The Hubble Space Telescope has taken its deepest-yet look into the cosmos to see some of the earliest galaxies that popped into existence only a few hundred million years after the Big Bang.
The international team that made the discovery also report these tiny primordial galaxies, which are estimated to have formed only 600 million years after the universe came into existence, played an intrinsic role in shaping the cosmos, burning away the smoggy remnants of hydrogen gas that would have blotted out many of these galaxies from view.
These galaxies are therefore giving us a very privileged glimpse into the universe just at the end of the mysterious “re-ionization epoch,” which is thought to have ended around 700 million years after the Big Bang.
To acquire these record-breaking images, Hubble used a neat cosmic trick to boost its magnification. Gravitational lensing is caused by massive clusters of galaxies warping spacetime. Any more distant sources of light, like these newly discovered primordial galaxies that would normally be too faint to see with Hubble’s lens, are boosted through gravitational lensing, allowing astronomers to look deeper into the universe than ever before.
“The faintest galaxies detected in these Hubble observations are fainter than any other yet uncovered in the deepest Hubble observations,” said astronomer Johan Richard from the Observatoire de Lyon, France.
These observations of around 250 previously unseen galaxy comes as a result of the Hubble’s Frontier Fields program that is using gravitational lensing to superboost the space telescope’s capabilities. Often, the images of distant lensed galaxies are seen as arcs, or in very rare cases, complete circles (such as Einstein Rings — where the galactic light is completely warped into a full circle around the lensing galactic cluster).
“Clusters in the Frontier Fields act as powerful natural telescopes and unveil these faint dwarf galaxies that would otherwise be invisible,” said co-author Jean-Paul Kneib, from the Ecole Polytechnique Fédérale de Lausanne, Switzerland.
This groundbreaking observation comes over 25 years since Hubble was launched in 1990, and yet it is still breaking new barriers that no other observatory can currently accomplish.