Great news... Decoding the Heavens has been shortlisted for this year's Royal Society Prize for Science Books - described as the world's most prestigious awards for science writing.

The judges said about it: "This is a rattling good detective story exploring a subject that we were amazed that we hadn't heard more about.  Learning about the extraordinary capabilities of the ancient civilisations was fascinating and left us all wondering what other incredible pockets of knowledge have been lost at the bottom of the sea or otherwise forgotten."

As would be expected there are some fantastic other books on the shortlist - looks like an even split between three US academics and three UK journalists and biographers. I've pasted the rest of the line-up below, in case anyone's looking for some stimulating summer reading.

What the Nose Knows: The science of scent in everyday life by Avery Gilbert (Crown Publishers).
The judges said: "One of the things you really appreciate about this book is the feeling that you are in the presence of someone who really knows the subject.  He's worked in the fragrance industry and in academic research and engagingly leads you into his fascinating world.  Since reading this book we've all thought more about the scents around us and our oft-neglected sense of smell."


Bad Science by Ben Goldacre (Harper Perennial).
The judges said: "We found this book was funny, accessible and offered much more than just a collection of Ben Goldacre's excellent columns in the Guardian.  He attacks and debunks pseudoscience, which is really vital given how much is out there and how important the issues are to our lives.  There's more to be said about some of the subjects, like the MMR vaccine scandal, and we're looking forward to the sequel."

The Age of Wonder: How the Romantic generation discovered the beauty and terror of science by Richard Holmes (HarperPress).
The judges said: "We all thought this was a fantastic, enlightening and inspiring book, taking characters from the history of science and making them come alive. Richard Holmes has managed to seamlessly merge science, social history and literary history in a wonderful narrative, putting science in a wider context and producing a truly enthralling read."

The Drunkard's Walk: How randomness rules our lives by Leonard Mlodinow (Penguin).
The judges said: "This book is well-written, enlightening and very funny at times.  We could see people reading it and finding their perspective of odds and probability being fundamentally altered - it definitely puts you off buying a lottery ticket or having a gamble on the roulette wheel!"

Your Inner Fish: The amazing discovery of our 375-million-year-old ancestor by Neil Shubin (Penguin).
The judges said: "This is a charming and delightful book; not often that a science book can be described in such terms!  The author, an expert palaeontologist with a deep understanding of anatomy and animal development, still manages to explain things clearly, gracefully and eloquently - we all felt he'd be a great person to meet in the pub for a chat and a drink!"

Could a mysterious coating on the Parthenon have come from outer space? Don't worry, I'm not about to tell you about some crazy theory of alien technology coming to Earth. Instead it's a possible solution to a problem that has stumped scholars of ancient Greek temples for a couple of centuries.

Last week I wrote about how researchers have detected the first traces of pigment on sculptures from the Parthenon in Athens. For the ancient Greeks, the temple would likely have been not plain marble, but a veritable explosion of red, white, blue and gold.

Since the 19th century however, archaeologists have been arguing about the significance of an orange-brown coating on the temple's stone (much of which has since been cleaned off). Similar colouring is also seen on other ancient temples in the Mediterranean region. Was this simply the result of natural weathering? Or had the Greeks used some kind of varnish to tone down the bright white of the stone, making the buildings a little easier on the eye in bright sunlight (the Greeks didn't have the benefit of polarising sunglasses after all).

Ian Jenkins, senior curator at the British Museum in London, with responsibility for the Parthenon sculptures that are held there, says the coating seems to have been applied once, rather than building up gradually over time. The coating itself has been subject to some weathering, and where it has been damaged in the past it doesn't seem to form again.

This has been used to support the idea that the colouring was applied by the Greeks, but Jenkins has an intriguing alternative theory. The coating must be due to a one-off event in antiquity, he says, that happened after the temple was constructed in the 5th century BC. But that doesn't mean it was man-made.

Jenkins points out that oxalate minerals found in the coating suggest a biological origin, and he believes the event in question occurred in 536 AD, during what has become known as a "year without summer". Historical records say that during this year, dust filled the air and "the sun gave no more light than the moon". Crops failed to grow, and cattle died on their feet. Evidence of this awful time can still be seen today in tree rings from ancient timbers - the growth ring for 536 AD is extremely small.

Climate disruption continued for the rest of the century. Jenkins argues that during these darker, more humid conditions, microbes could have grown rampant on the surface of the stone, leaving behind the orange-brown coating as they decomposed.

The debate about what blocked out the sun is ongoing. In February 2008, Lars Berg Larsen of the University of Copenhagen and colleagues reported a big spike of sulphate in ice cores from both Greenland and Antarctica, that was laid down around 536 AD. This suggests much of the planet was covered in an acidic dust veil, which they concluded was due to gigantic volcanic eruption.

But in January 2009, Dallas Abbott of Columbia University's Lamont-Doherty Earth Observatory in New York and colleagues reported that they had found tiny balls of condensed rock vapour inside Greenland ice cores dating back to early 536 AD. They reckon these come from terrestrial debris ejected into the atmosphere when a comet (probably in several pieces) smashed into the Earth.

I don't know if Jenkins is right or not about the temple coatings - if anyone knows any more about this please let me know. Either way, to leave its mark all the way from the north pole to the south, this must have been one hell of a disaster.

Today, the Parthenon temple that watches over Athens is a pure, white building, dazzlingly bright on sunny days against the deep blue sky. But it wouldn't have looked anything like this in ancient Greek times. Researchers at the British Museum announce today that they have detected tiny traces of blue paint on the building's sculptures - suggesting that the temple's statues and friezes would have been not stark white, but a riot of colour.

I've just written a short story on the work for New Scientist, which you can read here. Although only a few hints of a pigment called Egyptian blue have been detected so far, experts think that the original paint job would have included red as well, with the original marble showing through white in places, and highlights of gold in others (see second pic below for one interpretation of what this might have looked like). Although we have the benefit of seeing the sculptures on display at eye level, for the ancient Greeks they were fixed around the top of the temple - 40 feet high. "Colouring would have hugely enhanced the visibility," says senior curator Ian Jenkins, who is responsible for the Parthenon sculptures held at the British museum.

Scholars have long known that the Greeks painted their marble buildings and statues, but they're particularly excited about this work because despite two hundred years of searching it hasn't been seen before on the Parthenon's sculptures (there used to be some visible traces on the mouldings just underneath the roof, but not on the sculptures themselves). In the end, post-doc Giovanni Verri used a clever imaging technique called photo-induced luminescence to pick up microscopic specks of pigment. When red light is shone onto the molecules of Egyptian blue, they absorb it and emit infrared light. Seen through a camera sensitive to infrared, any parts of the marble that were once blue appear to glow.

So far Verri has found the blue in a few different places - for example on the belt of the messenger goddess Iris from the temple's west pediment (see the pic below from the British Museum - there's a normal photo on the left, and an infra-red image showing Iris's glowing belt on the right). Depicted as she descends to earth, she's famous for her life-like flapping tunic. Verri also detected blue stripes on a cloak draped over the knees of the goddess Dione, from the east pediment. It's amazing to think that when in full colour, the Parthenon's sculptures showed details down to the weave pattern of a figure's clothing.

One thing that interests me, though, is why the public perception of Greek temples and sculptures is of simple white buildings, when there's so much evidence that they were actually brightly coloured. I asked Jenkins about this and he described it as "a conspiracy of collective amnesia".

"We don't want to know it," he says. "We want to believe that ancient sculpture was white and pure." He believes that instead of paying attention to how the Greeks really lived, we're judging them according to our own aesthetic standards - for example the idea that it would be abhorrent to cover up beautifully-carved quality marble with coloured paint. He thinks the delusion stems from the Renaissance - when artists producing sculptures inspired by those of ancient Greece left them white to dissociate them from the previous Gothic style.

Jenkins also told me of his intriguing theory that the Parthenon's colour was affected by a severe climate disruption which caused a "year without summer" in the sixth century AD. I'll write about that in the next post...