planet

01. I think there are 9 [planets] in our solar system, including the Earth.

02. Someday [planetary] space travel for tourists may become a reality.

03. Is there any intelligent life living on this [planet]?

04. We could see another [planet] through the telescope at the observatory.

05. Aldous Huxley once said that maybe this world is another [planet's] Hell.

06. Blue whales are the largest animals to have ever lived on our [planet].

07. If we don't do something to stop pollution, we may eventually kill most of the life forms living on our [planet] today.

08. Jupiter is so big that all the other [planets] could fit inside it.

09. Nikolai Copernicus, a Polish astronomer, was the first person to comprehend that [planets] move around the sun.

10. Jupiter's largest moon is bigger than Mercury, the smallest [planet].

11. Saturn has the greatest number of known moons of any [planet] in the solar system.

12. The [planet] Venus is named after the Roman goddess of love.

13. Jupiter is more than two and a half times larger than all the other [planets] combined.

14. In March of 1966, a Soviet spacecraft landed on Venus, the first spacecraft to land on another [planet].

15. The discovery of the [planet] Pluto was announced in March of 1930.

16. Scientists have discovered over 20 [planets] outside our solar system.

17. In geological terms, Mars represents an intermediate phase in [planetary] development which is transitional between a body like the moon and our own Earth.

18. The surface fluids on our [planet] are in constant motion.

19. Iris Murdoch once said that people from a [planet] without flowers would think we must be mad with joy the whole time to have such things about us.