Earth's orbit is an ellipse, not a perfect circle. Earth's distance from the Sun varies by about 3 million miles throughout the year. Earth's orbit's semimajor axis is approximately 93 million miles.

Scientists are sharpening their forecasts for how long Earth can remain a comfortable home for complex organisms, and the latest work points to a much earlier cutoff than the classic textbook ...

Geophysicists have modeled how Earth’s magnetic field could form even when its core was fully liquid. By removing the effects of viscosity in their simulation, they revealed a self-sustaining dynamo ...