2015 was a visual feast for science fans. Zombie beetles, sperm in a worm’s head, and close-ups of Pluto’s craggy surface are just a few of the sights that made us say “wow.” Here are 10 of our favorite images, all published online in Science news stories over the past year.
Helium rain on Saturn
When ultrapowerful lasers struck a diamond anvil, they instantly vaporized the diamond—but that was just a side effect of the experiment pictured above. The shock wave from the laser shot compressed a mixture of hydrogen and helium, mimicking conditions thought to exist deep within Saturn’s atmosphere. Researchers have long suspected that heat and pressure make the two elements separate like oil and water. The result: a helium “rain” that falls towards the planet’s core, releasing energy that causes Saturn to glow more brightly than otherwise expected.
Polar bears are losing to grizzlies in Alaskan food fights
SUSANNE MILLER/USFWS, MARINE MAMMALS MANAGEMENT
A grizzly bear and a polar bear seem to be getting along in the photo above, but that could change in an instant. Grizzly bears have been chasing polar bears away from whale carcasses like this one at Kaktovik, Alaska, despite the grizzlies’ smaller size. Researchers worry that the polar bears, which are already in trouble due to retreating Arctic ice, could suffer from lack of access to prime food sources.
Zombie beetle guards its own parasite
MATHIEU B. MORIN/ALAMY
This lady beetle is protecting its enemy. The cocoon between its legs holds a parasitoid wasp larva, which fed on the beetle’s insides before bursting from its belly. Now, researchers have discovered what makes the beetles act as babysitters: They are infected with a brain-controlling virus. When the larva emerges and spins its cocoon, the virus makes the beetle freeze in place, protecting the baby wasp from predators.
World’s oldest sponge
Scientists have identified a fossil just a millimeter long as the earliest known sponge, helping resolve debates about when the sponge lineage diverged from that of more familiar animals. The little sponge pictured above lived 600 million years ago, tens of millions of years before some researchers thought sponges first appeared.
Philippine reef carpeted in new sea slug species
© CALIFORNIA ACADEMY OF SCIENCES
In one patch of reef in the Philippines, researchers found more than 40 different kinds of sea slugs that are likely new to science, including the lacy-looking specimen above. During the larger expedition, divers explored both shallow and deep sites in the Verde Island passage, a little-known hotspot of marine diversity. They found more than 100 probable new species, from barnacles to heart-shaped sea urchins.
How corals use colors as sunscreen
JÖRG WIEDENMANN AND CECILIA D’ANGELO
Corals like those shown above rely on symbiotic algae to get energy from the sun. But too much sun can kill the algae, so corals produce pigments as a kind of sunscreen, growing brighter when the sun is harsh and paler when the rays are less intense. Now, researchers have discovered how the corals’ pigment genes control the range of colors they can produce. The more copies of the pigment gene a coral has, the brighter its range of potential colors.
Pluto’s ice mountains float on solid nitrogen
Last July, NASA’s New Horizons spacecraft swooped near Pluto, snapping the first close-ups ever taken of the dwarf planet’s surface. This photo has a resolution of about 80 meters per pixel, crisp enough to show the jagged edges of ice mountains that rise above a plain of frozen nitrogen. The rubble along the shoreline indicates that the ice mountains have drifted, moving across the more malleable nitrogen surface.
Insulin patch could spare diabetics from painful injections
These spikes may look fearsome, but they are shorter than the thickness of a credit card, causing no more pain than a mosquito bite when applied to the skin, according to researchers. Once there, the needles deliver insulin in response to changes in blood sugar levels. Some day, such needles—which are attached to a patch the size of a penny—may spare diabetic patients from having to inject themselves with insulin.
Squid squirts bacteria to protect its eggs
In the reproductive tract of the Hawaiian bobtail squid, there is a mysterious gland that has puzzled researchers for almost a century. Now, researchers have found out what it’s for: The gland releases bacteria that protect the squid’s eggs from fungus. When researchers applied antibiotics to freshly-laid squid eggs, fuzzy fungus soon moved in, smothering the eggs of the gemlike creatures.
A dinosaur called “strange wing”
DINOSTAR CO. LTD.
A pigeon-sized dinosaur recently discovered in China was related to early birds, but had wings totally unlike its feathered kin. It had long rods extending from its wrists, which apparently supported membranous wings like those of a bat, as seen in this artist’s conception. No other known dinosaur had such rods, prompting researchers to name the creature Yi qi—“strange wing” in Mandarin Chinese.
*Correction, 23 December, 5:08 p.m.: An item about flatworms has been replaced due to a issue with the image.