|Saturn's largest moon is ____. It is larger than Mercury.
|The ____ comet can be seen about every 75 years.
|The ____ Space Telescope was launched in 1990.
|Nicolaus ____ proposed that the planets orbit the Sun.
|____ has just two small moons (Phobos and Deimos).
|Pluto's largest moon is ____. It was discovered in 1978.
|Clyde Tombaugh discovered ____ in 1930.
|____ is the hottest planet due to a runaway greenhouse effect.