What the scientists are saying…
The shifting “Goldilocks zone”
In the search for signs of extraterrestrial life, astronomers have honed in on planets which, like Earth, orbit in a “Goldilocks zone” around their star – where conditions are neither too hot, nor too cold, for water to exist on their surface. On this basis, it has been suggested that there are at least 300 million habitable planets in our galaxy alone. But according to researchers at Nasa’s Goddard Space Flight Centre in Maryland, this figure is likely to be a vast overestimate. This is because it assumes that all Goldilocks zones are stable, when in fact they are not: they can shift as the star brightens or dims, meaning that planets can fall in and out of them. Now scientists think that between a third and three-quarters of planets in habitable zones are actually Belatedly Habitable Zone planets: they are in a habitable zone now, but originated outside it – when conditions were either hotter, so any water they may have had is likely to have burned off, or colder, so their water could be locked in glaciers that will not thaw. “If life cannot exist on these planets, it might have major implications for the abundance of life in the universe,” study author Dr Noah Tuchow told the New Scientist.
Sleeping pills linked to dementia
Older people who regularly take prescription sleeping pills are more likely to be diagnosed with dementia, a study has found. Researchers from the University of California-San Francisco recruited 3,068 people with an average age of 74, none of whom had dementia. They surveyed them about their sleeping habits and drug use, and followed them for about nine years. By the end of the study, more than 20% had dementia. White participants, who made up 58% of the total, were far more likely than their black counterparts to take sleeping pills. And those who took them “often” or “almost always” had a 79% increased risk of dementia. No such link was found for the black participants. Lead author Dr Yue Leng stressed that the study does not show that sleeping aids cause dementia; it might be the “use of sleep medications is an indicator of something else” that links to an increased risk of it.
The Vikings came with their dogs
When the Vikings sailed across the North Sea to Britain in the ninth century AD, they didn’t travel alone: their dogs and horses made the voyage too. Archaeologists analysed bone fragments found at a Viking burial site in Derbyshire, and found levels of strontium isotopes consistent with the animals having spent most of their lives in Scandinavia. A natural element found in rocks, strontium ends up in soil and plants and thus makes its way into animal teeth and bones; but it exists in different ratios around the world, depending on the local geology, making it a useful geographical marker. The fragments, from a horse, a dog, and possibly a pig, were found alongside human remains in the cremation cemetery. The dog and the horse could have been cremated with their owner, for use in Valhalla; the pig bone may have been imported as part of an amulet.
Loyalty cards to detect cancer
In cases where ovarian cancer is diagnosed at stage one, almost 95% of patients are still alive five years later. But the odds of survival fall rapidly for later diagnoses – and the cancer is one of the harder ones to detect early. Now, though, researchers have found a novel mechanism for identifying cases sooner: supermarket loyalty-card data. Symptoms of ovarian cancer include abdominal pain, bloating and appetite loss. These can all be caused by far less serious ailments, and women who experience them may not think to consult their GP. But they may buy over-the-counter treatments, which is where the cards come in. For the study, led by a team at Imperial College London, researchers recruited almost 300 loyalty card users, more than half of whom had been diagnosed with ovarian cancer, and looked at the retailers’ data to analyse their shopping histories. In a report in the BMJ, they explain that this revealed a “noticeable increase in purchases of pain and indigestion medications among women with ovarian cancer up to eight months before diagnosis”. More extensive studies are needed to verify the findings, but the authors hope it will be possible to use such data to create an alert system that would urge women to consult their GPs if they appear to be suffering from possible ovarian cancer symptoms.