There are thousands of Solar System objects classified as Potentially Hazardous Asteroids (PHAs), whose orbits bring them particularly close to Earth's orbit. Scientists estimate that there are thousands more PHAs yet to be discovered. Rubin Observatory is exceptionally good at discovering faint near-Earth asteroids because of its ability to frequently scan large areas of the sky and image very dim objects. In its first year of pre-survey operations, Rubin Observatory discovered more than 20,000 new Solar System objects, and by the end of its ten-year Legacy Survey of Space and Time (LSST), Rubin Observatory is predicted to discover about 5 million new objects, among them around 89,000 near-Earth asteroids.

Prerequisite Concepts

• Students should have been introduced to Newton’s laws of motion and gravity.

• Students should be familiar with magnitude scales.

• Optional: Students should be familiar with representing probability as a percentage or a fraction.

Learning Outcomes

• Students assess which near-Earth asteroids should be classified as potentially hazardous asteroids (PHAs).

• Students use models of orbits to determine the best location for follow up observations of newly-discovered asteroids

• Students explain how the orbits of asteroids can be altered by gravitational interactions with other Solar System objects.

• Students estimate the total number of PHAs to understand how rare Earth impacts are.

Essential Questions

• What is needed to accurately define the orbit of a newly-discovered Solar System object?
• What factors define a potentially hazardous asteroid?