If you were to imagine all of Earth's history as just one day, as in Carl Sagan's cosmic calendar, humans wouldn't arrive until the last few seconds before midnight. A few hundred thousand years of ...

When Earth first formed around 4.5 billion years ago, it was a ball of molten rock. Over time, heavier elements, like iron and nickel, sank to the planet's center, forming the Earth's early core.

The Earth's inner core was once liquid, but has turned solid over time. As the Earth gradually cools, the inner core expands outwards at the surrounding iron-rich liquid "freezes." That said, it is ...

Earth’s orbit around the Sun is not circular, but an ellipse that is slightly elongated with an eccentricity of 0.017. (An eccentricity of 0 is a circle, while the dwarf planet Pluto has a relatively ...

Earth’s rotation is slowing as melting ice moves across the planet. New research says it’s driven by climate change and is ...

SETI research often involves hunting for technosignatures—evidence of technology from distant civilizations. But how detectable is Earth to others with technology similar to our own? In a recent SETI ...

Nearly 5 billion years ago, a dense cloud of gas and dust occupied this corner of the Milky Way. The planets we know today, including Earth, were nowhere to be found. Scientists think that a nearby ...