ASTR 220 Collisions in Space

Spring 2012 Course Introduction

The course "ASTR 220 - Collisions in Space: The Threat of Asteroid Impacts" will attempt to to answer the questions: What threat is there from space? What can we do to protect ourselves? Is it worth the cost? These questions have been prominent in the media, as the threat of asteroid impacts is hyped, and much fact and fiction is spread.

We will learn first about the origins of the solar system and asteroids, then we will focus specifically on near-Earth asteroids (NEAs), which are the ones that threaten the Earth. We will learn how astronomers observe asteroids in order to determine their key properties, such as size, mass, density, binarity, porosity, and rotation rate.

The next portion of the course will focus on the effects of impacts and the chances that an impact will occur. The effects of impacts of various sizes will be discussed, using historical impacts on the Earth, such as the Tunguska event and Meteor Crater, as evidence. The methods astronomers use to search for and discover NEAs will be demonstrated, as well as the uncertainties that remain in the characterization of any NEAs orbit. The orbit, as well as its uncertainties, is utilized by astronomers to determine the probability of an impact. Finally, the methods of communication astronomers use to convey these risks to the public will be discussed.

We will then focus on how an impact by an NEA could be prevented. The effects of the amount of warning time and the size of the impactor on a defense strategy will be taken into account. On-going missions to test defense strategies will be discussed.

In the final portion of the course, we will focus on the policy issues related to NEA searches and impact defense. The current budget for searches and defense will be presented. The risks of impacts and the effects of impacts, including costs, will be compared to the risks and effects of other disasters in order to provide context. We will discuss whether any search and defense effort should be funded and mounted entirely by the US, or whether the efforts should be international in scope.

This class is aimed at non-science majors. It will emphasize the scientific method and means scientists use to determine what we know about these astornomical phenomena. The only math skills required are those you should possess upon entry to the university: some simple algebra, the use of scientific notation, and how to interpret graphs.

The image in the background of this page is of the near-Earth asteroid Eros and was taken by the NEAR Project, NLR, JHUAPL, Goddard SVS, and NASA
The material on these webpages is Copyright © 2012 by Melissa N. Hayes-Gehrke and may not be reproduced without my permission.