Owls sing to the moon

Eagle owls use the moon to talk to one another at night, according to a European team of researchers. They found that Eurasian eagle owls (Bubo bubo) call more on moonlit nights, when the moonlight illuminates the white patch of feathers they expose only when calling out loud.

The  owls rely mostly on a vocal call to communicate, but drive home the message with a flash of white feathers. The owl’s call, together with the bright white feathers, makes them rather noticeable in the dark of the night.

Eagle Owls: wolves in owl's clothing? Image: Hypothesis Now

The owls also favour higher perches on moonlit nights, presumably taking advantage of the more exposed position to make the most of the light shining on their stark white feathers. In contrast, the owls were often silent on moonless nights and, if they did call, the owls tended to do so from a lower perch.

Many animals alter their behaviour depending on the phases of the moon. Usually, bright nights make it easier for predators to find prey, so small animals keep quiet when the moon is full. Eagle owls, however, have no natural predators so they’re free to make themselves as eye-catching as possible to ensure nearby owls get the message. They usually communicate most at dusk and dawn, but a full moon produces almost as much light and the owls have learned to take advantage of it to call long into the night.

It may sound obvious, but the point of signalling is to be understood, and animals have evolved lots of clever tricks to get their messages across: many other birds have repeating calls, so the message is repeatedly broadcast; Anole lizards bob their heads to make themselves stand out from the background; and poisonous insects often use bright contrasting colours to warn off prospective predators. The eagle owls have simply learned to take advantage of another source of light.

Paper reference: Penteriani, V.,  Delgado, M.d.M.,  Campioni, L.,  Lourenço, R. (2010) Moonlight Makes Owls More Chatty. PLoS ONE 5(1): e8696. doi:10.1371/journal.pone.0008696

‘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

Moon Shots

The Apollo 14 landing site.

This picture, taken last week by NASA’s Lunar Reconnaissance Orbiter, shows the site of the Apollo14 moon landing. As far as I’m aware, these are first ever detailed images of the Apollo landing sites, and they only represent a rough test of the imaging capabilities of NASA’s latest lunar mission. Future images should be impressive indeed!

Visible across the centre of the picture are the tracks left by the astronauts as they walked between the Apollo 14 lander on the right (see that small rectangular shadow?) to a small pile of equipment on the left. If it’s not obvious, I’ve included the magnified and annotated version, below.

See it yet?

The NASA Lunar Reconnaissance Orbiter (LRO) website includes images of the other Apollo landing sites, including Apollo 11.

These images are only a taste of things to come. The LRO hasn’t yet reached its final position in orbit around the moon. When it does so in August, it will be able to take much more detailed pictures to help NASA find landing site and identify valuable resources – both vital if we are ever to return to the moon.

Credit for both images is (of course):  NASA/Goddard Space Flight Centre/University of Arizona