Curiosity Creates Teaching Opportunities

by Edna DeVore - Deputy CEO

Nov. 07, 2000 "Are we alone?"It's a question asked by curious kids of all ages including grown-up kids called scientists. In the classroom, the question may take different forms: Do extraterrestrials exist? Can we look for and find ET? Are aliens visiting Earth? Did ETs land in Roswell, New Mexico, or are ETs hidden in the Nevada desert? Can NASA send a spaceship to search the galaxy for ET?In this activity, students consider how long it takes to travel to Sirius using different modes of transportation: walking, bicycling, driving, flying, and traveling in the space shuttle or a spacecraft. . The lesson is part of the SETI Institute's award winning "Life in the Universe" curriculum series for grades 3-9.Although some may consider these questions distractions in these days of standards and accountability, questions driven by kids curiosity are springboards to learning. They create teachable moments because they tap students interests and can be the motive for good science teaching and learning.So, can NASA send a spaceship around the galaxy to look for ET? A charmingly wonderful ideajust imagine being able to direct your own spaceship anywhere in the Milky Way Galaxy, by employing the well-known command, "Make it so!" It works in Hollywood, why not in real life?Thats the teachable moment. Its the opportunity for students to explore the dimensions of the galaxy and learn about the vast distances between the stars. A scale model of the solar system --our local star and its retinue of planets -- begins the journey. If the Sun and solar system is scaled at one-one hundred-thousandth its true size, the Sun can be represented by a volleyball 8 inches (about 20 centimeters) in diameter and the planets as pinheads and marbles.On this scale, the small rocky planets fit into your local football field: Mercury, a sand grain, sits on the 10-yard (meter) line and Venus is at the 19. Pinhead-sized Earth lies at the 26-yard line and a smaller pinhead -- Mars -- is farther out at the 39-yard line. Marble-sized Jupiter orbits 133 yards away, well beyond the end zone, and distant sand grain-sized Pluto is 1,000 yards, 10 football fields, away. On this scale, the nearest star, Proxima Centauri, is roughly 4,000 miles (6,437 kilometers) away.And the brightest nighttime star, Sirius, is even farther out at around 8,500 miles (13,680 kilometers). And they are just our next-door neighbors. On this scale, our Milky Way Galaxy stretches from Earth to the Sun. But the vast distances to even the nearest stars do not seem overwhelming to most kids. After all, if the Hollywood heroes of science fiction can "make it so," why cant we?The problem is travel time. Anyone familiar with urban traffic knows that city folk talk about how long it takes, rather than how many miles it is to their destination because their travel speed is limited. Its the same when we consider traveling to the stars. Back at the football field, our current spacecraft take a minimum of six months to reach Mars just 13 yards away from Earth in the model. At the same rate of speed, it would take several decades to reach Pluto and hundreds of thousands of years to reach the nearest stars.We simply do not have the technology travel to the nearest star in a human lifetime, let alone around the galaxy to look for ET one planet at a time. Will this change? Yes and no, humans are learning how to travel faster and farther, but like all beings in the universe, we do face a speed limit -- the speed of light.Light is the fastest thing in the universe -- but its maximum speed is 186,000 miles (299,330 kilometers) per second. So, it takes light 4.2 years to travel from Proxima Centauri to Earth, 8.6 years from Sirius and 100,000 years to cross the galaxy. And today, our spacecraft are only capable of less than 1 percent the speed of light.Because of these limitations, we learn about the larger universe remotely through observing with all kinds of telescopes, including the radio telescopes that listen for signals that will pinpoint the distant home planet of ET.