Galaxy - it's huge gravitational system,composed of stars, gas and dust, and dark matter clusters. They have gigantic dimensions: our Milky Way galaxy is not considered large, but has a diameter of 100 thousand light years.
There are much more massive objects, the average of their sizes range from 16 to 800 thousand light-years.
The largest known galaxy has a diameter of about 6 million light-years.
The largest galaxy
A light-year - the standard measurement of the value ofstate space. This is the way that light, moving at the speed limit in the universe overcomes the year. Our galaxy is a spiral shape, its diameter is about 100 thousand light-years: so much time you need light to fly from one end through the center to the other.
But this is not the largest education, many galaxies have sizes of a few hundred thousand light-years, and sometimes more than a million.
Largest of the detected galaxies is instar cluster Abell 2029. It is located at a distance of more than a billion light years from Earth, so looks like a small point in the constellation Virgo, but in reality it is an incredibly huge Lenticular education. Perhaps now it has changed a bit, because the observer see the light emanating from it a billion years ago. She does not have a traditional name, it is IC 1101 number.
For the first time this galaxy seen through the telescope famous English astronomer William Herschel in 1790.
The diameter of the IC 1101 - about 6 million light-years,while there was no galaxies with greater width. Perhaps this is the most massive star formation in the universe: it is 2000 times the mass of the Milky Way, consists of a hundred trillion stars and planets, and contains a large amount of dark matter. If we compare it with the weight of the Sun, it is a few quadrillion times larger and heavier. Scientists say that if you put the IC 1101 in place of the Milky Way, it would be captured and the surrounding galaxy - Andromeda, Triangle, Small and Large Magellanic Clouds, and in fact they are an incredibly large distances from the Earth.
IC 1101 and formed: it collides with other objects that were smaller and literally captured them with their gravity. Astronomers call such galaxies cosmic predators: they are ready to absorb all that will meet on their way to the smaller mass and dimensions.
Other major galaxy
Hercules-A is the second-largestgalaxies, although its diameter is much smaller - about 1.5 million light-years. But it is a thousand times greater than the Milky Way, and the black hole at its center is a thousand times more massive than the black hole in our galaxy. 1.3 million light years - the size of NGC 262, a spiral star in the constellation Andromeda. This is 13 times greater than the Milky Way.
Scientists can detect galaxies onlythe observable universe, but even in her field to search for another huge, it found only a fraction of all existing facilities. A total of over a hundred billion, according to the assumptions of the researchers, and among them may be even larger galaxy.