Birth of the Milky Way

This is an artist's concept of the early years of our Milky Way galaxy, about 12.7 billion years ago. At that time, the majestic spiral arms of our galaxy had not yet formed; the sky was a sea of globular star clusters. The bright blue star cluster at centre left is among hundreds of primeval globular star clusters that came together to build up our galaxy. This particular cluster survives today as the globular cluster M4 in Scorpius. Astronomers used the NASA/ESA Hubble Space Telescope to find the oldest burned-out stars — called white dwarfs — in the cluster. The cluster — chock full young and blue-white stars in this artwork — probably started forming several hundred million years after the Big Bang. On the right of the image, the hub of the Milky Way is beginning to form. Lanes of dark dust encircle a young supermassive black hole and an extragalactic jet of high-speed material beams into space from the young black hole, which is feeding on stars, gas and dust. A string of supernova explosions from the most massive stars in the cluster creates pink bubbles of hot gas around each star cluster.