What the young can give to the old - The Economist   

Paul Bert, a pioneering 19th-century French physiologist, added a gruesome new procedure to laboratory experimentation: grafting mice together rather as a gardener grafts branches onto a tree. Part of the idea was to discover what qualities could be passed from one mouse to the other through the blood they now shared. In the 1950s such “parabiosis” experiments led to the suggestion that one such thing was youth. Older rats, after several weeks grafted to younger rats, showed signs of rejuvenation.

The experiments were widely ignored until new interest in the science of ageing brought them to light in the 2000s. Since then the phenomenon has attracted new interest among both scientists and a number of people who might charitably be described as chancers. Young-to-old transfusions of human blood plasma allow wealthy clients to take a punt on the blood of hard-up students.

There may be substances in young blood that help the old, such as taurine or humanin. However it seems quite likely that the effect seen in older rats owes more to the removal of detritus than an influx of the essence of youth. In 2020 Irina Conboy of the University of California, Berkeley, and her colleagues found that replacing half of an old mouse’s blood with just albumin, a blood protein, and saline solution had the same rejuvenating effect as young-mouse blood. Old blood may need filtering and dilution, not supplementing.

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Some claim human lifespans can be lengthened indefinitely - The Economist   

There is a story about a blues musician who, when questioned on his 100th birthday about his decades of smoking and drinking, responded that if he’d known he was going to live so long, he’d have taken better care of himself. Bryan Johnson is that apocryphal bluesman’s polar opposite. He has been taking care of himself for years to a degree as remarkable, in its way, as the deepest devotion to bourbon and bad choices. By sacrificing the now for the future, rather than the other way around, he turns disposable-soma theory on its head.

The daily regime which he and his many doctors have devised makes life in Biosphere 2 look sybaritic. A kilogram of vegetables, all before 11am, rigorous workouts lasting 45-60 minutes, and 100 pills, including metformin and rapamycin. His vital functions are subjected to the sort of continuous scrutiny more usually associated with laboratory animals. He says he is ageing at 69% of the normal rate.

Mr Johnson, who has been described as the most measured man in the world, can afford the team of medics, trainers and dieticians who minister to him because selling Braintree, an electronic-payments company which he founded, left him with a net worth of more than $100m. For mere mortals, however, a range of less intensive options are available.

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How scientists went to an asteroid to sample the Sun - The Economist   

It was, Dante Lauretta told his audience at an American Geophysical Union meeting in San Francisco, like seeing an old friend after “seven years [and] a journey of 3bn miles”. Sitting in front of him in the Utah desert on the morning of September 24th, “a little charred and worse for wear”, was a capsule about the size of a washing-machine drum. The last time he and his colleagues had seen it had been when they had packed it up ready to be launched into space from Cape Canaveral in the summer of 2016.

In the intervening years the capsule had travelled to Bennu, a small asteroid in an orbit which crosses that of the Earth, as part of a mission called OSIRIS REx. In 2020 the mission’s main spacecraft briefly descended to Bennu’s surface and loaded the capsule with perhaps 140g of material. It then returned to the vicinity of the Earth, cast off the capsule and flew off to study another asteroid named Apophis. The capsule plunged into the atmosphere like an incoming meteorite; it failed to deploy its parachute in the way that had been planned (thus giving Dr Lauretta conniptions) but ended up safe and sound on the surface.

On December 11th Dr Lauretta provided the gathering with some preliminary results from his team’s analysis of its contents. Perhaps the most important was a negative one. The sample was pristine. Though bits of asteroids fall to the Earth every day as meteorites, they are not protected from the heat of re-entry or later contamination at the surface. The Bennu sample was.

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The electric grid is about to be transformed - The Economist   

In the turbine hall at Drax, a power plant in the English county of Yorkshire, sit six monsters of angular momentum. They are massive—2,800 tonnes each—and complex, composed of 28 turbine sub-assemblies. And they spin on their axes 3,000 times per minute. Place your hand on the blue metal casing around one of them and your whole body thrums in harmony. The hall’s floor hums a flattened A three octaves below middle C that numbs the soles of your feet.

The turbines are driven by high-pressure steam produced in vast boilers that hang from the ceiling. The boilers’ walls are meticulously insulated, but you can still feel the heat of their 1,100°C (2,000°F) bellies at 20 paces. For most of Drax’s life those flames have been fed by a steady stream of coal, tens of thousands of tonnes of it pulverised and blasted into the blaze every day.

Today, in a sign of the times, most of Drax’s boilers burn biomass instead. The shift is part of the move towards renewables taking place around the world. Removing fossil fuels from electricity generation is universally seen as a necessary, but not sufficient, step towards stabilising the level of greenhouse gases in the atmosphere. The attractions are clear: much of the world already runs on electricity; there are many sources of non-fossil-fuel energy available, some very cheap; and increasing electricity’s share of total energy use by encouraging use of electric vehicles, heat pumps and the like looks comparatively easy.

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