Age of Earth

Age of Earth

At 4.5 billion years old, it can be difficult to understand just how old Earth is, and the changes that have taken place on the planet in all that time. Looking at some of its life forms, how long they lived, and when they died helps provide some scale of Earth's long existence.


5 - 8


Earth Science, Geology

NGS Resource Carousel Loading Logo
Loading ...

Idea for Use in the Classroom

Earth has existed for 4.5 billion years. In that time, it has undergone amazing transformations as a variety of geologic processes have changed the planet.

Have students read the introduction to the infographic. Ask students, “Why does the author use the word ‘complex’ to describe the history of Earth?” Have students discuss events and concepts that have made Earth’s history complex. Next, ask students how scientists organize different time periods from Earth’s past. Have them look at the chart of different time periods in Earth’s history to find the answer.

Lead a class discussion asking students the following questions:

  1. How many years are tracked on this chart?
  2. What do you notice about the way this chart is organized? (You may have to help students realize the distinction between periods and eras.)
  3. Is the chart to scale? (If students think it is not, have them explain how they could reformat the chart.)
  4. What are significant events that occurred in Earth’s past that show up on the chart?
  5. What time period do you live in?
  6. How do you think scientists are able to determine the relative date of the fossils and rocks they find? (You may need to guide students to understand that the rock layers help scientists determine relative age. Younger rock layers, and material in it, form on top of older rock layers.)

In groups, you can have students compare and contrast different eras or time periods.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Tyson Brown, National Geographic Society
National Geographic Society
Production Managers
Gina Borgia, National Geographic Society
Jeanna Sullivan, National Geographic Society
Program Specialists
Sarah Appleton, National Geographic Society, National Geographic Society
Margot Willis, National Geographic Society
Clint Parks
Roza Kavak
Last Updated

October 19, 2023

For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.


If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.


Text on this page is printable and can be used according to our Terms of Service.


Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.