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
May 15, 2024
May 15, 2024 — Astronomers have just discovered a new Earth-sized exoplanet around SPECULOOS-3, an 'ultracool dwarf' star as small as Jupiter, twice as cold as our Sun, and located 55 light-years from Earth. After ...
May 14, 2024 — Astronomers discovered three of the oldest stars in the universe, and they live in our own galactic neighborhood. The stars are in the Milky Way's 'halo' -- the cloud of stars that envelopes the ...
May 8, 2024 — Researchers may have detected atmospheric gases surrounding 55 Cancri e, a hot rocky exoplanet 41 light-years from Earth. This is the best evidence to date for the existence of any rocky planet atmosphere outside our solar ...
May 6, 2024 — Billions of years ago, Venus may have harbored as much water as Earth. Today, almost all of it has disappeared. A new study may help to explain ...
Latest Headlines
updated 12:56 pm ET
May 14, 2024 — Astronomers have just discovered WASP-193b, an extraordinarily low-density giant planet orbiting a distant Sun-like ...
May 8, 2024 — In the quest for life beyond our solar system, a new study delves into the atmospheric dynamics of planet Proxima Centauri b, illuminating ozone's pivotal role in shaping planetary climates. This ...
May 10, 2024 — Astronomers have proposed a new theory to explain the origin of phosphorus, one of the elements important for life on Earth. The theory suggests a type of stellar explosion known as ONe novae as a ...
May 9, 2024 — Astrophysicists discovered that an exoplanet is covered with so many active volcanoes that seen from a distance it would take on a fiery, glowing-red ...
May 9, 2024 — A recent study has discovered a novel method for detecting the first-generations stars, known as Population III (Pop III) stars, which have never been directly detected. These potential discoveries ...
May 8, 2024 — After starting science operations in February, Japan-led XRISM (X-ray Imaging and Spectroscopy Mission) studied the monster black hole at the center of galaxy NGC ...
May 6, 2024 — Astronomers observed the elusive starlight surrounding some of the earliest quasars in the universe. The findings may shed light on how the earliest supermassive black holes became so massive despite ...
May 6, 2024 — Bright, starry spiral arms surround an active galactic center in a new NASA Hubble Space Telescope image of the galaxy NGC 4951. Located in the Virgo constellation, NGC 4951 is located roughly 50 ...
May 6, 2024 — New discoveries about Jupiter could lead to a better understanding of Earth's own space environment and influence a long-running scientific debate about the solar system's largest ...
Apr. 29, 2024 — Computer simulations by astronomers support the idea that dark matter -- matter that no one has yet directly detected but which many physicists think must be there to explain several aspects of the ...