21.   Astronomers suspect that these giant planets are, like Jupiter and Saturn, huge spheres of gas without a solid surface.

22.   Because these planets are so dark and give off relatively little energy, they cannot be seen with present technology, he said.

23.   Black suspects that the planet may be somewhat larger than the data indicate, and that it may be a sort of fizzled star rather than a true planet.

24.   A succession of major astronomical discoveries has revealed more and more that we inhabitants of Earth are not that special, that our planet may be one among many.

25.   A. The planets are round because of gravity, says Michael Mendillo, aprofessor of astronomy at Boston University.

26.   After a few years, Borucki said, astronomers should have a good estimate of just how common Earthlike planets might be.

27.   After all, there are planets hanging around it.

28.   Alarmed citizens of the Earth feared that God would not be able to find them if their planet were constantly moving.

29.   All five naked-eye planets will be readily visible in the same patch of sky, creating a striking assembly that will not be equaled again for decades.

30.   All the planets were in alignment.