Asteroid Exploration

by Terry Melo

Zooniverse has presented an intellectual challenge to citizen scientists called Asteroid Zoo. Asteroid Zoo shows them pictures taken from the Catalina Sky Survey and asks them to help identify and classify asteroids. Citizen scientists are everyday people whose degree or experience is not accounted for when they help science by offering another pair of eyes. This project is currently happening today and can be found on the Zooniverse website, but did it ever cross your mind when scientists decided to explore asteroids?

Let’s travel to the end of the 18th century when asteroids were first discovered. A group of scientists called themselves the “Celestial Police” and dedicated themselves to the search for the predicted planet between Mars and Jupiter. As the search continued, scientists and other astronomers instead discovered 4 ‘minor’ planets, which were actually asteroids.

The asteroid discovery marked the beginning of people researching asteroids and wondering what their impact will do to planets. For instance, telescopes were created to only find new asteroids, primarily ones potentially harmful to Earth. In 1980, Physicist Luis Alvarez and his team pinned the dinosaur extinction on the invasion of asteroids. In 1994, plenty of telescopes witnessed the impact of comet Shoemaker-Levy 9 on Jupiter. It left scars on Jupiter’s surface and on the minds of the people watching. Just about twenty years later, in February 2013, an asteroid about 19 meters in diameter exploded over Russia. We were unaware of the asteroid’s incoming, but its entrance was definitely noticed.

Based on the graph, the  next asteroid of about 19-20 meters is predicted to impact Earth in the next 100 years. The graph below depicts how often an asteroid of various sizes is planned to hit Earth. An asteroid’s impact on Earth becomes rarer as its size gets larger. An asteroid just about 4 meters in diameter is predicted to hit every year, while an asteroid greater than or equal to 2,000 meter in diameter is predicted to hit every million to 100 millions years. The last “global catastrophic” asteroid was the one that took out the dinosaurs! Other than the worry associated with their impact, asteroids are in high demand for the information they might expose. They contain minerals that can give us clues on what the solar system is made of. Hopefully with your participation in Asteroid Zoo and with the help of many telescopes worldwide, we can soon piece together the clues and state the origins of our very own solar system.



Time between asteroid impact (right axis) vs. asteroid size (the top axis). Credit:



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