planet : any of the large bodies that revolve around a star — Webster
Planet is an astronomical body orbiting a star or stellar remnant that
is massive enough to be rounded by its own gravity,
is not massive enough to cause thermonuclear fusion, and
has cleared its neighbouring region of planetesimals.
The term planet is ancient, with ties to history, astrology, science, mythology, and religion. Several planets in the Solar System can be seen with the naked eye. These were regarded by many early cultures as divine, or as emissaries of deities. As scientific knowledge advanced, human perception of the planets changed, incorporating a number of disparate objects. In 2006, the International Astronomical Union (IAU) officially adopted a resolution defining planets within the Solar System. This definition is controversial because it excludes many objects of planetary mass based on where or what they orbit. Although eight of the planetary bodies discovered before 1950 remain “planets” under the modern definition, some celestial bodies, such as Ceres, Pallas, Juno and Vesta (each an object in the solar asteroid belt), and Pluto (the first trans-Neptunian object discovered), that were once considered planets by the scientific community, are no longer viewed as such. — Wikipedia
Dwarf planet is a planetary-mass object that is neither a true planet nor a natural satellite. That is, it is in direct orbit of a star, and is massive enough for its gravity to compress it into a hydrostatically equilibrious shape (usually a spheroid), but has not cleared the neighborhood of other material around its orbit. The term was adopted in 2006 as part of a three-way categorization of bodies orbiting the Sun, brought about by an increase in discoveries of objects farther away from the Sun than Neptune that rivaled Pluto in size, and finally precipitated by the discovery of an even more massive object, Eris. — Wikipedia
Planetary science or, more rarely, planetology, is the scientific study of planets (including Earth), moons, and planetary systems and the processes that form them. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation, interrelations and history. It is a strongly interdisciplinary field, originally growing from astronomy and earth science, but which now incorporates many disciplines, including planetary geology (together with geochemistry and geophysics), cosmochemistry, atmospheric science, oceanography, hydrology, theoretical planetary science, glaciology, and exoplanetology. Allied disciplines include space physics, when concerned with the effects of the Sun on the bodies of the Solar System, and astrobiology. — Wikipedia
Exoplanet or extrasolar planet is a planet outside the Sun’s solar system. The first evidence of an exoplanet was noted as early as 1917, but was not recognized as such. However, the first scientific detection of an exoplanet was in 1988, although it was not confirmed to be an exoplanet until later in 2012. The first confirmed detection occurred in 1992. As of September 2018, there are 3,823 confirmed planets in 2,860 systems, with 632 systems having more than one planet. — Wikipedia
Exoplanet Exploration: Planets Beyond Our Solar System (NASA)
Exoplanet Data Explorer (Exoplanet.org)
What Is an Exoplanet? (Space Place, NASA)
Extrasolar Planets (Ask an Astronomer, Cornell University)
Extrasolar Systems Internet Resources (Library of Congress)
Extrasolar Systems Internet Resources (Library of Congress)
Extrasolar Planets (Eric Weisstein’s World of Astronomy, Wolfram Research)
Exoplanets (Wolfram Alpha)
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
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- Could we learn to love slugs and snails in our...on May 13, 2022 at 3:13 pm
Before you squash or poison the next slug or snail you see in your garden, consider this: The British Royal Horticultural Society no longer classifies these gastropods as pests. Why on earth would a leading gardening organization do that, you might wonder. After all, slugs and snails are usually seen as a problem, given their eagerness to devour the plants you've lovingly nurtured.
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When people talk about ways to slow climate change, they often mention trees, and for good reason. Forests take up a large amount of the planet-warming carbon dioxide that people put into the atmosphere when they burn fossil fuels. But will trees keep up that pace as global temperatures rise? With companies increasingly investing in forests as offsets, saying it cancels out their continuing greenhouse gas emissions, that's a multibillion-dollar question.
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Here are links to pages about closely related subjects.
Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid