Fluorescent fish and faraway galaxies — July’s best science images

Eye in the sky. The first scientific images from NASA’s James Webb Space Telescope have been released, offering unprecedented views of the distant Universe. The pictures capture thousands of faraway galaxies, nascent stars and the Southern Ring Nebula — a glowing shell of gas and dust that was ejected by a dying star. The images were broadcast to crowds worldwide, including on big screens in London’s Piccadilly Circus (pictured) and Times Square in New York City. Webb is the largest telescope ever launched into space, and astronomers expect it to revolutionize the study of the cosmos.

Luminous lumpfish. Scientists studying lumpfish (Cyclopterus lumpus) have discovered that young fish glow neon green under ultraviolet light owing to a phenomenon known as biofluorescence — in which an organism absorbs UV light and re-emits it at lower-energy wavelengths that we see as fluorescent colours. Biofluorescence has been observed in many marine species, as well as in mammals, such as wombats and spring hares. The researchers think that the bottom-dwelling lumpfish use their glow to communicate with each other in the depths of the ocean.

Sensory cells. These are sensory interneurons — a type of nerve cell in the spinal cord that helps to transmit sensations such as touch, pain, heat and itchiness. Using mouse stem cells, researchers have developed a detailed protocol for producing various types of sensory interneuron in the laboratory. If this work can be translated to human stem cells, it could be a step towards the development of stem-cell-based therapies that restore sensation for people with spinal-cord injuries.

Hiding in plain sight. Three new species of black-bellied salamander — Desmognathus gvnigeusgwotli (pictured), D. kanawha and D. mavrokoilius — have been described by scientists. Found in the Appalachian Mountains of the eastern United States, the salamanders come from different populations that have been studied for more than a century, but were all thought to belong to a single species. Genetic sequencing showed that the groups are evolutionarily distinct, and researchers say that there are also subtle but important differences in their sizes, shapes and colour patterns.

Fast learner. Researchers built this robot — nicknamed Morti — to investigate how animals learn to walk. Just like a newborn deer or a foal, Morti stumbles a lot during its first attempts, but the robot is equipped with sensors and a computer program that allows it to adapt the motion of its legs to minimize stumbling. The four-legged machine “features reflexes just like an animal and learns from mistakes”, says Felix Ruppert, who built Morti with Alexander Badri-Spröwitz at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany. It took just one hour for the robot to learn to walk.

Cold storage. A rat liver is loaded with cryo-protective chemicals as part of a research project that aims to find ways to extend the shelf-life of donated organs. At the moment, organs can be refrigerated, but not frozen, limiting the time that they can be kept outside the body to hours. By coaxing rat livers into a ‘partially frozen’ state, researchers found that the organs experienced limited ice damage and could still function after being cooled, stored at around −10 °C for up to five days and thawed.

Two faces. X-ray analysis of a painting by Vincent van Gogh has revealed a previously unknown self-portrait of the artist on the back of the canvas. Art conservators at the National Galleries of Scotland in Edinburgh discovered the ghostly image while examining Head of a Peasant Woman. The portrait itself is covered with glue and cardboard — probably applied ahead of an exhibition in the early twentieth century — but the lead-based pigments used in the paint can be distinguished easily on an X-ray. Van Gogh is known to have reused canvases to save money.