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1、Additional Materials Challenge Yourself Background Information12Index1. Dark MatterBackground InformationlLearning about dark matter helps determine the shape of the universe.lFritz Zwicky, a Swiss astrophysicist, was the pioneer in this field and the first to theorize dark matter in 1933, at the Ca
2、lifornia Institute of Technology. 1lZwicky observed that there was 400 times the mass in the Coma cluster of galaxies. Through further observation, he came to the conclusion that there must have been “invisible matter” or “dark matter” holding galaxies together. lIn 1950, a woman named Vera Rubin ma
3、de another startling discovery. Her conclusions contradicted Newtonian laws. She built on the theories of Zwicky to discover that galaxies showed an “extra motion.lOver the second half of the 20th Century many other important contributions to theories of dark matter have been made by the like of Mor
4、dehai Milgrom and Yakov Zeldovich. 2. Hubble Space Telescopela space telescope carried into orbit by the Space Shuttle Discovery in April 1990lnamed after the American astronomer Edwin Hubblelone of the largest and most versatile space telescopes, and well-known as both a vital research tool and a p
5、ublic relations boon for astronomy.lthe only telescope ever designed to be serviced in space by astronautslFour servicing missions: Servicing Mission 1 in December 1993 to correct Hubbles imaging flaw; Servicing missions 2, 3A, and 3B to repair various sub-systems and replace many of the observing i
6、nstruments with more modern and capable version3. Subaru Telescopelthe 8.2 meter flagship telescope of the National Astronomical Observatory of Japan, located at the Mauna Kea Observatory on Hawaiilnamed after the open star cluster known in English as the Pleiadeslthe largest telescope in the world
7、to use a single mirror as its primary mirror4. Gravitational LensinglLight is bent by clumps of matter along its path. Albert Einstein predicted this so-called gravitational lensing when he characterized gravity as the curvature of space-time. 5. American Astronomical Societyla US society of profess
8、ional astronomers and other interested individuals, headquartered in Washington, DClThe basic objective of the AAS: to promote the advancement of astronomy and closely related branches of sciencelIts secondary purposes: enhancing astronomy education and providing a political voice for its members th
9、rough lobbying and grassroots activitiesBACK1.What features do spacesuits have?2. Who made the first spacewalk?3. What tasks have astronauts performed on spacewalks?Challenge YourselfTips1. The features are pressurized with pure oxygen, and they have tough material with heating and cooling elements.2. The Soviet cosmonaut Alexey Leonov in 1965.3. They have been able to recover lost satellites. They have serviced orbit bodies, and have become the construction crew for the International Space Station.
