Touchy subject

Human fingertips are exceptionally adept at detecting fine textural differences, with primates widely considered the gold standard for tactile sensitivity. But certain fish may have equally sensitive fins, according to a November study published in the Journal of Experimental Biology. Many fish navigate by touching surfaces with their fins, which inspired biologists Adam Hardy, SMʼ16, PhDʼ20, and Melina Hale, PhDʼ98, to investigate just how well these fish could feel. The researchers collected bottom-dwelling round goby fish and tested their sense of touch by measuring electric nerve signals while gently brushing their fins. To analyze how well the fish distinguished surface variations, the biologists rolled a wheel with ridges mimicking different textures against the gobiesʼ fins. The fishʼs nerve signal patterns matched the ridge patterns, suggesting the gobies can tell sand from stones. If fish fins are as sensitive as primate fingers, such tactile sensitivity may have evolved earlier than previously thought, long before fish and mammals diverged.

Star flare

Young stars are temperamental, shooting solar flares that can destroy nearby planet atmospheres—making them inhospitable to life as we know it. Understanding how often these flares erupt helps astronomers search for habitable exoplanets, which are unlikely to be found near flare-frequent stars. But to find evidence of flares, scientists must pore over thousands of light curves—graphs that track an objectʼs brightness over time—by eye. A study including astronomers Adina Feinstein, SMʼ19; Brian Nord; and Jacob Bean expedited the process by teaching a neural network (a brain-like computer system that mimics how humans process information) to search for the flares. The research, published in the November Astronomical Journal, applied the neural net to 3,200 young stars, discovering that stars with sun-like mass and temperature have fewer flares than cooler stars, and frequency seems to drop off after about 50 million years (the sun is 4.5 billion years old). Next the scientists want to adapt the neural network to search for planets around young stars to learn more about how planet atmospheres evolve.