PRAGUE, Czech Republic — The universe really is expanding — astronomers are proposing to rewrite the textbooks to say that our solar system has 12 planets rather than the nine memorized by generations ...

Astronomers gazing upon a star system not too far from Earth were recently treated to a marvelous discovery: a group of six planets moving around a sun-like star in a seemingly perfect cosmic dance ...

The world’s astronomers, under the auspices of the International Astronomical Union (IAU), have concluded two years of work defining the difference between “planets” and the smaller “solar system ...

Our solar system is the sun and everything orbiting it, including planets. We have eight in our solar system, and you can see five without the aid of a telescope. Surrounding the planets in the sky ...

NASA has announced that astronomers working with the Kepler space telescope have verified 1,284 new planets — more than doubling the number of previously confirmed planets from Kepler. In fact, this ...

Scientists have discovered the closest multi-planet system around a red dwarf star to Earth. While these planets are unlikely to be habitable, they could be important worlds for future study. The rest ...