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91av’s guide to the 21 best ideas of the 21st century

Humans

91av’s guide to the 21 best ideas of the 21st century

A quarter of a century in, this is our definitive pick of the ideas in science and technology that are already transforming the world

Features

tardigrades

Life

Giving astronauts tardigrade toughness will be harder than we hoped

News

little red dots

Space

Distant 'little red dot' galaxies may contain baby black holes

News

The four crew members of NASA's SpaceX Crew-11 mission

Space

NASA is performing an unprecedented medical evacuation from the ISS

News

Project Hail Mary

Comment

The science-fiction films to look forward to in 2026

Culture

This new NASA/ESA/CSA James Webb Space Telescope Picture of the Month features a rare cosmic phenomenon called an Einstein ring. What at first appears to be a single, strangely shaped galaxy is actually two galaxies that are separated by a large distance. The closer foreground galaxy sits at the center of the image, while the more distant background galaxy appears to be wrapped around the closer galaxy, forming a ring.?? Einstein rings occur when light from a very distant object is bent (or ???lensed???) about a massive intermediate (or ???lensing???) object. This is possible because spacetime, the fabric of the Universe itself, is bent by mass, and therefore light travelling through space and time is bent as well. This effect is much too subtle to be observed on a local level, but it sometimes becomes clearly observable when dealing with curvatures of light on enormous, astronomical scales, such as when the light from one galaxy is bent around another galaxy or galaxy cluster. When the lensed object and the lensing object line up just so, the result is the distinctive Einstein ring shape, which appears as a full circle (as seen here) or a partial circle of light around the lensing object, depending on the precision of the alignment. Objects like these are the ideal laboratory in which to research galaxies too faint and distant to otherwise see. The lensing galaxy at the center of this Einstein ring is an elliptical galaxy, as can be seen from the galaxy???s bright core and smooth, featureless body. This galaxy belongs to a galaxy cluster named SMACSJ0028.2-7537. The lensed galaxy wrapped around the elliptical galaxy is a spiral galaxy. Even though its image has been warped as its light travelled around the galaxy in its path, individual star clusters and gas structures are clearly visible. The Webb data used in this image were taken as part of the Strong Lensing and Cluster Evolution (SLICE) survey (programme 5594), which is led by Guillaume Mahler at University of

Space

I'm calling it – 2026 is going to be the year of the galaxy

Comment

Space

The first commercial space stations will start orbiting Earth in 2026

News

Image of night sky

Space

Star that seemed to vanish more than 130 years ago is found again

News

Space

BepiColombo mission will start to unpick Mercury's secrets in 2026

News

Space

NASA's Artemis II mission aims to return astronauts to moon in 2026

NASA’s Artemis II mission will send four astronauts on a loop around the moon in preparation for putting humans back on the lunar surface for the first time since 1972

News

Space

The century-long hunt for the gigantic meteorite that vanished

Features

Space

The best space pictures of 2025, from supernovae to moon landings

News

Space

The essential guide to proving we’ve found alien life

Features

Space

Comets were on fire this year – for better or worse

Comment