Cosmic calendar fact

Dinosaurs

Dinosaurs lived long before humans, but on the cosmic calendar they still arrive late in December.

Wonder question If dinosaurs are ancient, how can they still be late in the cosmic year?

On the cosmic calendar

When the universe's story is shown as one year, this event can be compared with everything else on the same scale.

Science time
around 230 million years ago
Calendar time
December 25th, 22:00:00
Date confidence
approximate date

What happened?

The earliest definitive dinosaur evidence comes from the Late Triassic Period, around 230 million years ago. Early dinosaurs were already recognisably dinosaurs, but they were not yet the giant animals many people picture first.

How do we know?

Scientists compare fossils, rock layers, and dates from rocks around fossil finds. The Natural History Museum source supports around 230 million years ago for the earliest definitive dinosaur evidence.

What is still changing?

Older fossils may be found, or known fossils may be understood in a new way. That could improve the article or evidence note before it visibly moves this top-level marker.

Why it matters

Dinosaurs feel unbelievably old, which makes them a useful doorway into deep time. On the cosmic calendar they appear late in December, showing that even famous ancient animals arrived after most of the universe's story had already happened.

Image credit: NASA/JPL-Caltech. Background source: Age-Defying Star.