In this composite image, several galaxies are represented by red dots appearing together as a cluster. NASA says this image shows this cluster as it existed 9.6 billion years ago, which was 3 billion years after the Big Bang. As NASA writes, “Astronomers were surprised to find such a modern cluster at an era when its peers tended to be much smaller, presumably taking billions of more years to collect enough galaxies to reach such a size.” A galaxy is defined of a massive gravitationally bound system of stars, gas dust and dark matter, among other objects. Galaxies can be many different shapes, including spiral, elliptical, starburst and even irregular.