Hello Nature readers,
Today we learn that there might be a link between weak democratic institutions and faster ageing, explore how smart brain-zapping implants could revolutionize Parkinson’s treatment and discover a gut microbe that makes cancer therapy more effective in mice.

Collision of ‘forbidden’ black holes

The biggest ever merger of colliding black holes involved holes that were too massive to have formed from collapsing stars. And the holes were spinning about 40 times per second — near the limit of what Einstein’s general theory of relativity allows. These ‘forbidden’ high-mass black holes might have been the product of an earlier merger. It’s like “four grandparents merging into two parents merging into one baby black hole”, says physicist Alan Weinstein. The discovery was enabled by two US-based detectors at a time when funding for gravitational-wave detection faces devastating cuts by the administration of US President Donald Trump.

Gut microbe can turbocharge cancer drug

A bacterium in the gut microbiome can supercharge the effects of cancer drugs, called immune checkpoint inhibitors, in mice. The microbe, Hominenteromicrobium mulieris, stimulates immune cells that go on to amplify the effects of checkpoint inhibitors, which unleash the mice’s own defences against tumours. Checkpoint inhibitors can be potent cancer-killers, but don’t work for everyone who receives them. Researchers are now planning a clinical trial to test whether H. mulieris has a drug-boosting effect in people.

How politics might accelerate ageing

Sociopolitical factors, such as social inequality and weak democratic institutions, are associated with faster ageing — which could help to explain why rates of ageing vary from country to country. A study of more than 160,000 people across 40 countries found that environmental factors such as high levels of air pollution can also accelerate ageing, as can less-surprising factors such as high blood pressure. How physical ageing is linked to a person’s socio-economic and political environment is unclear, but the mechanism might be stress’s physical effects on the body and brain, says neuroscientist and study author Agustín Ibañez.

Fossil-finder gets nod for NAS presidency

Palaeontologist Neil Shubin has been nominated to take over the presidency of the US National Academy of Sciences (NAS) next year. If the decision is confirmed, Shubin will also replace current president Marcia McNutt as chair of the National Research Council, the publications and operating arm of the NAS, which has had dozens of contracts cancelled by the Trump administration. Shubin, who regularly posts on social media about the value of basic science, says that although the NAS is non-partisan, “it’s not political to state the fact that investments in science enhance our well being, expand our knowledge of the world, and drive economic growth”.

Brain implants zap Parkinson’s symptoms

Hundreds of thousands of people have implants that deliver electrical pulses to a region of the brain associated with movement, to regulate the aberrant signals associated with Parkinson’s disease. A next-generation feature — already present in many implants but not yet turned on — precisely tailors the rhythm of the output to the brain waves of the user. This technology, known as adaptive deep-brain stimulation (aDBS), showed enough promise in trials that it was approved earlier this year in the United States and Europe. aDBS seems to head off some unwanted effects of deep-brain stimulation and shows promise for treating other disorders, such as Tourette’s syndrome and depression. But funding for expensive trials, which have mostly taken place in the United States, has fallen foul of federal budget cuts.

What I saw when I looked into deep time

For more than 90% of our planet’s history, it was without oxygen — and thus without flames. That’s one of that revelations that have stuck with science writer Laura Poppick after writing her new book, Strata. Another was the “solace and grounding” offered by looking into the deep well of Earth’s history. “Immersing myself in deep time and seeing the world through a geologic lens has transformed the way I experience even my most mundane daily activities,” says Poppick.

Podcast: the life of a wildlife filmmaker

In the latest episode, the podcast Nature hits the books swaps the written word for a glimpse behind the scenes of nature-documentary making. Wildlife film-maker and camera operator Vianet Djenguet tells host Benjamin Thompson about his career and his experiences working with local researchers to capture footage of endangered animals on the new Apple TV+ series The Wild Ones. The show is “is a cocktail of adventure. You have conservation, you have fun. It balances everything”, says Djenguet. “It was an honour teaming up with those scientists.”