New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia


The International Astronomical Union defines "planet" as a celestial body that, within the Solar System that is in orbit around the Sun; has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape; and has cleared the neighbourhood around its orbit; or within another system, it is in orbit around a star or stellar remnants; has a mass below the limiting mass for thermonuclear fusion of deuterium; and is above the minimum mass/size requirement for planetary status in the Solar System.

Note:   The above text is excerpted from the Wikipedia article "Planet", which has been released under the GNU Free Documentation License.
Related Stories

Space & Time News
November 27, 2023

In 1991, an experiment detected the highest-energy cosmic ray ever observed. Later dubbed the Oh-My-God particle, the cosmic ray’s energy shocked astrophysicists. Nothing in our galaxy had the power to produce it, and the particle had more energy ...
If you look at massive galaxies teeming with stars, you might be forgiven in thinking they are star factories, churning out brilliant balls of gas. But actually, less evolved dwarf galaxies have bigger regions of star factories, with higher rates of ...
The latest image from NASA's James Webb Space Telescope shows a portion of the dense center of our galaxy in unprecedented detail, including never-before-seen features astronomers have yet to explain. The star-forming region, named Sagittarius C ...
Astronomers have used recent observations made with the James Webb Space Telescope to study the atmosphere of the nearby exoplanet WASP-107b. Peering deep into the fluffy atmosphere of WASP-107b they ...
Latest Headlines
updated 12:56 pm ET