Earth’s atmosphere has become less dusty over the last two decades, and scientists don’t know why. The mystery might, however, shed light on a different, unanswered question about climate change.

You might think the length of a day never varies—exactly 24 hours. You'd be wrong, at least if you count days in milliseconds, as physicists do. For about 30 years, scientists have known that the ...

Most kids learn in elementary school that the seasons are caused by Earth rotating on a tilted axis during its yearly orbit around the sun. The substantial tilt, about 23.5 degrees, is thought to be ...

A battle of forces, driven by the motion of Earth’s core, can explain small variations in the planet’s rotation, study finds. The planet’s rate of rotation changes subtly over time, giving rise to ...

Humans are continuing to push Earth beyond livable levels of heat, pollution and other conditions—both for us and for millions of species. That’s the upshot of the annual Planetary Health Check, ...