Hello Nature readers, would you like to get this Briefing in your inbox free every day? Sign up here.

Black horny sponge among rocks covered in multicoloured organisms, and blue water.

A black horny sponge (Scalarispongia scalaris) growing off the coast of France. Some types of horny sponge are today harvested for bath sponges.Credit: Biosphoto/Alamy

Fossil could be from earliest known animal

Most major groups of animals first appear in the fossil record during the Cambrian explosion, 541 million years ago. But fossils resembling sponges found in northwestern Canada could be 350 million years older, significantly pushing back the date of Earth’s earliest-known animals. “If I’m right, animals emerged long, long before the first appearance of traditional animal fossils,” says geologist Elizabeth Turner, who found the fossils. Some scientists, however, are not convinced that the fossils’ branched, tubular patterns indicate an ancient sponge.

Nature | 5 min read

Reference: Nature paper

Water turned into shiny, golden metal

Researchers have transformed water into a metallic material by forming a thin layer of water around electron-sharing alkali metals. The water stayed in a metallic state for only a few seconds, but the experiment did not require the high pressures that are normally needed to turn non-metallic materials into electrically conductive metals. Co-author Pavel Jungwirth, a physical chemist, says that seeing the water take on a golden shine was a highlight of his career, and a reminder that science can be fun. “It’s not something you can get grant money for, but something you can do on your weekends.”

Nature | 4 min read

Reference: Nature paper

Predicting ‘breakthrough’ COVID cases

People fully vaccinated against COVID-19 are less likely to become infected with the coronavirus if they have relatively high levels of virus-blocking antibodies, according to a study of thousands of health-care workers who received the Pfizer–BioNTech jab. The analysis adds to a growing body of evidence that a person’s levels of ‘neutralizing’ antibodies, which block SARS-CoV-2 from infecting cells, predict whether that person will become infected. However, the analysis does not provide a specific level of antibodies that is associated with protection. Such a threshold “is what the field really needs to move forward”, says biostatistician Andrew Fiore-Gartland.

Nature | 4 min read

Astronomers detect light behind a black hole

Astronomers have detected light behind a supermassive black hole at the centre of a galaxy 245 million parsecs away. As well as spotting bright flares of X-rays bursting from the black hole, telescopes picked up unexpected ‘luminous echoes’, smaller and later X-ray flashes. “Any light that goes into that black hole doesn’t come out, so we shouldn’t be able to see anything that’s behind the black hole,” says astrophysicist Dan Wilkins. “The reason we can see that is because that black hole is warping space, bending light and twisting magnetic fields around itself.”

The Guardian | 3 min read

SKIPPER’S PICKS: NOTES FROM THE EDITOR-IN-CHIEF

As more and more people move to the cities, urban centres face a health crisis. Unfortunately, scientists are trying to tackle it by focusing excessively on biomedical solutions and neglecting environmental solutions, which could help to make urban centres healthier and more sustainable at the same time. To reverse this trend, we need to take an entirely new and much more collaborative and inclusive approach to urban development — especially in Africa and Asia, where cities are growing fastest. City planners, engineers, social scientists and public-health practitioners should seize this opportunity to come together, and should include policymakers and local communities.

Magdalena Skipper, Nature editor-in-chief

Project Syndicate | 7 min read (free registration required)

Features & opinion

Gardening writer chronicles climate change

From cabbage, snow peas and potatoes to tomatoes, pumpkins and okra, Jeff Lowenfels has created a long-term record of climate change in Alaska through his weekly gardening column that has been running since November 1976. His writings add to the increasingly important field of phenology — the study of climate-related biological rhythms, such as when flowers bloom or birds migrate — and could hint at what awaits for people rearranging plants across the world.

New York Times | 12 min read

Science’s diversity deficit extends to images

Last month, Nature published a Comment article on how researchers and communities helped each other during a water crisis in Flint, Michigan. While sourcing pictures for the article, Nature’s photo editor discovered that there are few images available of the people involved, many of whom are Black. A Nature editorial argues that a lack of diversity in science images creates a distorted and exclusionary picture of science’s past and present, and suggests ways that research institutions, as well as commercial photo agencies, can help to rectify the issue.

Nature | 5 min read

How to get media coverage

Science communicator Rebecca Fuoco offers advice on how to share your research with a wider audience. Among her top tips: release papers under embargo, write press releases that emphasise the newsworthiness of studies, collaborate with others and avoid misleading exaggerations.

Nature | 7 min read

Quote of the day

“To be a successful and sustainable researcher, you need to make sure you take care of yourself. Other people are going to push you, and it’s important to advocate for yourself and be realistic with what you can and cannot do.”

Physicist Jesse Heilman reflects on the importance of work-life balance.

In ‘How to be human in physics’, Heilman and three other physicists share their experiences dealing with major setbacks, trauma, mental-health issues and toxic work environments. (Symmetry | 11 min read)