In the past decades, the number of known exoplanets--planets in other solar systems--has skyrocketed. But we're still in the dark about a number of details, including how massive they are and what they're made up of.
In the past decades, the number of known exoplanets--planets in other solar systems--has skyrocketed. But we're still in the dark about a number of details, including how massive they are and what they're made up of.