Ancient greek worshippers looked to the sun

The classical Greek gods were many and varied, with each representing some aspect of nature or of the human psyche, but it seems they all shared one common feature: from wise Athena to morbid Hades, they all preferred their Earthly temples to face the rising sun.

Look to the east - Greek temple ruins on Sicily. Image: Flickr/Chiara Marra

A British researcher has used simple statistics to show that a significant number of temples built on the island of Sicily by Greek colonists, and many of those found on mainland Greece, face east. The results are the first time anyone has shown Greek temples tend to look towards the sunrise.

Understanding an ancient religion can tell us much about the society that followed it. But how can we learn about a religion when it hasn’t been practised for hundreds, or even thousands, of years?

All we have are the artefacts that survive the ravages of time, the most conspicuous of which are often mighty stone temples. For a long time, academics have debated whether Greek temples had any common alignment, and in particular whether they were aligned with astronomic events like sunrise on certain holy days.

This latest study measured the alignment of 41 Sicilian Greek temples, and showed 40 of them face the eastern half of the sky. Even when ‘east’ was defined as just the strip of horizon where the sun rises at some time during the year (between 59^o and 119^o in Sicily, apparently), 38 temples still faced east – this is incredibly unlikely to be due to chance alone.

Temples on mainland Greece fare slightly less well, although the results are still significant, with 38 of 42 facing the eastern half of the sky, and 26 of those facing more directly east. The researcher believes mainland Greek temples might have been built over older religious sites, which could affect the alignment chosen by their builders. Sicilian Greeks, who were recent migrants, probably felt no such connection to their adopted home and sited their temples in the direction they preferred – eastward-facing. The Sicilian Greeks may also have been trying to be as ‘Greek’ as possible, to reinforce connections to their homeland.

Precisely why Greeks temples align with the rising sun is still a mystery – the ancient stones can only tell us so much.

The research results are interesting, and they also show how a simple statistical test can aid archaeological and historical studies – disciplines which do not always rely on mathematical techniques for answers. The research demonstrates how the combination of the two disciplines can introduce powerful new techniques to answer previously tricky questions and, in this case, settle old arguments.

Paper Reference: Salt, A. M., (2009) The Astronomical Orientation of Ancient Greek Temples. PLoS ONE 4(11), e7903. DOI:10.1371/journal.pone.0007903

Supervolcano caused global cooling

The supervolcano which erupted 74,000 years ago at Toba in northern Sumatra was the most devastating natural event ever witnessed by humans. Now new evidence has emerged that the blast had long term implications for global ecosystems as it led to many years of drought, caused by a dramatic and prolonged drop in global temperatures.

Beautiful but deadly, and nowhere near the size of the Toba eruption, 74,000 years ago. Image Credit: Flickr/Roberto Zingales

An international team of researchers have shown that the forests which covered India before the volcanic eruption were replaced by open scrubland, and moisture-loving plants like ferns disappeared. The results suggest the global climate became much colder and, consequently much drier, which destroyed forests that depended on warm moist conditions.

To make their discovery, the researchers analysed long vertical sections of soil and marine sediment, called cores. The Toba eruption blew so much ash and rock into the atmosphere that it forms an easily-distinguished layer in soil and sediment cores from much of southern Asia. This meant the researchers could easily identify pre- and post-eruption deposits of soil and sediment and analyse their composition.

The researchers used the ratio of different carbon isotopes found in soil layers deposited before and after the eruption to examine the effect it had on vegetation that grew in India. Different types of vegetation leave different signature ratios of carbon isotopes in the soil because they use different chemical pathways to produce food through photosynthesis. The change in carbon isotope ratio showed that the vegetation changed from lush tropical forest to open scrubland just after the eruption occurred.

They also found much less pollen from ferns, which prefer warm, wet conditions, in marine sediment from after the eruption, suggesting there were far fewer of these plants alive at the time.

The Toba eruption was the most powerful volcanic eruption on Earth in the past two million years, causing temperatures to fall and resulting in massive droughts, which lasted for almost two thousand years!  It’s easy to why scientists have suggested deliberately pumping tonnes of sulphate particles, just like those produced by volcanic eruptions such as Toba, into the upper atmosphere to reduce global temperatures in the face of anthropogenic climate change.

Paper Reference: Williams, M., et al (2009) ‘Environmental impact of the 73 ka Toba super-eruption in South Asia’. Palaeogeography, Palaeoclimatology, Palaeoecology. doi:10.1016/j.palaeo.2009.10.009

‘In a hole in the ground there lived…’

‘…a hobbit.’*

Fossil ‘hobbits’ found on an Indonesian island and reported in Nature in 2004 are a new species after all, according to a new study by American researchers. Statistical analysis of the fossil skulls and limb bones show it did not belong to a diseased modern human, or a pygmy, but a unique species. But haven’t we heard such claims about the ‘hobbits’ before?

H. floresiensis: small, yet distinctive. Image: Wikimedia/Ryan Somma

Yes, we certainly have. The diminutive fossil hominid, found on the island of Flores in 2003 and nicknamed ‘hobbits’ by their discoverers, were at the centre of an international argument. Initially hailed as a new species known as Homo floresiensis, several researchers dismissed the fossils as the remains of diseased humans. Since then, claims and counter-claims have appeared in the scientific literature and the press. This latest study agrees with the well-supported ‘unique species’ hypothesis.

The researchers carried out a statistical analysis of important physical features of the best-preserved H. floresiensis fossil. They found that its skull retained some very primitive features, such as thick bones and primitive teeth. These features do not fit the pattern seen amongst modern humans, pygmies, or people with a rare condition known as microcephaly.

The researchers also examined the shape of other hominid skulls and established the pattern of changes seen as the skulls get smaller. By carrying this pattern downwards to very small skulls, the researchers ended up with something very similar to H. floresiensis, suggesting H. floresiensis was a perfectly healthy member of the great hominid family to which we ourselves belong.

In case that wasn’t enough, the researchers also demonstrated that the body proportions of H. floresiensis were completely dissimilar to modern pygmies. Short (they stood around one metre tall) and stocky, the hobbits resembled no-one alive today.

*From ‘The Hobbit’ by JRR Tolkien, but you knew that, didn’t you?

Paper Reference: Jungers, W., and Baab, K. (2009). The geometry of hobbits: Homo floresiensis and human evolution. Significance, 6(3), 159- 164. DOI: 10.1111/j.1740-9713.2009.00389.x

Liang Bua cave, Flores. A long way from Bag End! Image: Wikimedia/Rosino

The social life of plants

Plants aren’t the first thing most people think of when talking about social interactions. They don’t have the complex social lives of many animals, and have few opportunities to meet new people, yet plants do interact socially. A study by Canadian researchers has shown that plants become much more competitive when they’re growing next to unrelated plants, putting out extra leaves and trying to out-compete their rivals.

Impatiens pallida: recognising the importance of family. Image: Wikimedia/SB Johnny

Researchers have known for a while that plants can recognise other related plants growing nearby. The new study shows that one species of plant, known as Impatiens pallida, actually responds to the presence of ‘family’ by producing fewer leaves and more branches and longer stems. Fewer leaves means less competition for light – suggesting the two plants are cooperating.

In contrast, when I. pallida was grown with an unrelated neighbour of the same species it put much more effort into growing leaves, competing with its neighbour for the available light. The effect was only seen when the two plants were grown in the same pot; without root contact between the plants there was no change in growth. Researchers still don’t know, however, exactly how plants recognise kin.

I. pallida’s response to competition is perfectly adapted to its natural surroundings. It prefers dark, shady spots where light is the only thing limiting the speed at which it can grow. In this case, competition means a battle for the scant available light. The related species I. edentula grows in the open, often on beaches, where there are very few nutrients in the sandy soil. When faced with competition, I. edentula sprouts extra roots, to extract as much as possible from the soil to give itself a boost.

In animals, a lot of cooperative behaviour is seen between close relatives (think of prides of male lions, who are usually brothers, or massive ant colonies – which contain mostly sisters and mothers). Relatives share many similar genes, so by helping brothers and sisters reproduce, an individual can ensure at least some of their own genes are passed on to future generations. Unrelated individuals share fewer genes, so there’s no reason to cooperate. This is known as kin selection, and is a powerful driving force for altruistic behaviour – in both plants and animals!

Paper reference: Murphy, G., and Dudley, S., (2009) Kin Recognition: competiton and cooperation in Impatiens (Balsaminaceae). American Journal of Botany, 96(11).  1990–1996. DOI:10.3732/ajb.0900006

‘Buckets’ of water found on moon

NASA scientists have found large quantities of water in the debris thrown up by the LCROSS spacecraft, which was deliberately crashed into the moon last month.

The lunar south pole, perfect place for an (indoor) swimming pool? Image credit: NASA

The finding tells us much about our nearest neighbour, and its potential role in space exploration: the presence of water ice on the moon is vital for future lunar exploration. It could supply drinking water, oxygen and rocket fuel, which opens up the possibility of permanent lunar settlement.

LCROSS, which stands for Lunar CRater Observing and Sensing Satellite, slammed into the Cabeus crater at the moon’s south pole. The bottom of the crater never sees sunlight and is the ideal place to look for hidden water ice, which may have lain undisturbed for the past billion years. LCROSS hit the crater floor in two stages: the first was the expended upper stage rocket, called Centaur, used to get the spacecraft into position for its collision. Following close behind was LCROSS itself. LCROSS was loaded with cameras and spectrometers to record the results of the first impact before it too hit the lunar surface four minutes later.

Although it perhaps wasn’t the most elegant experiment ever conducted, it seems to have achieved all its designers hoped for. Data from spectrometers aboard LCROSS confirmed the presence of water in the material thrown up by the impact. Spectrometers look at the light emitted or absorbed by a substance, as this gives a clue as to what it is made of. The LCROSS data contained the unmistakable signature of water. And it wasn’t just a trace of water: the scientists believe the signal corresponds to around 100kg of water (or ‘a dozen two-gallon buckets’, according to one researcher on the BBC), suggesting there is more than the occasional frozen puddle to be found in the dark corners of the moon.

Many people were disappointed with the initial results of the LCROSS mission. The 2,200kg spacecraft was expected to create a plume of material around ten kilometres high and visible from Earth as it was illuminated by the sun. Instead, the plume was much smaller, only reaching one and a half kilometres above the lunar surface. This was still enough to advertise the presence of water to the cameras on LCROSS.

See the little grey blob? Thats the plume of dust and ice. Unimpressive, perhaps, until you notice the scale bar! Image credit: NASA

Judging a book by its odour

The smell of a book is important, able to bring to mind memories of times and places long gone. It is often associated with the thrill of immersing oneself in a new book, or exploring an ancient, dusty tome in a library. Yet the smell of an old book can do more than just bring back memories: scientists have developed a way to analyse book smells to find out about the condition of old books, allowing them to work out how best to preserve them.

I can almost smell the knowledge these contain... Image: Flickr/Brian Negin

A book’s smell changes with age, as the materials it’s made from degrade. Paper, glue, stitching and leather all release characteristic organic molecules as they break down, and it is the combination of hundreds of these volatile organic compounds (or VOCs) that create that distinctive book smell. By measuring the amount of each VOC present, the scientists can identify what the book is made from and how degraded it is. This is the first time scientists have been able to link the smell of a book directly to its condition.

Old paper contains many different substances. Some of these, such as a substance called rosin, break down relatively quickly and release acidic chemicals, rendering old books unreadable. Another, lignin, turns yellow with age, which makes old books and newspaper clippings hard to read.

The new findings could be used to develop a non-destructive test to help identify the state of ancient manuscripts, which will help museums and libraries preserve them. Being able to quickly and easily identify what a book is made of and what chemicals are causing the most damage could help museum and library curators save documents which might otherwise be lost. At-risk books could be moved to a controlled environment, which can slow down the ageing process and preserve the book for as long as possible.

Until now, it was impossible to know what condition the book was in without removing a sample of its paper for testing, which damaged the book even further – not ideal when trying to preserve priceless historical documents!

Paper reference: DOI: 10.1021/ac9016049

Darwin and the Devil’s Garden

Science is strewn with controversial ideas and contradictory opinions. Eventually, one side or another in the debate is usually proved right, and science advances. Sometimes, very occasionally, it turns out both sides are right. The story of the ants and their tree-houses is one such occasion.

The Amazon Rainforest - here there be devils? Image: NASA

It starts, as so many evolutionary biology stories do, with a certain Charles Darwin. He observed that many ant species inhabit cosy little nodules, called domatia, on the branches of tropical trees. The ants kill any other insects that land on the tree, protecting the tree from harm. They also, in some cases, inject deadly formic acid into any other plants that take root in the area around their home tree, killing off any competitors before they can become established. This land-clearance leads to the formation of ‘devils’ gardens’ in tropical rainforests – area of forest where only one species of tree (called Duroia hirsuta), which houses the ants, can grow. In return for their diligent defence, the ants get safe lodgings in the tree’s specially-grown domatia. It’s a perfect example of ‘mutualism’, where both parties benefit from cooperation. At least, that’s how Darwin saw it.

Richard Spruce, a contemporary of Darwin, disagreed. He thought the ants were parasites, taking over trees and boring their own tunnels, which eventually produced the characteristic domatia as the tree responded to the damage the ants caused. The trees gained nothing from the relationship, and were powerless to stop the ants burrowing deep into their living tissue.

In the 1960’s, scientists showed that Darwin was right – the trees deliberately grow the nodules for the ants to inhabit, suggesting the relationship had mutual benefits for both tree and ant. Case closed, you may think. Well, not quite…

Recent research by a team of UK and American scientists has shown that some ants do in fact build their nests inside trees which do not grow welcoming domatia. The scientists were tipped off by local people, who found some unusual scars on nearby tree trunks. It turned out that the ants, known as Myrmelachista schumanni or lemon ants , build nests in domatia-free trees on the edge of the devil’s garden they have created, possibly as a result of overcrowding of their original tree-house homes.

So it turns out Spruce was also correct – the ants do parasitize some trees, digging out new homes in their trunks and branches, which has no benefit for the tree.

And the moral of our tale? Science is constantly changing, and there are few, if any, absolutes. For me, this is precisely what makes it so interesting: the constant search for knowledge of the natural world throws up many unexpected nuggets of information, and who knows what established ‘truth’ will be overturned next week?

Paper Reference: doi: 10.1086/606022

Do you have one arm longer than the other?

If you’re right-handed, you may think so. Research by an American team has shown that right-handed people think their right arm is longer than their left, despite them both being the same size!

Image credit: Hypothesis Now

The differences in perception correlate with the level of activity in the ‘arm’ regions of our brains: right-handed people show much more neural activity over a larger area in the region associated with their right arm than with their left. In contrast, left-handed people show no difference between their two arms: the area of brain activity for both tends to be equal in size.

These results are the first time anyone has shown that our perception of our body can be influenced by the body ‘maps’ our brains create.

Using a limb more often can cause the brain area related to it to increase in size. Left-handers often use both arms equally, whereas right-handers tend to favour their right arm for the vast majority of tasks. The researchers wanted to see if the uneven brain activity in right-handers matched how people actually perceive their body shape, regardless of how long their arms actually were!

To do so, they asked volunteers to estimate how long their arms were and how far they could reach to pick up an object. Volunteers were asked to hold one arm out-stretched in front of them. The researchers then held up a tape measure, with the numbers hidden, and asked the volunteers to tell them when the tape measure was the same length as their arm. They then asked volunteers to tell them when they thought a small object was within their reach as the researcher slowly slid it across a table towards them.

Left-handers thought their arms were of equal lengths, and that they could reach just as far with both hands. Right-handers, however, had a significant difference between the perceived lengths of their arms, consistently thinking their left arms were much shorter than their right and couldn’t reach as far.

The researchers are careful to point out that the unevenly-sized areas of neural activity might not actually cause the perceptual differences: someone needs to do a bit more research to establish exactly what causes this bizarre phenomenon!

Paper reference: doi:10.1111/j.1467-9280.2009.02447.x

Dinosaur extinction continues in lab

Evolution results in the formation of many species from a single ancestor, but what could possibly result in the formation of one species from several others? The answer is simple mis-labelling, according to a recently-published study of dinosaur skulls.

Dracorex hogwartsia: such an odd-looking child... Image: Flickr/Roger Lynn

According to the study, researchers may have wrongly identified juvenile dinosaurs of one species as two completely different species. The results mean we could see the extinction (again!) of many other supposed species of dinosaur, as they are also found to be the young of other dinosaurs.

The confusion arose because the skulls of the dinosaurs, which are often used to tell species apart, change dramatically as they age. The dinosaurs being studied were pachycephalosaurids, famous for their heads covered in horns and lumps and crowned by spectacular bony domes – which were used, as birds use their feathers today, to advertise sexual maturity and to allow the dinosaurs to identify members of their own species. Young Pachycephalosaurus had no domes, and their horns were arranged differently to the adults, leading researchers to name the young dinosaurs as entirely different species.

The new study looked at sections of bony skull from three pachycephalosaurid ‘species’ under a microscope and found they were made of bone which changed shape dramatically over the dinosaur’s life time. Similar shape-shifting bone has been found before in dinosaurs like the famous Triceratops, whose three curving horns grow from the same substance. As Triceratops aged, its horns twisted and turned until they reached their adult form. A similar re-shaping of skull bones as the animals matured is thought to have led to the pachycephalosaur confusion.

So what does this mean for palaeontology? As well as the loss of the two pachycephalosaur species, the researchers think it could result in even more species being recognised as the young of others, particularly amongst other dinosaur species in the group known as marginocephalians, which includes animals such as Pachycephalosaurus and Triceratops.

The species lost in this case include Dracorex hogwartsia, named for Hogwarts School in the Harry Potter children’s books, and Stygimoloch spinifer. Both are thought to be juvenile Pachycephalosaurus wyomingensis, from the Upper Cretaceous period of North America.

Paper reference: doi:10.1371/journal.pone.0007626

Born to drive (badly)

Could bad driving be blamed on our genes? Volunteers with a certain gene variant did much worse on a driving task than those without the variant, according to an American study. The result is rather surprising: our brains are tremendously complicated and the researchers didn’t think a single gene could have such a dramatic effect on behaviour.

"166 mph on the wrong side of the road, Officer? Sorry, it's my genes..." Image credit: Flickr/TrickyTM

The study suggests the gene in question helps people learn new physical tasks, such as driving along a complicated route, and remember how to complete the tasks in future. It works by producing a protein called BDNF, which helps neurons in the brain communicate with one another. Concentrating on something causes your brain to produce more BDNF in the brain region doing the thinking, letting it work more efficiently. People with the gene variant produce less BDNF so they don’t get this boost to brain power.

To test the variant’s effect on learning a complicated physical task, the researchers asked volunteers in a driving simulator to drive laps around a track. Those with the gene variant made more errors than volunteers without the gene variant. They also did badly when they repeated the task four days later.

So why have we evolved a gene variant that seems to make learning harder? It turns out the variant of BDNF does have one major advantage – people with it keep their mental abilities longer if they’re affected by diseases such as Parkinson’s, which damages brain function. Our brains, it seems, can be either very resilient to damage or very flexible when faced with learning and change, but not both.

Paper reference: doi:10.1093/cercor/bhp189