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Classroom Discussion Activity

Impact! Tracking Near-Earth Asteroids

Collisions between space objects are a vital part of the evolution of our Solar System. Most of Earth’s impact craters have been wiped away due to plate tectonics, but evidence of such cosmic catastrophes, such as Arizona’s 50,000-year-old Meteor Crater, do remain. When is Earth due for another major blast? Meet the professional and amateur astronomers who may be the first to know: first at LINEAR, a near-earth asteroid detection facility in New Mexico, and then at the Smithsonian’s Minor Planet Center, where orbits of near-earth objects are tracked for possible hits and misses.

Class Discussion

Establish prior Knowledge
Ask students to describe the asteroid belt — where is it, what is it composed of, and how it formed. Tell students that the video they are about to see is about
asteroids that may be headed towards Earth, and how they are being tracked.

Have students watch the video. Use the following questions to guide a class discussion.

  • Why are there so many craters on the Moon?
  • Why is it so difficult to find craters on Earth?
  • Why are scientists tracking the paths of asteroids? How?
  • What is the role of the network of observatories?
  • What are some of the possible outcomes of a large asteroid colliding with the Earth?
  • When is an asteroid considered close to Earth?
  • What is considered a high probability of an asteroid colliding with Earth?
  • How is it that the probability of asteroids crossing Earth’s orbital plane can change over time?


Ask students to brainstorm ways that scientists might try and stop an asteroid from colliding with Earth if one were identified to be heading our way.

Students who wish to explore more can visit these related links.

Near earth object program: frequently asked questions
An in-depth introduction to near-Earth objects, and their study.

Asteroid and comet impact hazards
Explore this site for an introduction to NEOs, FAQs, a multimedia gallery, and articles about the threat of impact hazards.

Find a meteorite: explore an asteroid
Learn details about the largest asteroids in our solar system, Eros, Gaspra, Vesta, and Ceres, through this site of NASA’s Dawn mission to the asteroid belt.

Science explorations: Journey into space
Gravity helps form the stars and planets and helps keep them in orbit. Yet, it can also cause these objects to collide. Explore the many ways gravity shapes—and reshapes—the universe.