Reference Terms
from Wikipedia, the free encyclopedia
Definition of planet
The definition of "planet" has for some time been the subject of intense debate.
Note: The above text is excerpted from the Wikipedia article "Definition of planet", which has been released under the GNU Free Documentation License.
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Space & Time News
January 19, 2025
Jan. 17, 2025 — The Universe really seems to be expanding fast. Too fast, even. A new measurement confirms what previous -- and highly debated -- results had shown: The Universe is expanding faster than predicted by ...
Jan. 17, 2025 — In the years following the launch of NASA's Hubble Space Telescope, astronomers have tallied over 1 trillion galaxies in the universe. But only one galaxy stands out as the most important nearby stellar island to our Milky Way -- the magnificent ...
Jan. 17, 2025 — Astrophysicists have imaged a large number of exocomet belts around nearby stars, and the tiny pebbles within them. The crystal-clear images show light being emitted from these millimeter-sized ...
Jan. 16, 2025 — In 2018, a galaxy about 270 million light-years away from Earth exhibited a major increase in activity. It quieted down again by 2020 -- only to dramatically increase its output again in 2023. At ...
Latest Headlines
updated 12:56 pm ET
Jan. 16, 2025 — Galaxies like the Milky Way grow by merging with smaller galaxies over billions of years, unlike dwarf galaxies, which have long been thought to lack the heft to attract mass and grow in the same ...
Jan. 16, 2025 — Leo P, a small galaxy and a distant neighbor of the Milky Way, is lighting the way for astronomers to better understand star formation and how a galaxy grows. Scientists have reported finding that ...
Jan. 16, 2025 — Pandora, a small satellite mission poised to provide in-depth study of at least 20 known planets orbiting distant stars to determine the composition of their atmospheres cleared an important ...
Jan. 16, 2025 — A research team has discovered another piece in the puzzle of the formation of the Moon and water on Earth. The prevailing theory was that the Moon was the result of a collision between the early ...
Jan. 15, 2025 — A new analysis of data from the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) reveals fresh evidence that collisions of even very small nuclei with large ones might create tiny ...
Jan. 15, 2025 — By combining data from the DESI Legacy Imaging Surveys and the Gemini South telescope, astronomers have investigated three ultra-faint dwarf galaxies that reside in a region of space isolated from ...
Jan. 15, 2025 — For humans, the most important star in the universe is our Sun. The second-most important star is nestled inside the Andromeda galaxy. Don't go looking for it -- the flickering star is 2.2 million ...
Jan. 15, 2025 — Astronomers have detected an intensely brightening and dimming quasar that may help explain how some objects in the early universe grew at a highly accelerated rate. The discovery is the most distant ...
Jan. 15, 2025 — New observational data and simulation models have confirmed a new type of planet unlike anything found in the Solar System. This provides another piece of the puzzle to understand how planets and ...
Jan. 15, 2025 — Hot Jupiters are giant planets initially known to orbit alone close to their star. During their migration towards their star, these planets were thought to accrete or eject any other planets present. ...