What the scientists are saying…
A super-fast trip to Mars
When Nasa’s Orion spacecraft headed back to Earth last month after its trip around the Moon, it was travelling at almost 25,000 miles per hour; that is quite fast if the Moon is your destination, reports The Washington Post – but rather slow if you need to make the 300 million miles or so journey to Mars. Using current technology, it would take astronauts seven months to get to the Red Planet, which is just too long. It’s too long to spend on a cramped spacecraft, and it would also expose the crew to dangerous levels of cosmic radiation. If Nasa is to get to Mars, it needs to get there faster – which is why it has now unveiled plans to build a nuclear-powered rocket that could halve the journey time, an idea first mooted decades ago, but which was abandoned in the 1970s. A nuclear thermal rocket engine uses a fission reactor to generate extremely high temperatures; this heat is then transferred to a liquid propellant, which is expelled through a nozzle to accelerate the spacecraft. The engines are likely to be used initially for trips between Earth and the Moon. Shortening these journeys would assist efforts to develop Moon bases as staging posts for eventual journeys to Mars. Nasa, which has partnered with a defence agency for this project, says it aims to demonstrate the technology in 2027.
Even a bad marriage can be good
Living with a partner might be good for your health – even if you are not happy together, a study has found. Researchers examined the health records of more than 3,300 people (all of whom were over 50) who had signed up to The English Longitudinal Study of Ageing, and looked at data on several factors, including body mass index, rates of depression, and social relationships, as well as their results in HbA1c tests – reliable indicators of average blood-sugar levels. They found that being married or cohabiting was associated with lower blood-sugar levels, regardless of the quality of the relationship; and that when people left a relationship, their levels changed significantly. The study was only observational, but it could be that when people are cohabiting they make more effort to eat healthily, and with shared overheads, have more money to spend on healthy food. The researchers said that to protect people in this age group from type 2 diabetes, it would be a good idea to address the “barriers that impede the formation of romantic partnerships” in older people.
Pollution linked to depression
Airborne pollution has been associated with a host of health conditions, from dementia to heart disease; now, a study has found a link between it and poor mental health. A team from Beijing, Oxford, and Imperial College London examined data on more than 389,000 adults taking part in the UK Biobank Study. They found that the 25% of participants whose homes were in areas with the highest levels of pollution were 16% more likely to suffer from depression or anxiety over the 11-year study period than the 25% exposed to the lowest levels of pollution at home – even after taking into account factors such as socioeconomic status. A separate study published in the journal PLOS One, and involving more than 3,200 children at schools in London, found a link between long-term exposure to high levels of PM2.5 particles and higher blood pressure in teenagers. For girls, a 1μg/m3 increase in PM2.5 was associated with a 1.34 mmHg increase in systolic blood pressure, on average; for boys, the rise was 0.57 mmHg.
A marsupial’s fatal attraction
The male northern quoll – an Australian marsupial that is about a foot long – tends only to survive one breeding season, whereas females usually live for four. Now researchers have found out why: in its determination to mate, the animal exhausts itself to death. Using sensors to track northern quolls, the team observed that the males travelled more than six miles in a night in search of a partner, resting for only 8% of the time. The males had more parasites than females, probably because they prioritised seeking a mate over grooming, and were not as vigilant about searching for food and avoiding predators. “By the end of the breeding season, these quolls just look terrible,” said study co-author Dr Christofer Clemente, of the University of the Sunshine Coast.