Old Is Earth — How

Sea plants and first multicellular organisms emerge. 11:00 PM: Dinosaurs arrive. 11:40 PM: Dinosaurs go extinct. 11:58 PM: Modern humans (Homo sapiens) appear.

To make that massive number easier to visualize, imagine Earth’s entire history squeezed into a single : 12:00 AM: Earth forms. 4:00 AM: First simple, single-celled life appears. how old is earth

The Earth is approximately , with a margin of error of about 50 million years (roughly 1%). How we know Sea plants and first multicellular organisms emerge

Scientists arrived at this number primarily through of meteorite fragments and the oldest known rocks from the Earth and Moon. By measuring the decay of radioactive isotopes (like uranium turning into lead), geologists can calculate how much time has passed since the rock formed. The timeline in perspective how old is earth