Poor Mojo's Newswire

AT 10.23 am on 30 January, more than 300 activists in the UK, Canada, Australia and the US will take part in a mass homeopathic "overdose". Sceptics will publicly swallow an entire bottle of homeopathic pills to demonstrate to the public that homeopathic remedies, the product of a scientifically unfounded 18th-century ritual, are simply sugar pills. Many of the sceptics will swallow 84 pills of arsenicum album, a homeopathic remedy based on arsenic which is used to treat a range of symptoms, including food poisoning and insomnia. The aim of the "10:23" campaign, led by the Merseyside Skeptics Society, based in Liverpool, UK, is to raise public awareness of just exactly what homeopathy is, and to put pressure on the UK's leading pharmacist, Boots, to remove the remedies from sale. The campaign is called 10:23 in honour of the Avogadro constant (approximately 6 * 10^23, the number of atoms or molecules in one mole of a substance), of which more later.

Wild crows can recognise individual human faces and hold a grudge for years against people who have treated them badly. This ability – which may also exist in other wild animals – highlights how carefully some animals monitor the humans with whom they share living space. Field biologists have observed that crows seem to recognise them, and a few researchers have even gone to the extreme of wearing masks when capturing birds to band (or "ring") them, so that they could later observe the birds without upsetting them. However, it was unclear whether the birds distinguish people by their faces or by other distinctive features of dress, gait or behaviour. To find out, John Marzluff at the University of Washington in Seattle and colleagues donned a rubber caveman mask and then captured and banded wild American crows. Whenever a person wearing the same mask approached those crows later, the birds scolded them loudly. In contrast, they ignored the same person wearing a mask of former US Vice-President Dick Cheney, which had never been worn during banding. "Most of the time you walk right up to them and they don't care at all," says Marzluff.

Scientists have found a striking similarity in the DNA that enables some bats and dolphins to echolocate. A key gene that gives their ears the ability to detect high-frequency sound has undergone the exact same changes over time in both creatures. The researchers report their findings in the journal Current Biology. It may be the first time that identical genetics has been shown to underpin the evolution of similar characteristics in very different organisms.

Now one theoretical physicist is proposing a radical new way to look at gravity. Erik Verlinde of the University of Amsterdam, the Netherlands, a prominent and internationally respected string theorist, argues that gravitational attraction could be the result of the way information about material objects is organised in space. If true, it could provide the fundamental explanation we have been seeking for decades. Verlinde posted his paper to the pre-print physics archive earlier this month, and since then many physicists have greeted the proposal as promising (arxiv.org/abs/1001.0785). Nobel laureate and theoretical physicist Gerard 't Hooft of Utrecht University in the Netherlands stresses the ideas need development, but is impressed by Verlinde's approach. "[Unlike] many string theorists Erik is stressing real physical concepts like mass and force, not just fancy abstract mathematics," he says. "That's encouraging from my perspective as a physicist." . . . Verlinde's work offers an alternative way of looking at the problem. "I am convinced now, gravity is a phenomenon emerging from the fundamental properties of space and time," he says. To understand what Verlinde is proposing, consider the concept of fluidity in water. Individual molecules have no fluidity, but collectively they do. Similarly, the force of gravity is not something ingrained in matter itself. It is an extra physical effect, emerging from the interplay of mass, time and space, says Verlinde. His idea of gravity as an "entropic force" is based on these first principles of thermodynamics - but works within an exotic description of space-time called holography.