What the scientists are saying...
Has the Moon got a sibling?
An asteroid spotted behind Mars could be the Moon’s long-lost “sibling”, scientists have claimed. The two-kilometre-wide body is a “Trojan” – a celestial object that shares a stable orbit with a larger body. This one is trapped in a “Lagrange point”, an area where the gravitational pull of two large bodies (Mars and the Sun, in this case) cancel each other out. It was first spotted 22 years ago, but astronomers have now examined it using data from the Very Large Telescope, in Chile’s Atacama desert – and found it looks remarkably like the Moon. “We looked at how it reflects light from the Sun... and what’s interesting is that the colour is more similar to the colour of the Moon than the colour of all other asteroids,” said Dr Apostolos Christou, of the Armagh Observatory and Planetarium in Ireland. The scientists speculate that the asteroid could be a shard of the Moon that was flung into space billions of years ago, when the Moon collided with another body. But they stress that this is just one hypothesis: the asteroid could also be a fragment of Mars itself.
A weed that might fight cancer
A common roadside weed has been found to halt the growth of breast cancer, reports The Times. A member of the cabbage family, Arabidopsis thaliana – also known as mouse-ear cress or thale cress – is found on verges and waste grounds across Europe and Africa. When Prof Alessandra Devoto, a plant biologist at Royal Holloway, University of London, began exploring its medical properties more than a decade ago, colleagues were sceptical: the plant has a very simple molecular structure, and was thought to have limited potential. But in lab tests, she appears to have proven them wrong. When leaves of the plant, treated with a hormone found in jasmine, were incubated with cell cultures from breast cancer, the cancer cells stopped growing, while those from healthy tissue were unaffected. “The plant is very much like the Cinderella of the medicinal plant world – no one thought it was so special, but it has shown its true colours,” she said. She hopes the plant could be used as the basis for new chemotherapy drugs with fewer side effects than existing ones.
New hope for Covid immunity
How long are those who catch Covid-19 likely to be protected against reinfection? A study last month, which found that antibodies wane “quite rapidly”, raised fears that immunity is short-lived. But now a study looking at an alternative source of immunity – so-called memory T-cells – has given grounds for more optimism. Researchers found that 100 NHS workers who were diagnosed with the disease in March or April still had detectable T-cell levels six months later, even when antibodies were no longer detectable. T-cells are specialist “destroyer” cells produced by the immune system, which work alongside antibodies to repel invading pathogens. When the pathogen is eliminated, most T-cells die, but a proportion live on, retaining a “memory” of the invader, and can trigger a response if they encounter it again. It remains unclear whether memory T-cells on their own can fully protect against Covid-19 reinfection. However, study coauthor Prof Paul Moss, of the University of Birmingham, described the findings as “reassuring, potentially even encouraging”.
A paint to keep buildings cool
Painting buildings white could help tackle climate change by eliminating the need for air-conditioning. “Heat-rejecting” paints, which reflect sunlight, have long been touted as a way to reduce the energy expended on cooling buildings. Most commercial versions, however, have turned out to be pretty ineffective: when applied to the outside of homes and offices, they don’t reflect enough sunlight to reduce the temperature inside. But now, engineers in the US have developed a new paint, consisting of a high proportion of calcium carbonate, which, they say, greatly enhances its sunlight-reflecting properties. In tests, it has been found to reflect 95.5% of sunlight, and to keep surfaces up to 10°C cooler than their ambient surroundings. “Your air-conditioning kicks on mainly due to sunlight heating up the roof and walls,” said Joseph Peoples of Purdue University, a member of the team which developed the paint. “This paint is basically creating free air-conditioning by reflecting that sunlight.”