Geocentric Coordinate Time system. When the Earth is at perihelion in January, TCG ticks even more slowly than it does on average, due to gravitational time dilation from being deeper in the Sun's gravity well and also velocity time dilation from moving faster relative to the Sun. At aphelion in July the opposite holds, with TCG ticking faster than it does on average. Geocentric Coordinate Time Geocentric Coordinate Time (TCG - Temps-coordonnée géocentrique) is a coordinate time standard intended to be used as the independent variable of time for all calculations pertaining to precession, nutation, the Moon, and artificial satellites of the Earth.
National Register of Historic Places listings in Central Chicago National Register of Historic Places listings in Central Chicago Currently there are 124 National Register of Historic Places listings in Central Chicago, out of 354 listings in the City of Chicago. Central Chicago includes 3 of the 77 well-defined community areas of Chicago: the historic business and cultural center of Chicago known as the Loop, as well as the Near North Side and the Near South Side. The combined area is bounded by Lake Michigan on the east, the Chicago River on the west, North Avenue (1600 N.) on the north, and 26th Street (2600 S.) on the south. This