Astronomers have identified a quartet of small rocky planets orbiting Barnard's star - one of our closest stellar neighbors - ...

Here's what to know about the short life of what was, for a single human lifetime, the solar system's smallest planet. Pluto was discovered in 1930 by Clyde Tombaugh, an American astronomer at the ...

A spacecraft operated by the European Space Agency and the Japan Aerospace Exploration Agency has made its final flyby of Mercury, as scientists now work to guide BepiColombo into the planet’s ...

Caltech researchers have mathematical evidence suggesting a Neptune-sized Planet X may exist deep in the solar system in an orbit far beyond Pluto. Planet X could have a mass about 10 times that of ...

Located in Nagaizumi, Japan, this tiny park is the size of four pieces of paper—and it just set a Guinness World Record as the smallest in the world.