Current Events Lesson Plan: October 13-19, 2016
Current Event: Rosetta and the Comet
On September 30, the space probe Rosetta crash-landed on the comet it had been orbiting, marking the end of an ambitious mission that paid–and should continue to pay–huge dividends for astronomy. The European Space Agency (ESA) launched Rosetta on March 2, 2004. Rosetta orbited comet 67P/Churyumov-Gerasimenko from August 2014 to September 2016. By gathering data on a comet, Rosetta helped scientists learn more about the solar system’s composition and history. Rosetta also carried a small craft named Philae to land on the surface of the comet’s nucleus (core). In 2014, when the lander Philae touched down on 67P, its landing harpoons failed to trigger. The craft bounced high into space and came down on its side in a sunless area of the comet’s nucleus. Scientists worked feverishly to conduct experiments and gather data for 57 hours before the lander’s solar-powered batteries died. Despite Philae’s loss, Rosetta continued orbiting the comet, taking photographs and collecting data. Rosetta was a fabulously successful mission. It became the first spacecraft to orbit a comet, and it released the first probe to land on (rather than crash into) a comet. It returned invaluable data about the evolution of comets as they approach the sun and the history of the early solar system.
Objective:
A comet is a bright heavenly body that often has a cloudy tail of light. A comet’s nucleus (center) is a ball of ice and rocky dust particles. As a comet nears the inner solar system, heat from the sun vaporizes some of the ice on the surface of the nucleus. The comet spews gas and dust particles into space. This gas and dust forms the comet’s coma. Radiation from the sun pushes dust particles away from the coma. These particles form a tail called the dust tail. Because comet tails are pushed by solar radiation and the solar wind, they always point away from the sun. Most of the comets that can be seen from Earth travel around the sun in long, oval orbits. We can see comets because the gas and dust in their comas and tails reflect sunlight. Also, the gases release energy absorbed from the sun, causing them to glow. The best-known comet is Halley’s Comet, which appears in the sky about every 76 years. The Behind the Headlines news story and related World Book articles explore comets and other astronomical topics.
Words to know:
Discussion Topics:
1. Some comets, including Halley’s Comet, orbit the sun. Ask your students if they know any other types of celestial bodies that orbit the sun. (They might say the eight planets; five recognized dwarf planets, including Pluto; occasional meteors; asteroids.)
2. Rosetta was named for the Rosetta stone, an inscribed rock that enabled scholars to interpret ancient Egyptian hieroglyphs. Ask your students if they can name other ancient civilizations. (They might say Assyrians, Babylonians, Celts, Chinese, Greeks, Israelites, Persians, Phoenicians, Romans.)
3. Private companies have begun launching people into space. Ask your students if they would want to visit another planet or any other celestial body. Assuming they could safely travel anywhere in space, where would they go? Would they go if they knew they could never return to Earth?
4. Ask your students to use World Book’s Timelines feature to view or add to the Advances in Space Exploration timeline. (Students may wish to use the World Book’s “Space exploration” article for help.)