Hello Nature readers, would you like to get this Briefing in your inbox free every day? Sign up here.
The second-ever direct image of a black hole — Sagittarius A*, at the centre of the Milky Way.Credit: Event Horizon Telescope collaboration
First image of our Galaxy’s black-hole heart
Above is Sagittarius A* — the black hole at the centre of our Galaxy. It’s only the second time a black hole has been directly imaged. Like the first such image — of the supermassive black hole at the centre of a nearby galaxy called M87, in 2019 — astronomers created the picture by processing radio-wave observations that are invisible to the human eye. The long-awaited results were obtained from data collected in 2017 by the Event Horizon Telescope, a global network of radio observatories. Sagittarius A* seems to be rotating anticlockwise along an axis that roughly points along the line of sight to Earth. “What blows my mind is that we're seeing it face-on,” says astrophysicist Regina Caputo.
Go deeper with Nature’s feature from 2017 exploring exactly how the observation was made, which includes the prescient infographic below.
Reference: The Astrophysical Journal Letters papers
How life could have begun in an ‘RNA world’
Chemists say they have solved a crucial problem in a theory of life’s beginnings, by demonstrating that RNA molecules can link short chains of amino acids together. This might have allowed for ever-more complex RNAs, proteins and combinations of the two — a possible path to the chemistry of life that we know today. The findings support a variation on the ‘RNA world’ hypothesis, which proposes that, before DNA evolved, the chemical ancestors of biological life were based on RNA.
Young brain fluid boosts old mice’s memory
Cerebrospinal fluid (CSF) from 10-week-old mice can improve the memory function of older mice. CSF is a cocktail of nutrients that cushions the brain and spinal cord, but it loses its punch with age. Researchers found that old mice given an infusion of young CSF were more likely to remember being given small electric shocks than were old mice given artificial CSF. “This is super exciting from the perspective of basic science, but also looking towards therapeutic applications,” says neurobiologist Maria Lehtinen.
A worm by any other name
Parasitic worms are increasingly being named after scientists’ friends and family — and more often honour(?) male rather than female scientists. Researchers analysed nearly 3,000 species discovered in the past 20 years. The analysis uncovers ongoing biases in taxonomy and could be used as a jumping-off point for rethinking how scientists name species, says ecological parasitologist and co-author Robert Poulin. “When you name something, it is now named forever. I think it’s worth giving some thought to what names we choose.”
Features & opinion
Tests of NASA’s new Space Launch System rocket, seen here on its launch pad, revealed problems that have set back its first mission.Credit: NASA/Ben Smegelsky
How NASA plans to get back to the Moon
Artemis, NASA’s ambitious plan to return people to the surface of the Moon, will cost US$93-billion and require the world’s most powerful rocket, the Space Launch System. If all goes well, Artemis will give a major boost to science education and public awareness and open up an unexplored region: the lunar south pole. It will also showcase a notable change since the pioneering Apollo missions that first put footprints on lunar dust: NASA is relying on several privately developed lunar landers to achieve its exploration goals.
It all depends on water
Water flows across all aspects of climate-change mitigation and adaptation, argues Aditi Mukherji, who co-wrote the chapter on water in this year’s report from the Intergovernmental Panel on Climate Change. From droughts to floods, many people experience the impacts of climate change through its effects. Some well-intentioned plans to mitigate global warming — such as switching from fossil fuels to biofuels — can strain water resources. Climate solutions must keep water at the forefront — and heed people who are most vulnerable to water insecurity.
