Spy on millions of sleeping butterflies and more — June’s best science images

Float like a butterfly. No, they’re not leaves. These trees in Michoacán, Mexico, are actually adorned with millions of sleeping Monarch butterflies (Danaus plexippus). The monarchs form dense clusters high up in the trees to rest and recover their strength after migrating around 3,000 miles from Canada and the United States during spring. This shot, captured by wildlife photographer Jaime Rojo, won the grand prize at this year’s Big Picture photography competition (see below for a selection of other winners). “Sights like this could potentially become rare in the future,” Rojo says in his competition entry. That’s “because of the realities of climate change, deforestation, and pesticide exposure, including an overall loss of the milkweed plant, the only plant in which the Monarchs lays their eggs.”

Image credits: Kazuaki Koseki, Shane Gross, Maddy Rifka, Jaime Rojo, Franco Banfi, Geo Cloete, Hema Palan/BigPicture Competition

Slippery shores. A collision between two ships in the Singapore Strait resulted in a spill of around 400 tonnes of fuel oil, much of which washed up on the city-state’s southern coastlines. Authorities immediately launched a clean-up operation to disperse patches of oil and remove contaminated sand, after the spill tainted several tourist beaches. Despite reports of marine animals covered in oil, conservation researchers are optimistic that clean-up efforts will help to mitigate any longer-lasting impacts on biodiversity in the region.

Moss piglet superpowers. Affectionately known as water bears or moss piglets, tardigrades are some of the hardiest creatures on the planet. They’re able to withstand freezing and boiling temperatures and can even survive the vacuum of space. Now, researchers are using CRISPR-Cas9 genome-editing technology to edit the genes of Ramazzottius varieornatus tardigrades. Here, a tardigrade is injected with CRISPR tools that will alter one of its genes, and those of the eggs that it produces. The researchers hope that a better understanding of the genetic traits of tardigrades will one day reveal what makes them so resilient.

Martian geysers. NASA’s Mars Reconnaissance Orbiter captured this image of ‘geyser season’ in Mars’s South Polar region. The period is characterized by eruptions of gas and dust through weaknesses in the layers of carbon dioxide ice that accumulate on the surface over winter. The gas forms when sunlight warms ice at the lower depths, causing carbon dioxide to sublimate and build up pressure. The fan shapes left by the geysers show the direction in which the wind was blowing at the time they erupted.

Salt-stain science. Chemists are developing a machine-learning algorithm that can identify the chemical composition of different salts based on the patterns they make when a droplet of the salt’s solution dries up. Researchers recorded 7,500 photos of 42 types of salt stain, and translated each image into parameters that can be rapidly analysed by the algorithm. These characteristics include pattern features such as texture, compactness and the arrangement of crystals. When tested on images that were not part of the initial data set, the program identified the correct salt 90% of the time. The team plans to improve on this by training the algorithm on thousands more images. Being able to visually identify chemicals in this way could have several applications, from blood testing to space exploration.

Stellar oddball. This bizarrely shaped object is a young star in the Orion Nebula, around 400 parsecs away from Earth. Its unusual appearance is the result of interactions with other stars that are out of shot. The bright yellow bow-shaped structure forms when radiation from stars beyond the upper-right corner of the image clashes with the material around the young star. The elongated purple ‘tail’ extending towards the bottom left is a disc of gas and dust — the kind of material that usually goes on to form planets. In this case, the disc is being dragged away from the star by stars outside the field of view. The image was taken by the Very Large Telescope in Chile. The different colours map the distribution of elements including hydrogen, nitrogen, sulfur and oxygen.