Octopus embryo. This microscope image of a California two-spot octopus ( Octopus bimaculoides ) embryo was one of the top 20 images in Nikon’s Small World photomicrography contest. It was entered by biologists Martyna Lukoseviciute of the University of Oxford, UK, and Carrie Albertin at the Marine Biological Laboratory in Woods Hole, Massachusetts.

Junk food. A young jaguar ( Panthera onca ) in the Pantanal wetlands region in Brazil was spotted playing with a discarded plastic bottle by British wildlife photographer Paul Goldstein, who described the sight as ‘distressing’. He added that the animal was probably attracted by the scent of the bottle, which would have floated downstream during the wet season.

Friends reunited. Astronaut Christina Koch snapped this picture of the Soyuz spacecraft carrying her NASA colleague Jessica Meir as it approached the International Space Station (ISS). “What it looks like from @Space_Station when your best friend achieves her lifelong dream to go to space,” Koch captioned the picture on Twitter. On 18 October, the pair performed the first all-female spacewalk , to repair a faulty battery unit on the ISS.

Oil and water. Thirteen-year-old volunteer Everton Miguel dos Anjos works to remove a tiny fraction of the mysterious crude oil that has been washing up on Brazil’s coast for nearly two months. The sludge has contaminated thousands of kilometres of beaches in nine states in the northeast of the country. So far, more than 600 tonnes have been removed in clean-up efforts, but the source remains unknown.

Cosmic pretzel. The Atacama Large Millimeter/submillimeter Array (ALMA) telescope in northern Chile imaged these two young stars, each surrounded by a ring of dust and gases called a circumstellar disk. The stars are close enough together for their disks to intertwine, making a pretzel shape. These observations shed light on the earliest stages of star formation, and might help astronomers to understand the conditions under which binary stars — pairs of stars that orbit the same centre of mass — are formed.

Green plant. Amager Bakke, a waste-to-energy plant in Copenhagen, opened its 85-metre-tall sloping roof — which can be used as an artificial ski and hiking slope and climbing wall — to the public on 4 October. The facility has been generating both electricity and useful heat by burning municipal waste since 2017, and is claimed to be one of Europe’s most environmentally friendly plants. It is part of Copenhagen’s plans to reach net-zero carbon by 2025. The roof was designed by the architecture firm Bjarke Ingels Group.

Hills on fire. Flames rage on a hillside next to the 405 freeway in Los Angeles, California. The state has been ravaged by the largest wildfire on record this year, giving researchers opportunities to study the health effects of pollution linked to these events and to update the models first responders use to understand how fire spreads.

Cephalopod scavengers. Deep-sea octopus, eelpouts and bone-eating Osedax worms were spotted feeding on a whale’s carcass on the sea bed off the coast of California. Researchers at the Monterey Bay National Marine Sanctuary and the non-profit organization Ocean Exploration Trust captured the footage at a depth of more than 3,000 metres during the last dive of the organization’s 2019 Nautilus Expedition. The mission aimed to survey unexplored regions of the eastern Pacific with the research vessel Nautilus .