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


GCSE Astronomy (Lawrence Smallman, YouTube Playlist)


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


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)

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



Articles about Comets (Big Think)




Small Bodies of the Solar System (NASA Science)
Solar System Exploration: Asteroids, Comets & Meteors (NASA)
Asteroids, Comets and Other Small Worlds (Planetary Society)
Comets, Meteors & Asteroids (Ask an Astronomer, Cornell University)

Solar System Exploration: Comets (NASA Science)
Comet Research (NASA)

Deep Impact/EPOXI (NASA)
Deep Impact Mission Page (NASA)
EPOXI Mission Page (NASA)
Deep Impact (Wikipedia)

Giotto Comet Mission (ESA)
Giotto Spacecraft (Wikipedia)



Comets Campaigns (Kickstarter)
Comets Campaigns (Indiegogo)




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


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)




More to Explore: Comets (NASA)
Comets (Cosmos4Kids)
Comets (Space Scoop)

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



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


Comets (JSTOR)
Comet (Minor Planet Center, International Astronomical Union)
Comets (EurekaAlert, AAAS)
Comet (Astronomy Magazine)

Comet (
Comets (NPR Archives)



Comet (



Here are links to pages about closely related subjects.

Knowledge Realm


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

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


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