HS-ESS1-6: Reconstructing Earth's Early History
Also called NGSS HS-ESS1-6 · Topic: History of Earth · Earth and Space Science
The Official Wording
Apply scientific reasoning and evidence from ancient Earth materials, meteorites, and other planetary surfaces to construct an account of Earth’s formation and early history.
Clarification statement: Emphasis is on using available evidence within the solar system to reconstruct the early history of Earth, which formed along with the rest of the solar system 4.6 billion years ago. Examples of evidence include the absolute ages of ancient materials (obtained by radiometric dating of meteorites, moon rocks, and Earth’s oldest minerals), the sizes and compositions of solar system objects, and the impact cratering record of planetary surfaces.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What HS-ESS1-6 Means in Plain English
Students piece together how Earth formed and what its first stretch of history was like. Because Earth's surface has been recycled, they turn to dated meteorites, moon rocks, tiny ancient crystals and the craters on other worlds as the clues.
No formal limit is set, but the aim is a reasoned story from evidence, not a memorized list of dates. It builds on radioactive decay (HS-PS1-8) and rock ages (HS-ESS1-5), and extends the geologic time scale from MS-ESS1-4.
HS-ESS1-6 I Can Statements
- I can explain why meteorites help date Earth's formation.
- I can use crater counts to compare the ages of surfaces.
- I can build a timeline of Earth's earliest history from evidence.
HS-ESS1-6 Worked Example
A timeline and crater-count lesson that reads Earth's missing early chapters from other objects.
If Earth's first surface is gone, how do we know when and how Earth formed?
Set It Up: A card of radiometric ages for meteorites, Apollo moon samples and Western Australian zircon crystals, a long paper strip, and a photo of the Moon's near side.
- Mark each dated sample on the paper strip as a timeline.Meteorites about 4.57 billion years, moon samples up to about 4.5, zircons about 4.4, oldest Earth rock about 4.0
- Notice which objects are oldest and explain why.Meteorites are leftover building blocks of the planets
- Draw two equal squares on the photo, one on the bright highlands and one on a dark mare, and count the craters in each.Highlands: dozens of craters, mare: only a few
- Decide which surface formed first and what that says about the early solar system.Highlands came first, heavily battered early on
- Write a short account linking the clues.Formed about 4.6 billion years ago, a solid surface by 4.4, heavy early impacts
The clues agree that Earth formed with the rest of the solar system about 4.6 billion years ago and went through an early period of heavy impacts.
Why it works: Meteorites and the Moon have changed little since they formed, so their ages and crater records preserve the early history that plate tectonics and erosion erased from Earth's own surface.
Common Mistakes with HS-ESS1-6
Expecting Earth's oldest rock to date the planet
“The oldest rock on Earth is 4 billion years old, so Earth is 4 billion years old.”
Try this: Earth's earliest crust was melted, recycled or worn away. Meteorites that formed alongside Earth give the older and better age, about 4.6 billion years.
Reading more craters as a younger surface
“The cratered highlands must be newer because they're rougher.”
Try this: Craters pile up over time, so a surface with more craters has been exposed longer. Smooth maria are younger lava that covered older craters.
Thinking Earth formed alone
A timeline that starts with Earth and adds the other planets much later
Try this: Earth, the other planets and meteorites all formed from the same disk around the young sun at nearly the same time.
Where HS-ESS1-6 Fits
Practice HS-ESS1-6
Quick Check
- Why do scientists date meteorites to find Earth's age?
- One region has 40 craters and another of equal size has 5. Which is older?
- How old is Earth, and what is the main evidence?