See our four favorite scientific breakthroughs this month

The birth of worlds, in rings of stardust

The ALMA observatory in Chile, one of Earth’s most powerful telescope arrays, unveiled images in 2018 of the huge, dust-filled disks around 20 young star systems. Infant planets—big babies the size of Saturn or Neptune—may have carved gaps in the disks. —Michael Greshko

This is a whale’s earwax.

Museums have long collected whale specimens, many containing massive plugs of earwax (above: actual size, roughly 10 inches in length). Scientists have recently found that whales add two layers to a plug each year and that layers containing high cortisol levels correlate to times when whales face extra stress: during World War II, peak whale hunting, and the rise of ocean temperatures. —Christie Wilcox

Popping potential

Low-tech, low-cost robots could run on an unlikely material, say researchers at Cornell University: popcorn. When heat is applied, kernels undergo an “amazing transition,” expanding in less than a second, says engineer Kirstin Petersen. This makes popcorn a good candidate for powering a variety of robots, including those that must transform from flexible to rigid to perform a task. Imagine, for instance, a kernel-filled, silicone robot that can squeeze into a crack in a dam and then plug it by “popping.” Trials continue, but some popcorn robots already have a clear benefit: They’d be biodegradable. —Catherine Zuckerman

Flying squirrels also glow

In case the ability to glide between trees isn’t cool enough, under ultraviolet light, flying squirrels’ fur glows pink (above). They are one of the few mammals known to fluoresce: absorb light in one color, or wavelength, and emit it in another. The glow may aid nighttime perceptions and communication, especially in winter, suggests mammalogist Paula Spaeth Anich. “The trait might be more visible, or noticeable, in snowy conditions because of the high rate of UV reflectance off of snow.” —Jake Buehler

Read more about why North America’s three species of flying squirrels are all fluorescent.