Reference Terms
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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
November 19, 2024
Nov. 13, 2024 — An asteroid struck Mars 11 million years ago and sent pieces of the red planet hurtling through space. One of these chunks of Mars eventually crashed into the Earth and is one of the few meteorites that can be traced directly to Mars. This meteorite ...
Nov. 13, 2024 — Astronomers have identified three ultra-massive galaxies -- nearly as massive as the Milky Way -- already in place within the first billion years after the Big Bang. This surprising discovery was made possible by the James Webb Space Telescope's ...
Nov. 4, 2024 — Astronomers have discovered a supermassive black hole at the center of a galaxy just 1.5 billion years after the Big Bang that is consuming matter at a phenomenal rate -- over 40 times the theoretical limit. While short lived, this black hole's ...
Oct. 30, 2024 — New research in our Milky Way has revealed a neutron star that rotates around its axis at an extremely high speed. It spins 716 times per second, making it one of the fastest-spinning objects ever ...
Latest Headlines
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Nov. 18, 2024 — New research found confined and isolating environments changed the way people smelled and responded emotionally to certain food aromas. The team in this study compared 44 people's emotional responses ...
Nov. 18, 2024 — Through the intricate study of lava tubes -- caves formed following volcanic eruptions when lava cools down -- an international team of researchers has uncovered clues about Earth's ancient ...
Nov. 18, 2024 — A theoretical astrophysicist may have solved a nearly two-decade-old mystery over the origins of an unusual 'zebra' pattern seen in high-frequency radio pulses from the Crab ...
Nov. 14, 2024 — By probing chemical processes observed in the Earth's hot mantle, scientists have started developing a library of basalt-based spectral signatures that not only will help reveal the composition of ...
Nov. 14, 2024 — How long did it take our Sun to form in its stellar nursery? Scientists are now closer to an answer. They succeeded in the measurement of the ...
Nov. 13, 2024 — Scientists using observations from NASA's Neil Gehrels Swift Observatory have discovered, for the first time, the signal from a pair of monster black holes disrupting a cloud of gas in the center of ...
Nov. 12, 2024 — The chances of intelligent life emerging in our Universe -- and in any hypothetical ones beyond it -- can be estimated by a new theoretical model ...
Nov. 12, 2024 — A team combined compositional data of primitive bodies like Kuiper Belt objects, asteroids and comets with new solar data sets to develop a revised solar composition that potentially reconciles ...
Nov. 12, 2024 — The standard model for how galaxies formed in the early universe predicted that the James Webb Space Telescope (JWST) would see dim signals from small, primitive galaxies. But data are not confirming ...
Nov. 11, 2024 — Like the Earth, the Sun likely has swirling polar vortices, according to new research. But unlike on Earth, the formation and evolution of these vortices are driven by magnetic ...