Galaxy Facts
Galaxies are groups of billions of stars that are held together by forces of gravity.Most galaxies are either spiral or elliprtical,but some are irregular in ahape.
The Milky Way Galaxy:
The Best known galaxy is the Milky way galaxy.This Galaxy is 100,000 light years in diameter. The word galaxy itself comes from the Greek word for milk.This is because before Telescopes were powerful enough to prove that they were made up of individual stars, galaxies looked like milky or cloudy areas in the sky. Our relatively small solar system is one of the billions of 100-200 billions of stars in the galaxy.The Sun and all the planets take about 200,000,000 years to complete one orbit around its centre.
Brightest Galaxy:
The Largest Magellanic Cloud, which is visible only in the southern hemisphere,is 170,000 light years from Earth and 39,000 light years in diameter.
Largest Galaxy:
The Central galaxy of the Abell 2029galaxy cluster was discovered in 1990.It is 1,070 million light years distant and has a diameter of 5.6 million years, 80 time the diameter of our own galaxy.It has a total light output equivalent to 2 trillion times that of the Sun.
Nearest Galaxy:
The Sagittarius Dwarf, discovered in 1994, is more than 70,000 light years (660 quadrillion km) from Earth, and is being torn apart.
Remotest visibile object:
The most distant thing in the Universe that can be seen with the naked eye is the Andromeda Galaxy, which is 2,309,000 light years from Earth.This galaxy has 300 billion stars and a diameter of 180,000 light years. The light we see now from Andromeda left there just after the first humans appear on Earth.
Most Distant Galaxy:
In 2004,astronomers at the European Southern Observatory,chille,announced the discovery of Galaxy Abell 135 IR1916. It exists an astonishing 13.2 billion light years from Earth.