Galaxies are not evenly distributed

Galaxies are not evenly distributed throughout the universe. A few are found alone, but almost all are
grouped in formations termed galactic clusters. These formations should not be confused with stellar
clusters, globular clusters of stars that exist within a galaxy. The size of galactic clusters varies
enormously, with some clusters containing only a dozen or so members and others containing as many as
10,000. Moreover, galactic clusters themselves are part of larger clusters of clusters, termed
superclusters. It is surmised that even clusters of superclusters are possible.
Our galaxy, the Milky Way, is part of a galactic cluster called the Local Group, which has twenty
members and is typical in terms of the types of galaxies it contains. There are three large spiral galaxies:
Andromeda, the largest galaxy in the group; the Milky Way, the second-largest galaxy; and the Trianglum
Spiral, the third largest. There are also four medium-sized spiral galaxies, including the Large Cloud of
Magellan and the Small Cloud of Magellan. There are four regular elliptical galaxies; the remainders are
dwarf ellipticals. Other than our own galaxy, only Andromeda and the Clouds of Magellan can be seen
with the naked eye, and the Clouds are visible only from the Southern Hemisphere.
In the vicinity of the Local Group are several clusters, each containing around twelve members. The
nearest cluster rich in members is the Virgo Cluster, which contains thousands of galaxies of all types.
Like most large clusters, it emits X-rays. The Local Group, the small neighboring clusters, and the Virgo
Cluster form part of a much larger cluster of clusters – the Local Supercluster.
The existence of galactic clusters presented a riddle to scientists for many years – the “missing mass”
problem. Clusters are presumably held together by the gravity generated by their members. However,
measurements showed that the galaxies did not have enough mass to explain their apparent stability. Why
didn’t these clusters disintegrate? It is now thought that galaxies contain great amounts of “dark matter”,
which cannot be directly observed but which generates gravitational pull.
This matter includes gas, dust, burnt-out stars, and even black holes.

Kết quả (Anh) 1:

Galaxies are not evenly distributed throughout the universe. A few are found alone, but almost all are grouped in formations termed galactic clusters. These formations should not be confused with stellar clusters, globular clusters of stars that exist within a galaxy. The size of galactic clusters varies enormously, with some clusters containing only a dozen or so members and others containing as many as 10.000. Moreover, galactic clusters themselves are part of larger clusters of clusters, termed superclusters. It is surmised that even clusters of superclusters are possible. Our galaxy, the Milky Way, is part of a galactic cluster called the Local Group, which has twenty members and is typical in terms of the types of galaxies it contains. There are three large spiral galaxies: Andromeda, the largest galaxy in the group; the Milky Way, the second-largest galaxy; and the Trianglum Spiral, the third largest. There are also four medium-sized spiral galaxies, including the Large Cloud of Magellan and the Small Cloud of Magellan. There are four regular elliptical galaxies; the remainders are Dwarf ellipticals. Other than our own galaxy, Andromeda and the only Clouds of Magellan can be seen with the naked eye, and the Clouds are visible only from the Southern Hemisphere. In the vicinity of the Local Group are several clusters, each containing around twelve members. The nearest cluster rich in members is the Virgo Cluster, which contains thousands of galaxies of all types. Like most large clusters, it emits X-rays. The Local Group, the small neighboring clusters, and the Virgo Cluster form part of a much larger cluster of clusters – the Local Supercluster. The existence of galactic clusters presented a riddle to scientists for many years – the “missing mass” problem. Clusters are presumably held together by the gravity generated by their members. However, measurements showed that the galaxies did not have enough mass to explain their apparent stability. Why didn’t these clusters disintegrate? It is now thought that galaxies contain great amounts of “dark matter”, which cannot be directly observed but which generates gravitational pull. This matter includes gas, dust, burnt-out stars, and even black holes.