Mice Galaxies
Encyclopedia
NGC 4676, or the Mice Galaxies, are two spiral galaxies
in the constellation
Coma Berenices
. About 290 million light-year
s away, they are presently in the process of colliding and merging. Their name refers to the long tails produced by tidal action
—the relative difference between gravitational pulls on the near and far parts of each galaxy—known here as a galactic tide
.
Members of the Coma cluster, it is a possibility that both galaxies have experienced collision, and will continue colliding until they coalesce.
The colors of the galaxy are peculiar. In the upper galaxy (NGC 4676A, to the right in the photo), a core with some dark markings is surrounded by a bluish white remnant of spiral arms. The tail is unusual, starting out blue and terminating in a more yellowish color, despite the fact that the beginning of each arm in virtually every spiral galaxy starts yellow and terminates in a bluish color. The lower galaxy (NGC 4676B, to the left) is closer to normal, with a yellowish core and two arcs; arm remnants underneath are bluish as well.
The galaxies were photographed in 2002 by the Hubble Space Telescope
.
Spiral galaxy
A spiral galaxy is a certain kind of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae and, as such, forms part of the Hubble sequence. Spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as...
in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Coma Berenices
Coma Berenices
Coma Berenices is a traditional asterism that has since been defined as one of the 88 modern constellations. It is located near Leo, to which it formerly belonged, and accommodates the North Galactic Pole...
. About 290 million light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s away, they are presently in the process of colliding and merging. Their name refers to the long tails produced by tidal action
Tidal force
The tidal force is a secondary effect of the force of gravity and is responsible for the tides. It arises because the gravitational force per unit mass exerted on one body by a second body is not constant across its diameter, the side nearest to the second being more attracted by it than the side...
—the relative difference between gravitational pulls on the near and far parts of each galaxy—known here as a galactic tide
Galactic tide
A galactic tide is a tidal force experienced by objects subject to the gravitational field of a galaxy such as the Milky Way. Particular areas of interest concerning galactic tides include galactic collisions, the disruption of dwarf or satellite galaxies, and the Milky Way's tidal effect on the...
.
Members of the Coma cluster, it is a possibility that both galaxies have experienced collision, and will continue colliding until they coalesce.
The colors of the galaxy are peculiar. In the upper galaxy (NGC 4676A, to the right in the photo), a core with some dark markings is surrounded by a bluish white remnant of spiral arms. The tail is unusual, starting out blue and terminating in a more yellowish color, despite the fact that the beginning of each arm in virtually every spiral galaxy starts yellow and terminates in a bluish color. The lower galaxy (NGC 4676B, to the left) is closer to normal, with a yellowish core and two arcs; arm remnants underneath are bluish as well.
The galaxies were photographed in 2002 by the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
.