Understanding the size of our galaxy depends on the definition used for our galaxy. There are a range of definitions, some very specific and some that delve into the realm of dark matter. The Milky ...

Is our Milky Way galaxy home to other planets the size of Earth? Are Earth-sized planets common or rare? NASA scientists seeking answers to those questions recently revealed their discovery. “We went ...

A new study presents a compelling new model for the formation of super-Earths and mini-Neptunes -- planets that are 1 to 4 times the size of Earth and among the most common in our galaxy. Using ...

One of the biggest recent surprises in astronomy is the discovery that most stars like the Sun harbor a planet between the ...