A Review of Asteroids — Fact or Fiction Demonstration

 

Science Guy with AsteroidOn 6 December 2008, Dr. Grant Stokes gave two identical presentations in the Lincoln Laboratory auditorium about asteroids and Lincoln Laboratory's role in searching for them. With a series of images, cartoons, and animation, Dr. Stokes explained to an audience of possible future astronomers and scientists what asteroids are, where they come from, where they're going, and whether they'll hit Earth with the same catastrophic force as they did in the movies "Deep Impact" and "Armageddon." He explained the Ceres Connection, Lincoln Laboratory's program for naming newly discovered asteroids in honor of science students who have won select science competitions and for their teachers or mentors.

Dr. Stokes told the audience that in the last ten years Lincoln Laboratory has discovered close to half of all known asteroids and over 2000 near-earth asteroids. Millions and millions of others, as yet undiscovered, are orbiting in the asteroid belt, which is where another planet should have been between Mars and Jupiter. He described the asteroid that crashed 65 million years ago and, scientists theorize, killed off the dinosaurs. A picture of the impact crater in the Yucatan peninsula demonstrated the size of the impact, and a timeline put into perspective how long ago it was, compared to human history and the evolution of a number of familiar animals.

Dr. Stokes showed images of other impact craters as a reminder that impacts do occur in our solar system, though we are less likely to meet the fate of the dinosaurs now that we can look for dangerous asteroids with the kind of sophisticated space-surveillance equipment used in the Lincoln Near-Earth Asteroid Research (LINEAR) program. The challenge is for LINEAR and other programs to find the asteroids before they find us. Dr. Stokes traced the history of asteroid hunting with time-lapse methods, from the early days of telescopes and drawings through photography to current charge-coupled devices, satellite tracking, and computer analysis.

"Deep Impact" and "Armageddon" may scare us with depictions of devastating collisions and tidal waves, and the real-life asteroids that have become media darlings may raise alarms. However, the most likely impacts are far smaller. The largest recent impact was in Siberia in 1908, when the Tunuska impact leveled a large forest. The Peekskill Meteor, a very recent event, was the subject of a series of home videos, shown by Dr. Stokes, as it blazed across the country in October 1992. The meteor actually did make impact, but this small asteroid broke down so much in its travels through the atmosphere that by the time it fell to Earth in the Hudson Valley, all it did was poke a hole through a car and generate a unique police report.

Dr. Stokes explained that the real solution is to look for a potentially dangerous asteroid a hundred years before it becomes a problem and then take action if needed. Even a small nudge will make a big difference in an asteroid’s orbit a long time in the future, as when NASA used a few hundred pounds of copper bullets to knock pieces off Comet Tempel 1. Although the experiment was more an effort to understand what comets are composed of, it slightly changed Tempel 1's orbit.

Dr. Stokes' show sparked many questions from his audience—what were the smallest and biggest asteroids to hit earth, does anything live on asteroids, what's the best theory about space aliens, do comets ever hit each other, and what about black holes? Dr. Stokes also invited his listeners to use clay asteroids to make impact craters in flour and cornmeal. At least one asteroid went home with one of the participants. Two other participants, Emmanuelle and Oliver, were inspired to make their own miniature tsunami. Will, a student at the Hellenic American Academy, brought a friend and an insatiable thirst for science and had a chance to hear science separated from science fiction. Students could also examine and hold meteors and fossils in a display outside the auditorium. Sarah, who had just done a project on the solar system in school, looked at a globe and saw a representation of the asteroid belt that explained her question about the big gap between Jupiter and Mars. "Asteroids: Fact and Fiction" not only provided her with new insight and information but also, as her mother said, introduced her to a scientific community in collaboration. Perhaps someday the Laboratory will discover a new asteroid that will be named for a student who attended Dr. Stokes's presentations at Science on Saturday.

 

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