Mya facts for kids

Mya is a short way to say "million years ago." Scientists use this term a lot when they talk about things that happened a very, very long time ago. It helps everyone understand just how old something is, like a dinosaur fossil or an ancient rock.

What Does Mya Mean?

When you see "Mya" in a science book or documentary, it means a specific number of millions of years have passed since an event. For example, if something happened 65 Mya, it means it took place 65 million years ago. This is a huge amount of time, much longer than human history.

Why Do Scientists Use Mya?

Scientists use "Mya" because it's a simple and clear way to talk about Earth's long history. Our planet is about 4,540 Mya old! That's 4.54 billion years. Using "Mya" makes it easier to compare different events across these vast timescales. It helps them organize and explain the timeline of life and geology.

Mya in Earth's History

Many important events in Earth's past are measured in Mya. For instance, the last dinosaurs lived around 66 Mya. The first simple life forms appeared much earlier, perhaps over 3,500 Mya. Understanding these dates helps us piece together how life and the planet have changed over time.

Mya and Fossils

Fossils are the preserved remains or traces of ancient life. When scientists find a fossil, they try to figure out its age. They might say a fossil is from 200 Mya, meaning the creature lived 200 million years ago. This helps them understand when different plants and animals lived and how they evolved.

How Do We Know the Age of Things?

You might wonder how scientists can know something happened millions of years ago. They use special methods to date rocks and fossils.

Dating Rocks and Fossils

One main way is called "radiometric dating." This method looks at tiny amounts of radioactive elements inside rocks. These elements decay, or break down, at a very steady rate. By measuring how much of the original element is left, scientists can calculate how old the rock is. Since fossils are often found in layers of rock, dating the rock helps them figure out the fossil's age too. This is how we know the age of Earth, dinosaurs, and many other ancient things.