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 ...

A new study suggests Earth formed almost entirely from material in the inner Solar System, challenging the idea that water-rich material from beyond Jupiter played a major role. If correct, Earth’s ...

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 ...

For practical purposes, we say that one day—the time it takes for Earth to rotate once on its axis—equates to 24 hours. In reality, different factors across different timescales influence how quickly ...

Equal Earth projection, adopted by the UN last week, provides an alternative to 16th-century Mercator display Three cartographers have spoken of their astonishment at the UN’s near-universal adoption ...

From Obama’s chef to a big cat obsessive, the actor has gathered experts from all over the world for a film about how to heal our besieged planet. He talks about naysayers, elephant tusks – and the ...

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, ...