Five planets are visible to the naked eye. With the aid of the telescope, Uranus was added to the list in the 18th century, and in the 19th century, Neptune. Astronomers predicted an even more distant planet would be found. In 1930, this ninth planet was discovered and named Pluto. Recently, some astronomers have questioned whether Pluto is a true “planet” or not. It is even smaller than seven of the moons circling other planet, including Earth’s moon. Its orbit is so strange that for a 20-year period during its long 248-year revolution around the sun, Pluto is actually closer to the sun than is Neptune, a feat no other planet comes even close to. Despite these anomalies, most members of the astronomical society still consider Pluto the ninth planet.
【題組】45.
Which of the following statements is true concerning the size of Pluto? (A) It is larger than the Earth’s moon. (B)It is the largest moon in the solar system. (C) It is the smallest planet in the solar system. (D) It is the smallest moon in the solar system.
寫作批改
VIP與詳解卡管理
私人筆記( 0 )