Construct a scientific explanation based on evidence from rock strata for how the geologic time scale is used to organize Earth's 4.6-billion-year-old history.

More Stories in MS-ESS1-4

  1. Earth

    Oxygen-rich air emerged super early, new data show

    Scientists had thought animals were slow to emerge because they would have needed oxygen-rich air to breathe. A new study finds that plentiful oxygen may have developed early. So animals may have been late on the scene for another reason.

  2. Earth

    Cool Jobs: Mapping the unknown

    Scientists find different ways of exploring places humans will never visit — and drawing maps to help us better understand such mysterious places.

  3. Space

    Pollution may give ‘first’ stars a youthful look

    The oldest stars should be made of only light elements. But these suns may have sucked up heavier elements, giving them a more youthful appearance, a new study finds.

  4. Planets

    Asteroids boiled young Earth’s oceans

    At least two asteroids hit Earth 3.3 billion years ago. This superheated the atmosphere, boiled the oceans and shaped how early life evolved.

  5. Chemistry

    Cooking up life for the first time

    The basic components for life could have emerged together nearly 4 billion years ago on the surface of Earth, chemists report.

  6. Space

    Astronomers spy fastest speeding star

    A few stars have been spotted departing our galaxy. The fastest of these might have been propelled by another exploding star, a new study finds.

  7. Fossils

    Dino double whammy

    Most scientists think an asteroid helped kill off the dinosaurs. But new calculations suggest that asteroid might have gotten some help from a long series of volcanic eruptions in what is now India.