Weekly Online Lesson Online Lesson Archive Grade Level: 5-9 Subject: Science/Astronomy

Orbiting Eros

On February 14, 2000, at 11:00 a.m. Eastern time, the spacecraft NEAR (Near Earth Asteroid Rendezvous) achieved a notable 'first' when it entered orbit around asteroid 433 Eros. The date marks the beginning of a year-long study of the potato-shaped asteroid, during which time the spacecraft will inch closer and closer to the asteroid—maybe close enough to scratch the surface. The spacecraft has already sent a number of dramatic images of Eros.

This week the NEAR team will activate two more scientific instruments: the X-Ray/Gamma Ray Spectrometer and the Laser Rangefinder. Through the course of the mission, the laser scans will help determine Eros' exact shape, while the spectrometer will measure the asteroid's chemical elements.

Apart from the nine planets, our Solar System contains a multitude of minor planets, officially known as asteroids. Once known as the 'vermin of the skies,' scientists now recognize that these battered chunks of rock contain important clues to the events that took place during the formation of the Solar System. However, despite a handful of asteroid flybys involving spacecraft during the 1990's, many mysteries still remain.

This week's online lesson will help prepare you for a year of exciting NEAR news as you investigate asteroids.

NEO Program

Begin your investigation of near-earth objects at NASA's Near-Earth Object Program Web site. The NEO program was established in mid-1998 to "help coordinate, and provide a focal point for, the study of those comets and asteroids that can approach the Earth's orbit." Begin by reading the welcome, which explains that although one objective of NEO is to track asteroids that might collide with our world, NEO scientists are far more interested in finding out what asteroids might tell us about the formation of the solar system and, perhaps, the origins of life on Earth.

Where do asteroids come from and where are they? You'll find answers to a lot of basic questions about asteroids by clicking the Near Earth Objects link. Read the Introduction and Overview section, and then scroll down to learn about NEO groups, the number of known asteroids, and collisions with earth. Small particles come into contact with the atmosphere all the time (we see them as shooting stars), and occasionally meteorites make it to the surface.

In the Target Earth section you will read about a possible plan to gently nudge an asteroid out of harms way should the need ever arise. Why would it be better to nudge a large asteroid out of the way instead of blowing it to pieces?

If you still have questions after reading this page, try the FAQ link to see if you question is answered there. Also check out the Images link to see the latest asteroid images. End your visit to this site by reading recent NEO News and Updates, including the latest news about Eros and the NEAR project.

Project NEAR Mission Site

By learning more about the NEAR project now, you will have a great background when new developments, images, and discoveries are announced during the coming year. The place to go for information now and all year long is the Project Near Mission site. You will see links to news and recent images on the home page—and don't hesitate to explore these if you want—but to get to the heart of the site follow the links in the yellow navigation bar on the right.

Start with the Science and Engineering link to learn more about the science behind the mission. It's not all heavy-handed, either. Take a visual tour of the six specialized instruments (sensors) aboard NEAR and investigate what each one does. Learn about the NEAR spacecraft and see photos of pre-launch and launch. You can also take a pictorial voyage of NEAR's journey. And of course you can learn everything scientists are learning about 433 Eros. This section lets you explore right along with them.

Teachers should download the PDF NEAR Activity Book and browse other educational resources available at the site.

Asteroid Impact

The chance of a large asteroid or comet hitting the earth are slim, but we know it has happened in the past, and it may one day happen again. Learn more about Asteroid and Comet Impact Hazards at this NASA site. Read the Introduction and the fact sheet on Asteroids and Comets. Next, learn about the Torino Impact Hazard Scale for indicating the risk of a hazardous collision and investigate its origins. And you shouldn't miss the gallery of apocalyptic images.

While your mind is set on massive global destruction, visit this Computational Physics site to see a computer simulation of the impact of an asteroid off the New York Coast. Read the data and then watch the movie.

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