­ous col­lect­ors to sample the flora in a 5km radius around Metan­gula and Njawala. They estim­ate they got over 90% of the spe­cies used by the nat­ive peoples. Given that a lot of usage is likely to be dom­in­ated by rel­at­ively few spe­cies, that’s a lot of plant mater­ial. There’s then a LOT of list­ing and descrip­tion of phytoliths.

The com­mon fea­ture that amazes me is how small many of these phyto­liths are. Some are just 20–40 μm long. A micro­metre (μm) is one thou­sandth of a mil­li­metre. Des­pite this Mer­cader et al, point to the phyto­liths at the other end of the scale, some are around 200μm in length and over half are over 50μm. This means if you use stand­ard tech­niques to sieve for phyto­liths using a 50.238 to 63.246μm cut-off, you’ll miss all these lar­ger phyto­liths. That’s going to mat­ter if what you want to find evid­ence of a ‘Zam­bezian’ forest at an archae­olo­gical site.

It’s the sort of sci­ence that is easy to over­look. The authors don’t con­clude that whole text­books need to be re-written or that our under­stand­ing of Africa’s past has to be rebuilt from scratch. It’s also the kind of sci­ence that’s easy to whine about. Here they are, pick­ing flowers to exam­ine tiny stones in the stems rather than just appre­ci­at­ing the beauty.

But it’s also the kind of sci­ence that increases the amount of beauty and mys­tery in the world.

Until I took my MPhil, I was com­pletely ignor­ant of phyto­liths. I could view the same plants an archaeo­bot­an­ist, but saw a lot less. Before I read this paper I didn’t know that that the Miobos wood­lands were unex­amined. Know­ing that these things are out there opens up new pos­sib­il­it­ies for what can be done. At Çatal­höyük they’re examin­ing phyto­liths left behind in what are almost shad­ows of woven bas­kets to flesh out details of human life in the past. In the case of this paper, it provides a bench­mark for meas­ur­ing future study­ing against. It’s detailed, metic­u­lous and some­times opaque to the non-specialist, but it’s also a descrip­tion with last­ing value. Cur­rently pub­lic­a­tions are often judged on cita­tions garnered over a few years. That misses the value of this paper as it will be import­ant for dec­ades. Indeed, if this eco­sys­tem sud­denly becomes a tar­get for eco­nomic devel­op­ment it could even be import­ant for cen­tur­ies as a snap­shot of the cur­rent state of the Miom­bos woodlands.

If you want to see the phyto­liths they found, you can down­load the paper for free.

ResearchBlogging.orgMer­cader, J., Ben­nett, T., Essel­mont, C., Simpson, S., & Walde, D. (2009). Phyto­liths in woody plants from the Miombo wood­lands of Mozam­bi­que Annals of Bot­any, 104 (1), 91–113 DOI: 10.1093/aob/mcp097

Photo credit: Ele­phants in Miombo wood­land. Photo by Jussi Mononen.

Do we need an Industrial Archaeology?

Cromford Canal

Crom­ford Canal. Click for lar­ger image.

It’s easy to take a World Her­it­age Site for gran­ted when it’s on your door­step. I had thought of shoot­ing a short port­fo­lio of Crom­ford for a com­pet­i­tion. They required ten pho­tos. After look­ing into the pro­ject I’ve decided that the com­pet­i­tion isn’t going to hap­pen for me, but a short photo essay on Crom­ford, or pos­sibly the Derwent Val­ley Mills, remains an inter­est­ing idea.

Indus­trial Archae­ology can get short shrift from other archae­olo­gists. Often there’s writ­ten records, plans and for some places oral accounts of work at a site. Is Archae­ology neces­sary? Mark Hen­shaw, the Archae­ology Dude, makes a good argu­ment that Archae­ology can draw mul­tiple lines of evid­ence to inform his­tor­ies of the past. I wouldn’t dis­count that, and I think his point, Archae­ology isn’t just about dig­ging, is very import­ant from an Amer­ican per­spect­ive because there Archae­ology is seen as a branch of Anthro­po­logy. In the UK you’re more likely to see Archae­ology paired with His­tory or Clas­sics. So do we really need Indus­trial Archae­olo­gists when there so many Early Mod­ern Historians.

I think another factor Archae­ology brings is spa­tial think­ing. Look­ing at the early days of the pro­fes­sion­al­isa­tion of Archae­ology in Bri­tain, one of the fea­tures is an attempt to dis­tin­guish Archae­ology from His­tory by tak­ing on ideas of Geo­graphy. People like OGS Craw­ford were keen to emphas­ise that Archae­ology stud­ied human activ­it­ies in space as well as time. Again, in the UK, when Pro­ces­su­al­ism was tak­ing off in the USA, the Brit­ish aca­dem­ics took inspir­a­tion from it, but also from the ‘New’ Geo­graphy.

The Manager's House, Cromford.

The Manager’s House, Cromford.

Apply­ing this prac­tic­ally, it’s easy to say what the pos­i­tion­ing of the Fact­ory Manager’s house, oppos­ite the main gate of Arkwright’s Mill at Crom­ford, means by its loc­a­tion. There are other more subtle ques­tions though. What did draw­ing a second water chan­nel through the Derwent Val­ley mean for land use and access­ib­il­ity? Why was Willers­ley Castle, a grand house that Ark­wright built for him­self, placed where it was? How did it relate to the church he built? If you want to know why a mill owner would want to build a church for his work­ers then, as Mark Hen­shaw says, you have to look at his­tor­ical records too.

You can write a his­tory purely from his­tor­ical records and archives, but if you want to exam­ine the human exper­i­ence, espe­cially of humans that weren’t writ­ing much, then an Indus­trial Archae­ology can yield a richer, more four-dimensional exper­i­ence, than Anthro­po­logy or His­tory alone.

What does the new henge mean for Stonehenge?

Confusion at Stonehenge

Con­fu­sion at Stonehenge

I don’t know.

I think the cov­er­age at places like the BBC are good, David Gregory found it excit­ing and I thought his story was a good read. How­ever there are too many details miss­ing from the reports to come to any con­clu­sions. That’s not a com­plaint about the cov­er­age, the mass-media isn’t an archae­olo­gical journal. It’s not even a gripe about pub­lic­a­tion by press-release because Mike Parker Pear­son showed last year that news leaks out, so why not give the brief details out properly?

On the other hand the Birm­ing­ham team are look­ing at the land­scape and, from read­ing the reports, I’ve no idea where this new site is in rela­tion to Stone­henge. It’s almost cer­tainly in sight of Stone­henge, but then the land­scape round there is littered with bar­rows, Bronze Age burial mounds. The loc­a­tion will affect how we see the land­scape. This henge isn’t to be con­fused with Blue­stone­henge, the site found by the river Avon near Stone­henge last year. It’s also not Wood­henge, des­pite being made of wood, because that’s a dif­fer­ent site near Dur­ring­ton Walls, which is another site that has been in the news in recent years.

There’s not a lot I can say about the astro­nomy of this henge either. It could be aligned to the sum­mer sun­rise, but I can’t tell because the dia­gram doesn’t say which way north is. Also look­ing at the dia­grams, the stone circle seems to have entrances facing one axis and the tim­ber circle an entirely dif­fer­ent align­ment. In fact, the entrance to the wooden circle seems to be facing stones. To me, that sug­gests at least two phases to the monu­ment. I ima­gine that there’ll be some sort of test excav­a­tion along sim­ilar lines. If you want to take your time plan­ning an excav­a­tion it’s a very sens­ible idea not to flag up the loc­a­tion in the news.

Ground Penetrating Radar by Ben Urmston

Ground Pen­et­rat­ing Radar by Ben Urmston

The con­fu­sion that this find­ing is going to cause will be huge fun for Stone­henge watch­ers. The equip­ment they’re using is Ground-penetrating RADAR. This used to be rub­bish, some­thing you’d only use in an urban loc­a­tion where you got a good sig­nal, but as with everything involving a micro­pro­cessor it’s advanced massively. It means that there’s huge swathes of land where some com­pletely unex­pec­ted things will be found. In some­where as busy as the Stone­henge land­scape there has to be much more than this wait­ing to be dis­covered. It’ll raise some awk­ward ques­tions for archae­oastro­nomers, because des­pite there being align­ments will these newly dis­covered struc­tures have blocked the view?

The excit­ing thing about this work is that it shows not only to we not have all the answers, we don’t even have all the questions.

Photo credit: Ground Pen­et­rat­ing Radar photo by Ben Urmston.

Survey: How do you know you’re doing it right?

Archae­olo­gical sur­veys tend to be samples of a site. How do you know you’re doing it right when you can’t see the arte­facts you’ve missed? Couldn’t you be miss­ing large chunks of inform­a­tion because it’s not what you’re expect­ing to see? David Pet­ti­grew guest blogs at The Archae­ology of the Medi­ter­ranean World,

Astronomy at Ston̈ehen̈ge for the 2010 Summer Solstice

I’ve been busy, recently and I’m likely to stay that way for a while, hence the lack of posts. Still, I’m hop­ing to be able to take a trip to Stone­henge this year to see the sol­stice. That’s why my pre­dic­tion is that it will be cold and wet and thick cloud will pre­vent any­thing inter­est­ing mak­ing an appear­ance. How­ever, if there are clear skies, there could be plenty to see over Stone­henge this sol­stice.

Nat­ural Astronomy

There’ll be plenty to see in the even­ing sky after sun­set at 9.26pm. To the west Venus will be extremely bright at mag­nitude –4.0 (the lower the num­ber the brighter some­thing is). When you see it you won’t be able to mis­take it for any­thing else. That will be set­ting at a quarter to mid­night, so there’ll be plenty of time to see it.

Stonehenge astronomical chart for sunset solstice 2010

Pos­i­tion of the plan­ets at sun­set. Click for full size.

Mov­ing to the left, are Mars, Sat­urn and the Moon. Mars will be mag­nitude 1.3 so it won’t be the bright­est thing in the sky, Arcturus and Vega will be brighter but it’ll still be easy to find. If you’re strug­gling find the Plough. The two pointer stars that point up to the Pole Star will be more or less also point­ing down to Mars this even­ing. Mars sets at a quarter to one, but if you want to see it real­ist­ic­ally you’ll have to be look­ing before mid­night. If you’re lucky it’ll have a slight ruddy glow. Sat­urn will be the only bright object between Mars and the Moon. In fact it’ll be slightly brighter than Mars in per­fect atmo­spheric con­di­tions, but I doubt my eyes will be good enough to meas­ure that.

The Moon will be in Virgo, near the star Spica, which was thought to be a sheaf of corn in the hand of Ceres, if you’re Roman, or Demeter, if you’re Greek. Fans of myth­o­logy will be keenly aware that Demeter/Ceres had a daugh­ter with Zeus which makes her not tech­nic­ally a vir­gin, but the Greeks called her Parthenos and that usu­ally gets trans­lated as vir­gin. To find Spica usu­ally you’d fol­low the arc of the handle of the Plough to Arcturus, and then Spica is the next bright star down. This night it’ll be the closest bright star to the Moon. It could be hard to spot because the Moon will be bright. It’ll be 69% lit, nine days old and wax­ing gib­bous. It’ll be more or less low in the sky to the south at sun­set and set around 1am, which is astro­nom­ical mid­night. It’s not the same as civil mid­night because these days Stone­henge is on Day­light Sav­ing Time, like the rest of the UK.

Stonehenge astronomical chart for midnight solstice 2010

Stars at 1am over Stone­henge. Click for full size.

Around 1.20am Jupiter rises. It’s likely that you’ll need to wait till 2am to get a good view. It’ll be shin­ing in sil­ver at mag­nitude –2.4 and, because Venus will have set, it’ll be the bright­est planet on the sky. Jupiter will have a part­ner, but it’s highly unlikely you’ll see it at Stone­henge. Uranus will be close to Jupiter. If you hold out your hand at arm’s length then Uranus will be five or six little fin­ger­nail widths to the right of Jupiter. Nor­mally there’s no chance at all of see­ing Uranus, but at the moment it’s at mag­nitude 5.8 which puts it right on the limit of human vis­ion. If you have very good eye­sight and the atmo­spheric con­di­tions are per­fect you’ll see what looks like a very faint star next to Jupiter, and that’s Uranus. But even if we have that, I still doubt you’ll see it.

The reason is that it takes time for your eyes to adapt to the dark. Ian Mus­grave says it takes a few minutes to see down to mag­nitude 5 or 6. Your eyes need to build up chem­ic­als to make them more sens­it­ive. Every time you see a bright light, like car head­lights from the nearby roads, torches from other vis­it­ors who — quite reas­on­ably — don’t want to break their necks walk­ing around and any light­ing from Eng­lish Her­it­age this adapt­a­tion will be lost. On top of this there’s light pol­lu­tion. We don’t just use energy light­ing streets. A lot of energy is used to light up the sky, for no obvi­ous reason. This reflects from any water droplets in the atmo­sphere and gives a sodium glow to the sky. Even cit­ies over the hori­zon will be vis­ible by their light pol­lu­tion and this will pre­vent you from see­ing some of the stars. You’ll stand a bet­ter chance of see­ing Uranus if you use binoculars.

There is another difficult-to-spot object in the sky. To the north near Capella is Comet McNaught. Search­ing on the web for this is no help. There’s a lot of Comet McNaughts because Robert McNaught has found over fifty of them. This one is Comet McNaught 2009 R1. The cur­rent fig­ures I have are that it will be between mag­nitudes 5 and 6. If that’s the case then you might not see much without dark-adapted eyes and it’s a bin­ocu­lar object. This fig­ure is uncer­tain though because the comet is get­ting closer to the Sun. Around June 30-ish it’s pre­dicted to be as bright as mag­nitude 2. Capella is not too hard to find. It’s the only bright star above the north­ern hori­zon, and it will be due north around half-past mid­night. The comet will be a couple of degrees above it. Look for a fuzzy star.

The Sun is due to return a few seconds before 4.52am. Again, day­light sav­ing explains why the Sun sets less than three hours before mid­night, but doesn’t rise till almost five hours after.

IFOs

Or, if you don’t tell your friends what they are, UFOs.

The big events will be the passes of the Inter­na­tional Space Sta­tion. There’ll be two and half over Stone­henge. The first will be at 1.08am till 1.10am. You’ll be able to see the ISS drop­ping from 38º up in the sky to the south­east down to the hori­zon. It’ll be bright (mag­nitude –2.7) but it will also be fast. This is the half appear­ance and you may not see it. You best chance is to be look­ing at Aquila, the bright­est star in the south­east at this time, and it should appear near there.

The next appear­ance is the best. At 2.40am it will rise in the west and pass over­head before set­ting in the east at 2.46am. It will look like Venus did, but it will vis­ibly be mov­ing across the sky. It could look like an aero­plane and if any­one else says that you might want to agree before point­ing out that there’s no vis­ible flash­ing lights like there would be on an aero­plane. It will also be trav­el­ling too fast. Get your friends to rule out other obvi­ous causes like Chinese lan­terns, reflec­tions of head­lights, plan­ets and so on so that you sound like you’ve been reluct­antly con­vinced that whatever you saw was not of this world.

Then at 4.15am you can make every­one jump out of their skin by yelling “They’re BACK!” when the ISS makes another pass from the west again. This time it will set 4.23am in the eastsoutheast.

For extra UFO points you can also try point­ing out an Iridium flare. This is a sud­den bright reflec­tion from one of the Iridium com­mu­nic­a­tions satel­lites. There are two dur­ing the course of the night. At 10.52:44pm on June 20 there’s a mag­nitude –1 flare west­north­w­est above a hand­span above the hori­zon. At 3.22:06am there’s a brighter mag­nitude –4 flare in the east­south­east. These will be fast; they’ll last for just a few seconds.

Flare Sim­u­la­tion. Source: Wiki­me­dia Commons

Heav­ens Above, where I got these details from for the ISS and Iridium also has some transit times for fainter satel­lites, but the night sky is littered with satel­lites. If you see any­thing that looks star-like mov­ing across the sky over six-eight minutes then it’s quite pos­sibly a satel­lite. Some of these could be mis­taken for aero­planes. Regis­ter­ing on the site will enable you to print off your own star charts for ISS and satel­lite passes. If you’re on twit­ter @twisst can tell you when the ISS is passing over your loc­a­tion and send you alerts.

If you’re inter­ested in vis­it­ing Stone­henge for the sol­stice this year and want more prac­tical advice, like remem­ber­ing to pack toi­let roll, you’ll find Her­it­age Key help­ful. And if there are clouds, it might not all be bad news.

Blogging Archaeology at the SAA

Colleen Mor­gan has put for­ward a pro­posal for a Blog­ging Archae­ology ses­sion at the SAA con­fer­ence. My con­cern was that an explict blog­ging ses­sion would be case of preach­ing to the choir. Tech­no­phobes would have the con­veni­ence of skip­ping all the awk­ward talks in one pack­age. How­ever I think she’s proven me wrong. I think she’s got some use­ful ideas that could bene­fit from a con­fer­ence ses­sion, in par­tic­u­lar thoughts on pri­vacy. I think this is a poten­tial head­ache, espe­cially if courses are going to encour­age stu­dents to blog. It could be use­ful to help dis­tin­guish between anonym­ity and pseud­onym­ity, and a con­fer­ence might be the place to tackle this kind of ques­tion head on.

Sadly I don’t anti­cip­ate attend­ing the SAA con­fer­ence, but if there’s one ses­sion that will break out bey­ond the con­fer­ence, then you’d expect it to be the one about blog­ging. You should keep an eye on Colleen’s blog Middle Sav­agery for more devel­op­ments, but really Colleen is full enough of inter­est­ing ideas that you should be read­ing her blog anyway.

Planets and Anomalies in the Antikythera Mechanism

This post was chosen as an Editor's Selection for ResearchBlogging.orgMath­em­aticians have a concept, Omega, that is defined as some­thing so huge that any attempt to define it actu­ally defines some­thing smal­ler. In a sim­ilar vein I reckon that any attempt to describe the ingenu­ity of the Anti­kythera Mech­an­ism actu­ally ends up describ­ing some­thing less ingeni­ous instead. More research on the device has been pub­lished recently in the Journal for the His­tory of Astro­nomy. I real­ise that people might be drop­ping on to this entry from a search engine, without hav­ing read any of the earlier posts, here’s a quick recap of what the mech­an­ism is.
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