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Arch-shaped map of 4% of the northern half of the sky.

The lights in this sky map are supermassive black holes.LOFAR/LOL survey

Best-ever map of supermassive black holes

The image above might look like a sea of stars, but it actually shows the low-frequency radio signals from more than 25,000 supermassive black holes. The map covers 4% of the northern half of the sky and is the most detailed map yet of the objects. Researchers compared the view from Earth to looking out into the world while immersed in the water in a swimming pool. “We had to invent new methods to convert the radio signals into images of the sky,” says astronomer Francesco de Gasperin.

The Independent | 3 min read

Reference: arXiv preprint (accepted for publication in Astronomy & Astrophysics)

How Horizon Europe will shape research

Horizon Europe, the world’s largest multinational research and innovation programme, has issued its first call for grant applications. Over the next 7 years, the European Union’s giant research-spending scheme will distribute a record €95.5 billion (US$116 billion) — including €5.4 billion from a COVID-19 recovery fund — to basic-science projects and cross-border research collaborations that tens of thousands of researchers across 27 member states and more than a dozen other countries will carry out. It also heightens the focus on open science, equality, interdisciplinary research and practical applications.

Nature | 7 min read

First COVAX vaccines arrive in Ghana

COVAX, the global sharing mechanism for COVID-19 vaccines, has delivered its first doses. Ghana received 600,000 doses of the Oxford–AstraZeneca vaccine. “Today marks the historic moment for which we have been planning and working so hard,” Henrietta Fore, the executive director of the United Nations children’s charity UNICEF, said yesterday. “In the days ahead, frontline workers will begin to receive vaccines, and the next phase in the fight against this disease can begin.” COVAX aims to distribute two billion doses this year in the largest operation for vaccine procurement and supply in history.

The New York Times | 4 min read

Read more: How to move COVAX up from the back of the queue (Nature | 5 min read)

Zero

The number of flu cases detected so far this year in a survey of hundreds of thousands of swab samples in the United Kingdom. Scientists credit the achievement to record influenza vaccination levels and strategies to reduce COVID infections. (The Independent | 5 min read)

Features & opinion

Asymmetry in the heart of the proton

Physicists have glimpsed an imbalance in the types of antimatter that swim in the sea of quarks and gluons that make up the proton. A shoestring experiment 20 years in the making, called SeaQuest, has found that there are more down antiquarks than up antiquarks in the proton sea: on average, 1.4 down antiquarks for every up antiquark. The asymmetry could help to decide which of the competing theoretical models of the proton will come out on top.

Quanta | 9 min read

Go deeper in the Nature News & Views by physicist Haiyan Gao. (Nature | 7 min read)

Reference: Nature paper

Figure 1

Figure 1 | The internal structure of the proton and the Drell–Yan process. a, Protons consist of fundamental particles called quarks and gluons. The three ‘valence’ quarks come in two types (flavours), up (u) quarks and down (d) quarks; protons contain two u and one d. Each valence quark interacts with another through a gluon. Gluons can dissociate into quark–antiquark pairs (sea quarks), and can also interact with other gluons (normal quarks are shown here in red, antiquarks in blue). b, In the Drell–Yan process, a beam of protons is fired at target atoms. Any quark or antiquark in a beam proton annihilates when it encounters its opposite-sign counterpart in a proton in a target atom, thereby producing a virtual photon (a transient quantum fluctuation). In this example, a down valence quark in the beam proton encounters a down antiquark (—d) in a pair of sea quarks in the target proton; only the valence quarks in the protons, and one pair of sea quarks in the target proton, are shown, for simplicity. The virtual photon decays into a pair of particles, which can be a muon and an antimuon. Dove et al. analysed muon–antimuon pairs produced when protons are fired at liquid hydrogen and deuterium, and conclude that there are more anti-down quarks in protons than there are anti-up quarks — a finding for which no theoretical explanation has been agreed.

Podcast: The men who say no to ‘manels’

Bioinorganic chemist Paul Walton and physicist Sean Hendy became gender-equity allies after seeing how female colleagues were being treated differently at work. They noted that women were ignored or talked over in meetings and treated more harshly than male candidates in job interviews. They discuss the action they have taken, including observers for the recruitment process and a boycott of ‘manels’ — all-male panels.

Nature Working Scientist Podcast | 25 min listen

Clearing the air on reinfection

Reinfection with COVID-19 seems to be a rare, but ominous, prospect. The Atlantic explores the myriad factors at play when it comes to getting infected, again. “Infection is a two-player game, and a change in either contender can affect the dynamics of a second confrontation,” writes science journalist Katherine Wu. Reducing the virus’s opportunities to mutate will be key to maintaining our defences.

The Atlantic | 9 min read

DON’T MISS IT: THE WEEK’S MOST-READ STORIES

• Watch the spectacular video of the Perseverance rover’s jaw-dropping final descent, from the 21.5-metre-wide parachute billowing overhead to the final moments when the rover’s six corrugated wheels touched down on the red, rock-studded surface. (Nature | 4 min read)

• What is the best COVID vaccine? It’s not as simple as comparing reported effectiveness. Supplies, costs, the logistics of deployment, the durability of the protection they offer and their ability to fend off emerging viral variants all factor in for decision makers. And even measures of efficacy come with a degree of uncertainty. (Nature | 6 min read)

• A kangaroo painted in red ochre in a rock shelter in remote northwestern Australia is at least 17,100 years old — the oldest rock art yet dated on the continent. (New Scientist | 3 minute read)

• Preliminary analyses suggest that at least some COVID vaccines are likely to stop people from passing on SARS-CoV-2. But confirming that effect — and how strong it will be — is tricky because a drop in infections in a given region might be explained by other factors, such as lockdowns and behaviour changes. (Nature | 5 min read)

Quote of the day

“Artists and scientists alike are immersed in discovery and invention, and challenge and critique are core to both.”

Scientists and artists are working together as never before, finds a Nature poll. Both sides need to invest time, and embrace surprise and challenge, argues a Nature editorial.