Comet

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Posts

  • Octopuses from Space! (5/20/2018)- Did you hear the one about the octopuses from space? It sounds like the title of a cheesy sci-fi movie, doesn’t it? But it isn’t, this time, or at least, yet. Instead, it’s actually an oddball theory that’s been put forth in a recently published “scientific” article that’s getting quite a lot of buzz in … Continue reading Octopuses from Space!
  • RIP Rossetta! (10/1/2016)- The “Little Mission that Could” has come to an end, but what a mission it was to watch! Rosetta Concludes Mission with a Crash (Megan Gannon, Scientific American) Rosetta Mission Ends With Spacecraft’s Dive Into Comet (Kenneth Chang, New York Times) It was such a joy to watch each historic milestone the mission passed over … Continue reading RIP Rossetta!

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General

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Solar System Exploration: Comets (NASA)

Dictionary

comet : a celestial body that appears as a fuzzy head usually surrounding a bright nucleus, that has a usually highly eccentric orbit, that consists primarily of ice and dust, and that often develops one or more long tails when near the sun — Webster

OneLook, Free Dictionary, Wiktionary, Urban Dictionary

Encyclopedia

Comet is a icy small Solar System body that, when passing close to the Sun, warms and begins to evolve gasses, a process called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of solar radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times the Earth’s diameter, while the tail may stretch one astronomical unit. If sufficiently bright, a comet may be seen from the Earth without the aid of a telescope and may subtend an arc of 30° (60 Moons) across the sky. Comets have been observed and recorded since ancient times by many cultures.

Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets originate in the Kuiper belt or its associated scattered disc, which lie beyond the orbit of Neptune. Long-period comets are thought to originate in the Oort cloud, a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star. Long-period comets are set in motion towards the Sun from the Oort cloud by gravitational perturbations caused by passing stars and the galactic tide. Hyperbolic comets may pass once through the inner Solar System before being flung to interstellar space. The appearance of a comet is called an apparition.

Comets are distinguished from asteroids by the presence of an extended, gravitationally unbound atmosphere surrounding their central nucleus. This atmosphere has parts termed the coma (the central part immediately surrounding the nucleus) and the tail (a typically linear section consisting of dust or gas blown out from the coma by the Sun’s light pressure or outstreaming solar wind plasma). However, extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids. Asteroids are thought to have a different origin from comets, having formed inside the orbit of Jupiter rather than in the outer Solar System. The discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets.

As of November 2014 there are 5,253 known comets, a number that is steadily increasing as they are discovered. However, this represents only a tiny fraction of the total potential comet population, as the reservoir of comet-like bodies in the outer Solar System (in the Oort cloud) is estimated to be one trillion. Roughly one comet per year is visible to the naked eye, though many of those are faint and unspectacular. Comets have been visited by unmanned probes such as the European Space Agency’s Rosetta, which became the first ever to land a robotic spacecraft on a comet, and NASA’s Deep Impact, which blasted a crater on Comet Tempel 1 to study its interior. — Wikipedia

Comets (Eric Weisstein’s World of Astronomy, Wolfram Research)
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Comets throughout history (Windows to the Universe)

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WorldCat, Library of Congress, UPenn Online Books, Open Library

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Comets (Cosmos4Kids)
More to Explore: Asteroids, Comets and Meteorites (NASA)
Comets, Meteors & Asteroids (Ask an Astronomer, Cornell University)

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, NPR Archives

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Comet (Minor Planet Center, International Astronomical Union)
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This Perfume Smells Like a Comet (Erin Blakemore, Smithsonian)

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OEDILF: The Omnificent English Dictionary In Limerick Form

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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.

  • Carbonaceous chondrites provide clues about the...
    on February 15, 2019 at 12:38 pm

    An international study led by researchers from the Institute of Space Sciences, from the Spanish National Research Council (CSIC) and the Institut d'Estudis Espacials de Catalunya has discovered that carbonaceous chondrites, a class of meteorites, incorporated hydrated minerals along with organic material from the protoplanetary disk before the formation of planets. The researchers, who have published their results in the journal Space Science Reviews, note that these meteorites played "an […]

  • Asteroid from 'rare species' sighted in the...
    on February 8, 2019 at 1:50 pm

    Astronomers have discovered an asteroid looping through the inner solar system on an exotic orbit. The unusual object is among the first asteroids ever found whose orbit is confined almost entirely within the orbit of Venus. The asteroid's existence hints at potentially significant numbers of space rocks arcing unseen in uncharted regions nearer to the sun. […]

  • Retreating snow line reveals organic molecules...
    on February 5, 2019 at 11:43 am

    Astronomers using ALMA have detected complex organic molecules around the young star V883 Ori. A sudden outburst from this star is releasing molecules from the icy compounds in the planet-forming disk. The chemical composition of the disk is similar to that of comets in the modern solar system. Sensitive ALMA observations enable astronomers to reconstruct the evolution of organic molecules from the birth of the solar system to the objects we see today. […]

  • 'Oumuamua could be the debris cloud of a...
    on February 4, 2019 at 2:06 pm

    Since it was first detected hurling through our solar system, the interstellar object known as 'Oumuamua has been a source of immense scientific interest. Aside from being extrasolar in origin, the fact that it has managed to defy classification time and again has led to some pretty interesting theories. While some have suggested that it is a comet or an asteroid, there has even been the suggestion that it might be an interstellar spacecraft. […]

  • ESA plans mission to smallest asteroid ever...
    on February 4, 2019 at 1:45 pm

    ESA's planet-defending Hera mission will set a new record in space. The asteroid investigator will not only be the first spacecraft to explore a binary asteroid system – the Didymos pair – but the smaller of these two worldlets, comparable in size to Egypt's Great Pyramid of Giza, will become the smallest asteroid ever visited. […]


  • COMET C/2018 Y1 (Iwamoto)
    by Gareth V. Williams on February 16, 2019 at 1:50 am

    M.P.E.C. 2019-D01 Issued 2019 Feb. 16, 01:47 UT The Minor Planet Electronic Circulars contain information on unusual minor planets and routine data on comets. They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Prepared using the Tamkin Foundation Computer Network […]

  • COMET C/2019 A9 (PANSTARRS)
    by Gareth V. Williams on February 7, 2019 at 4:16 pm

    M.P.E.C. 2019-C53 Issued 2019 Feb. 7, 16:08 UT The Minor Planet Electronic Circulars contain information on unusual minor planets and routine data on comets. They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Prepared using the Tamkin Foundation Computer Network […]

  • COMET P/2019 B2 (Groeller)
    by Gareth V. Williams on February 4, 2019 at 4:22 am

    M.P.E.C. 2019-C21 Issued 2019 Feb. 4, 04:02 UT The Minor Planet Electronic Circulars contain information on unusual minor planets and routine data on comets. They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Prepared using the Tamkin Foundation Computer Network […]

  • COMET P/2019 A8 (PANSTARRS)
    by Gareth V. Williams on February 4, 2019 at 3:45 am

    M.P.E.C. 2019-C20 Issued 2019 Feb. 4, 03:32 UT The Minor Planet Electronic Circulars contain information on unusual minor planets and routine data on comets. They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Prepared using the Tamkin Foundation Computer Network […]

  • COMET P/2018 V5 (Trujillo-Sheppard)
    by Gareth V. Williams on February 3, 2019 at 9:20 pm

    M.P.E.C. 2019-C18 Issued 2019 Feb. 3, 20:41 UT The Minor Planet Electronic Circulars contain information on unusual minor planets and routine data on comets. They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Prepared using the Tamkin Foundation Computer Network […]