When amateur astronomers turn their telescopes toward Hercules, the usual target is Messier 13, one of the brightest, easiest-to-find globular clusters in the northern sky. But a stone’s throw away is another bright companion – M92 – that runs a close second, containing some 330,000 stars orbiting the Milky Way’s core at a distance of 33,000 light years. Visible to the unaided eye under dark sky conditions, M92 was discovered by Johann Elert Bode in 1777. Four years later, Charles Messier spotted it and added the cluster to his famous catalogue. Neither man could have imagined the splendour revealed by the Hubble Space Telescope as seen in this stunning view.
The Hubble Space Telescope imaged a distant cluster of galaxies that was found by ESA’s Planck satellite, which detected distortions in the cosmic background radiation caused by the cluster’s gravity. Some five billion light years from Earth, the cluster’s members appear as a swarm of red-shifted galaxies, along with an arc of bluish light caused by gravitational lensing.
Hubble Space Telescope observations have taken advantage of gravitational lensing to reveal the largest sample of the faintest and earliest known galaxies in the universe, formed just 600 million years after the Big Bang. Astronomers have determined, for the first time with some confidence, that these small galaxies were vital to creating the universe that we see today.