Mercury is the smallest planet in our solar system. Explore its size, extreme temperatures, core structure, and comparison ...

WASHINGTON, May 30 (Reuters) - Scientists have identified an object about 435 miles (700 km) wide inhabiting the frigid outer reaches of our solar system that might qualify as a dwarf planet, spotting ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. An illustration of confirmed dwarf planets and their moons. From left to right: Pluto (with ...

WASHINGTON (Reuters) - Astronomers have identified a quartet of small rocky planets orbiting Barnard's star - one of our closest stellar neighbors - though they concluded that all of them are too hot ...