Comet

Cosma / Communication / Knowledge / Realm / Physical / Universe / Solar System / Small Body / Comet
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Introduction1

GCSE Astronomy (Lawrence Smallman, YouTube Playlist)

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 — Merriam-Webster   See also   OneLook

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. — Wikipedia

Comet (Encyclopædia Britannica)

Comet (COSMOS: The SAO Encyclopedia of Astronomy)

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Inspiration

NASA’s Eyes is a freely available suite of computer visualization applications created by the Visualization Technology Applications and Development Team at NASA’s Jet Propulsion Laboratory (JPL) to render scientifically accurate views of the planets studied by JPL missions and the spacecraft used in that study. Eyes on Astroids provides real-time visualization of every known asteroid or coment that is classified as a Near-Earth Object (NEO). You can also explore most of NASA’s asteroid and comet missions (past and present), from Galileo , to Lucy and DART.– Wikipedia

Eyes on Asteroids (NASA’s Eyes on the Solar System, NASA’s JPL & Cal Tech)

Halley’s Comet (NASA’s Eyes on the Solar System, NASA’s JPL & Cal Tech)
Comet 9P/Tempel 1 (NASA’s Eyes on the Solar System, NASA’s JPL & Cal Tech)
Comet 67P/ Churyumov-Gerasimenko (NASA’s Eyes on the Solar System, NASA’s JPL & Cal Tech)
Comet Hartley 2 (NASA’s Eyes on the Solar System, NASA’s JPL & Cal Tech)

Comets (Astrum, YouTube Playlist)

Articles about Comets (Big Think)

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Innovation

Science

Solar System Exploration: Comets (NASA Science)
Asteroids, Comets & Meteors (NASA Science)
Small Bodies of the Solar System (NASA Science)

Comet Videos (ViewSpace, Space Telescope Science Institute)

Object Search (International Astronomical Union)

Comets (Mike Brown’s Planets)

Comets (Eric Weisstein’s World of Astronomy, Wolfram Research)
Comets (Wolfram Alpha)

Commerce

Entrepreneurship

Comets Campaigns (Kickstarter)

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Preservation

History

Cometographia (Objectivity, YouTube Video)
The Comet Hunter (Objectivity, YouTube Video)

Comet History (Encyclopædia Britannica)
Comets (World History Encyclopedia)

Library

DDC: 523.6 Comets (Library Thing)
Subject: Comets (Library Thing)

Subject: Comets (Open Library)

LCC: QB 717 Comets (UPenn Online Books)

LCC: QB 717 Comets (Library of Congress)
Subject: Comets (Library of Congress)

Subject: Comets (WorldCat)

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Participation

Education

Comets – Level 1 (StarChild, Goddard Space Flight Center, NASA)
Comets – Level 2 (StarChild, Goddard Space Flight Center, NASA)

Comets (Cosmos4Kids)
Comets (Space Scoop)

Asteroids, Comets, and Meteorites (Lunar & Planetary Institute)
Asteroids and Comets (Science Trek)

Comets (Crash Course Astronomy, YouTube Video)

MERLOT: Multimedia Educational Resource for Learning and Online Teaching
OER Commons: Open Educational Resources

Community

Organization

Minor Planet Center (International Astronomical Union)
Comet Section (British Astronomical Association)

News

Comets (Minor Planet Center, International Astronomical Union)
Comets (Nova Research Highlights, American Astronomical Society)
Comets (EurekaAlert, AAAS)
Comets (JSTOR)
Comets (Astronomy Magazine)
Comets (Phys.org)

Recent News from Phys.org …

  • Could the Milky Way's missing mass be hiding in a...
    on June 7, 2026 at 9:00 pm

    3I/ATLAS has caused quite a stir over the last year, inviting astronomers to update what they know about other solar systems as well as our own. However, this third interstellar visitor may have an unexpected impact on our understanding of dark matter. A new paper, available on the arXiv preprint server from researchers at the University of Hamburg, attempts to calculate the impact that the presence of large amounts of interstellar objects, or ISOs, would have on our calculation of dark matter […]

  • Meteors are 'extremely common.' What makes the...
    on June 4, 2026 at 2:20 pm

    A sonic boom shook Boston and the larger New England area with the force of 230 tons of TNT. The source came from outer space. The Saturday afternoon event triggered shock waves online, with thousands inquiring what could have caused houses to shake and a sound heard as far away as New Hampshire and Rhode Island.

  • Interstellar object 3I/ATLAS reveals no...
    on June 3, 2026 at 10:30 pm

    Scientists at the SETI Institute recently searched for technological signals from 3I/ATLAS, the third interstellar object observed in our solar system. Using the Allen Telescope Array (ATA) at the Hat Creek Radio Observatory in Northern California, the team scanned a wide range of radio frequencies for signs of extraterrestrial technology and found none, as expected based on other astronomical observations showing that the object exhibits natural comet-like composition and behavior. The paper […]

  • Mars mission ends: NASA declares Maven dead after...
    on June 3, 2026 at 4:19 pm

    After six months of radio silence, NASA's Maven spacecraft around Mars has been declared dead.

  • Bare supercontinent may have tipped ancient Earth...
    on May 28, 2026 at 3:20 pm

    About a billion years ago, Earth started to come into its own. It was past the awkwardness of its younger years full of growing pains and turmoil: comet strikes and slimy water, including the Great Oxidation Event that flipped the world upside down. Roughly a billion years ago, the planet began to advance and mature, with plant life developing about 700 million years ago, but still with the occasional wild climate parties to keep things interesting.

returntotop

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Related

Here are links to pages about closely related subjects.

Knowledge Realm

Physical

“Fundamentals”
Law (Constant) Relativity
Force Gravity, Electromagnetism (Light, Color)
Matter (Microscope) Molecule, Atom (Periodic Table), Particle

“Space”
Universe (Astronomical Instrument)
Galaxy Milky Way, Andromeda
Planetary System Star, Brown Dwarf, Planet, Moon

Our Neighborhood
Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Trans-Neptunian Object
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid

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Notes

1.   The resources on this page are are organized by a classification scheme developed exclusively for Cosma.