General astronomy

General astronomy

Contributors in General astronomy

General astronomy

Small rocky and/or icy particles that are swept up by the earth in its orbit about the sun. Also called "shooting stars", they travel across the sky in a very short time, from less than a second to ...

Magnitude

Astronomy; General astronomy

The units used to describe brightness of astronomical objects. The smaller the numerical value, the brighter the object. The human eye can detect stars to 6th or 7th magnitude on a dark, clear night ...

m2

Astronomy; General astronomy

The magnitude value measured (or predicted) for a comet's nuclear condensation. Note that the true comet nucleus is rarely, if ever, directly observed from the earth because of the large amount of ...

m1

Astronomy; General astronomy

Total, integrated magnitude of a comet's head (meaning coma + nuclear condensation). This can be estimated visually, as the comet's "total visual magnitude". The variable m 1 is usually found in ...

Light pollution

Astronomy; General astronomy

The emission of stray light or glare from lighting fixtures in manners that counter the purpose of the light (which is to light what is below); also known as the waste of money and energy in the form ...

julian year

Astronomy; General astronomy

Exactly 365.25 days, in which a century (100 years) is exactly 36525 days and in which 1900.0 corresponds exactly to 1900 January 0.5 (from the Julian-date system, which is half a day different from ...

heliocentric

Astronomy; General astronomy

Referring to the sun. A heliocentric orbit is one based on the sun as one of the two foci of the (elliptical) orbit (or as the center of a circular orbit); a heliocentric magnitude is the brightness ...