A galaxy is a gravitationally bound system of stars, interstellar gas, stellar remnants, dust and dark matter. The word galaxy is derived from the Greek term galaxias written as , which literally means "milky", a reference to the Milky Way. Galaxies range in size from dwarfs with just a few hundred million or 108 stars to giants with one hundred trillion or 1014 stars, each orbiting the center of mass of its own galaxy. In the year 2016, a research was released that revised the number of galaxies in the observable universe from a previous estimate of 200 billion, that is, 2×1011 to a suggested two trillion or 2×1012 or possibly even more and, overall, as many as an estimated 1×1024 stars which accounts for more stars than all the grains of sand on planet Earth. Most of the galaxies range from 1,000 to 100,000 parsecs in diameter which equals approximately 3000 to 300,000 light years and are separated by distances on the order of millions of parsecs (or megaparsecs). For comparison, the Milky Way has a diameter of at least 30,000 parsecs, that is, 100,000 light years and is separated from the Andromeda Galaxy, its nearest largest neighbor, by 780,000 parsecs or 2.5 million light years.
In this sub category you can download free PNG images: Galaxy Miscellaneous. In this category "Galaxy" we have 8 free PNG images with transparent background.