Earth Science: Geology, the Environment, and the Universe

Chapter 29: Our Solar System

Problem of the Week

Near Earth Objects

This topic has been the subject of several movies in the past several years. Though chances are small that we will experience a major impact, they do occur. The various groups that search for, discover, and track NEOs are working diligently to find the remaining NEAs that are estimated to exist.

*There is a great Power Point presentation at the first resource Web site. Check the menu for Presentations. In the presentation there is information on the importance of finding these NEOs, and the importance of advanced warning. The Web site also discusses options for destroying the threatening NEO. This would be good class discussion and project material.

Solution:

Step 1:	How many to discover by 2008?
	-There are an estimated 900 NEAs.
	-goal is to discover 90% by 2008.
	-90% of 900 = 0.90 × 900 = 810
	-430 NEAs have already been discovered
	-this leaves (810 – 430) = 380 to be discovered
Step 2:	How much time?
	-search time will include 2001 – 2008 = 8 years or (8 years ×12 month/year) = 96 months
	-if 5 NEAs are discovered per month, in 96 months (5 × 96) = 480 NEAs could be discovered.
	Conclusion: Yes, if the current average rate of discovery is maintained, they could accomplish their goal.

The logic is:
1. The average rate of discovery might decline, as there are fewer NEAs to discover.
2. If the project could continue more than 90% may be discovered.
3. Other reasonable answers should be considered.