Comet

Comet

A comet is an icy, small Solar System body or interstellar object that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and sometimes a tail of gas and dust gas blown out from the coma. These phenomena are due to the effects of solar radiation and the outstreaming solar wind plasma acting upon the nucleus of the comet. Comet nuclei range from a few hundred meters to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times Earth's diameter, while the tail may stretch beyond one astronomical unit. If sufficiently close and bright, a comet may be seen from Earth without the aid of a telescope and can subtend an arc of up to 30° across the sky. Comets have been observed and recorded since ancient times by many cultures and religions.

Comet (tank)

The Comet tank or Tank, Cruiser, Comet I (A34) was a British cruiser tank that first saw use near the end of the Second World War, during the Western Allied invasion of Germany. The Comet was developed from the earlier Cromwell tank with a lower profile, partly-cast turret which mounted the new 77 mm HV gun. This was a smaller version of the 17 pdr anti-tank gun firing the same 76.2 mm (3") projectiles, albeit with a lighter charge, and was effective against late-war German tanks, including the Panther and Tiger.

Comet

Proper noun

1. The fifth reindeer of Santa Claus.

Proper noun

1. A web application model in which a long-held HTTP request allows a web server to push data to a browser, without the browser explicitly requesting it.