Does our Solar System have 9 planets or only 8? Astronomers have gone back and forth on that a lot, with Pluto now being classified as a dwarf planet. However, out beyond Neptune there could be ...

The official number of planets outside our solar system has reached 6,000, according to space scientists. NASA's tally of ...

The spacecraft will map the boundaries of the heliosphere, study how Earth’s outer atmosphere reacts to solar activity and ...

The methane gas may constitute a rarefied atmosphere, or it may come from erupting plumes on Makemake’s surface.

Most planet-forming disks have warps that can lead to planets on inclined orbits, which could explain where the tilt of Earth's orbit came from. The origin of the differing tilts in the orbits of the ...

The known universe is full of shockingly huge things. Here are the largest planets, stars, galaxies, and structures we've ...

On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...

Who hasn't looked into the sky and wondered if there's life out there, somewhere, looking back at us? Is it possible there's alien life closer to home — within the bounds of our solar system? The ...

Credit: NASA During a total solar eclipse, the bright disk of the Sun is blocked, and the faint outer atmosphere becomes ...

Astronomers from the University of Arizona helped detect a baby planet outside of our solar system. Specialized telescopes from Arizona and Chile contributed to the discovery.