Since astronomers first measured the size of an extrasolar planet 17 years ago, they have struggled to answer the question: how did the largest planets get to be so large?

Since astronomers first measured the size of an extrasolar planet 17 years ago, they have struggled to answer the question: how did the largest planets get to be so large?
The Atacama Large Millimeter/submillimeter Array (ALMA) has got a closer look at the most luminous structure in the cosmos
Learn the violent and turbulent history of our largest natural satellite in this video.