Pluto hogs the spotlight in the continuing scientific debate over what is and what is not a planet, but a less conspicuous argument rages on about the planetary status of massive objects outside our solar system. The dispute is not just about semantics, as it is closely related to how giant planets like Jupiter form.
Pioneering spacecraft from NASA and the Japanese space agency promise to reveal two unexplored asteroids later this year, officials said Wednesday, beginning surveys that will culminate in daring descents to capture samples for return to Earth, where eager scientists await a hands-on look at the specimens.
Two wayward space rocks, which separately crashed to Earth in 1998 after circulating in our solar system’s asteroid belt for billions of years, share something else in common: the ingredients for life. They are the first meteorites found to contain both liquid water and a mix of complex organic compounds such as hydrocarbons and amino acids.