Planets usually stay close to their host stars, tracing steady paths shaped by gravity. Yet some planets break free and drift alone through the Milky Way. Astronomers call these objects free-floating ...

In an unprecedented discovery, astronomers have detected a rare exoplanet located at the very edge of the Milky Way galaxy, using a method grounded in Albert Einstein’s theory of general relativity.

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers ...

Small but mighty, the red planet — our celestial neighbor — has made Earth’s climate what it is today. Mars’ gravitational pull serves as a stabilizing force for our home’s orbit, tilt and position ...