When astronomers began searching for extrasolar planets,they were surprised to discover Jupiter-sized planets much closer than 1 AU to their parent stars.Why is this surprising?
A) These planets must have formed at a larger radius where temperatures were cooler and then migrated inward.
B) Jupiter-sized, rocky planets were thought to be uncommon in other solar systems.
C) These planets must be the remnants of failed stars.
D) Earth-like planets must be rarer than Jupiter-sized planets in other solar systems.

Question

Quizplus · Accepted Answer

According to the prevailing theory of planet formation, large planets like Jupiter can only form far away from their parent star where temperatures are cool enough for gas and dust to clump together. Therefore, finding Jupiter-sized planets very close to their stars was surprising and suggests that they formed farther out and migrated inward.

When Astronomers Began Searching for Extrasolar Planets,they Were Surprised to Discover