See our four favorite scientific breakthroughs this month

What do whale earwax, popcorn, planets, and squirrels have in common? Science.

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

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

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

More from this series

How pigeons landed in cities, and more breakthroughs

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