transit

transit, in astronomy, passage of a body across a meridian or passage of a small body across the visible disk of a larger one. (The passage of a large body across a smaller one is called an eclipse or occultation.) All of the fixed stars transit the celestial meridian once daily; an observer can determine either his longitude or the sidereal time by noting the time at which a given star transits his meridian and by referring to tables. Transits of small bodies across larger ones can be observed only within the bounds of the solar system. The innermost moons of Jupiter are so close to the planet that they transit it at every orbit. Of the planets, only Mercury and Venus, whose orbits lie inside the earth's orbit, can transit the sun. When such a transit occurs, the planet appears in a special solar telescope as a small black dot on the sun's disk. A solar transit can occur only when one of the two planets is in inferior conjunction and at one of its nodes on the plane of the ecliptic. For Mercury, solar transit can occur only in May or November. The interval between November transits is 7, 13, or 46 years; May transits occur at intervals of 13 or 46 years. Exact timing of Mercury's transits have offered experimental confirmation of the theory of relativity. For Venus, solar transit occurs in June or December. Currently, two transits take place within about 8 years of each other, with an interval of 521/2 or 601/2 years between pairs of transits. The next two solar transits of Venus will occur in June, 2004, and June, 2012. Venus's solar transits have been used in determining the astronomical unit.

Transportation systems, usually publicly but sometimes privately owned and operated, designed to move large numbers of people in various types of vehicles in cities, suburbs, and large metropolitan areas. Modern mass transit is an outgrowth of industrialization and urbanization. In the 1830s early mass transit in New York City included horse-drawn buses, which were soon replaced by fixed-rail horse-drawn trolleys. By 1900 motorized buses had appeared in Europe and America. With the advent of electricity, streetcars and subways were introduced in many large cities. In the 20th century the automobile's increasing popularity undermined mass transit development; fixed-rail streetcar systems were widely removed to provide space for cars. Concern over air pollution has revived interest in light-rail transit and has led to regional mass transit systems.

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Transit may refer to:

Media

• Transit (film), a 2006 film about Russian and American pilots in World War II
• Transit (Sponge Cola album), an album by Sponge Cola
• Transit (Staying-Alive film), a film produced by MTV and Staying-Alive about 4 people in different countries in the world.

Transportation

• Astronomical transit, when one celestial body appears to move across the face of another celestial body, as seen by an observer at some particular vantage point
• Ford Transit, a van made by the Ford Motor Company
• Mass transit, transportation systems in which the passengers do not travel in their own vehicles
• Navigational transit, when a navigator observes two fixed reference points in line
• Transit (ship), the name given to three sailing vessels designed and built to the order of Captain Richard Hall Gower
• A specialized type of Theodolite used in surveying.
• Transit New Zealand, a crown entity responsible for the New Zealand national state highway network.

Other uses

• Transit, Canadian shoe retailer now operating under the name Spring
• Astrological transit, are the comparison and evaluation of planets in their current position in relation to those on a Natal Chart.
• Transit, a 1992 novel by Ben Aaronovitch based on the TV series Doctor Who
• Transit (satellite), the first satellite navigation system to be used operationally
• Internet transit, one of the two mechanisms by which Internet traffic is exchanged between internet service providers
• Routing transit number, an identifying code used in transference of funds through banking institutions