11.   According to prevailing theory, a planetary system forms from a disk of gas, dust and chunks of rock that surrounds a newborn star.

12.   Albers compares the plutonium-prediction task to astronomers who predict the behavior of the planetary system.

13.   But no one can predict when the next close one will burst into view, seeding the universe with more ingredients for more planetary systems and possibly other life.

14.   Exotic propulsion schemes, like the use of antimatter as fuel, were proposed to drive vehicles across the vast distances between planetary systems.

15.   For several months, they had generally assumed the existence of extra-solar planetary systems.

16.   How could anyone observe the exquisite intricacies of this planetary system and conclude that it just happened?

17.   In recent decades, scientists had said the laws of probability favored the existence of other planetary systems.

18.   In the nascent field of comparative planetary systems, the new discovery has already given scientists a few insights.

19.   In the planetary system, the Sun is at one of the two focuses and an invisible point is at the other focus.

20.   It is only a matter of time, most astronomers think, before they will be able to compare and contrast the solar system with many other planetary systems.