Mercury and Pluto - Universe Today
[/caption] Before Pluto was discovered, there were 8 planets in the Solar System; and Mercury was the smallest. And then in 1930, the discovery of Pluto brought that number up to 9. For most of the 20th century, scientists weren’t sure which was bigger, Pluto or Mercury. But accurate measurements helped scientists conclude that Pluto … Continue reading "Mercury and Pluto"