Reference Terms
from Wikipedia, the free encyclopedia
Planet
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.
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Space & Time News
December 13, 2024
Dec. 13, 2024 — The galaxy M87, located in the Virgo constellation, provided the first-ever photo of a black hole in 2019, when the Event Horizon Telescope captured an image of the supermassive black hole at the ...
Dec. 12, 2024 — Stars similar to the Sun produce a gigantic outburst of radiation on average about once every hundred years per star. Such superflares release more energy than a trillion hydrogen bombs and make all previously recorded solar flares pale in ...
Dec. 11, 2024 — Stunning new photographs by a team of astronomers have revealed a newly forming galaxy that looks remarkably similar to a young Milky Way. The extraordinary images give us an unprecedented picture of what our own galaxy might have looked like when ...
Dec. 9, 2024 — New observations from the James Webb Space Telescope suggest that a new feature in the universe -- not a flaw in telescope measurements -- may be behind the decade-long mystery of why the universe is expanding faster today than it did in its infancy ...
Latest Headlines
updated 12:56 pm ET
Dec. 13, 2024 — A new study points to why, and how, Io became the most volcanic body in the solar ...
Dec. 13, 2024 — New radio astronomy observations of a planetary system in the process of forming show that once the first planets form close to the central star, these planets can help shepherd the material to form ...
Dec. 11, 2024 — The Sun generates its tremendous energy through the process of nuclear fusion. At the same time it releases a continuous stream of neutrinos -- ...
Dec. 9, 2024 — Photonic space-time crystals are materials that could increase the performance and efficiency of wireless communication or laser technologies. They feature a periodic arrangement of special materials ...
Dec. 10, 2024 — New research suggests that these ultra-high energy rays derive their energy from magnetic ...
Dec. 9, 2024 — A NASA Hubble Space Telescope observation program called OPAL (Outer Planet Atmospheres Legacy) obtains long-term baseline observations of Jupiter, Saturn, Uranus, and Neptune in order to understand ...
Dec. 9, 2024 — Dust storms on Mars could one day pose dangers to human astronauts, damaging equipment and burying solar panels. New research gets closer to ...
Dec. 9, 2024 — Could a decades-long debate about the mysterious movements of stars in Omega Centauri, the largest star cluster in the Milky Way, finally be ...
Dec. 9, 2024 — Astronomers have found a way to spot the smallest, 'decameter,' asteroids within the main asteroid belt. They used their approach to detect more than 100 new asteroids, ranging from the size of a bus ...
Dec. 5, 2024 — Colorful auroras appeared around Japan's Honshu and Hokkaido islands on May 11, 2024, sparked by an intense magnetic storm. Usually, auroras observed ...