Resonating oscillations of a planet’s atmosphere caused by gravitational tides and heating from its star could prevent a planet’s rotation from steadily slowing over time, according to new research by Caleb Scharf, who is the Director of Astrobiology at Columbia University. His findings suggest that the effect is enhanced for a planet with an atmosphere that has been oxygenated by life, and the resulting ‘atmospheric tides’ could even act as a biosignature.