Webb draws back curtain on Universe’s early galaxies

The powerful NASA/ESA/CSA James Webb Space Telescope has found an unexpectedly rich ‘undiscovered country’ of early galaxies that has been largely hidden until now.

A few days after officially starting science operations, Webb propelled astronomers into a realm of early galaxies, previously hidden beyond the grasp of all other telescopes. Webb is now unveiling a very rich Universe where the first forming galaxies look remarkably different from the mature galaxies seen around us today.

Researchers have found two exceptionally bright galaxies that existed approximately 300 and 400 million years after the Big Bang. Their extreme brightness is puzzling to astronomers.

The young galaxies are transforming gas into stars as fast as they can and they appear compacted into spherical or disc shapes that are much smaller than our Milky Way galaxy. The onset of stellar birth may have been just 100 million years after the Big Bang, which happened 13.8 billion years ago.

Two of the most distant galaxies seen to date are captured in these Webb pictures of the outer regions of the giant galaxy cluster Abell 2744. The galaxies are not inside the cluster, but many billions of light-years behind it.

The galaxy featured in the image at the top centre is extracted from the image on the left. It existed only 450 million years after the Big Bang.

The galaxy featured in the image at the bottom centre is extracted from the image on the right. It existed 350 million years after the Big Bang.

Both galaxies are seen really close in time to the Big Bang which occurred 13.8 billion years ago. These galaxies are tiny compared to our Milky Way, being just a few percent of its size, even the unexpectedly elongated galaxy showcased in the top centre image.

More information about this image

Webb is the largest, most powerful telescope ever launched into space. Under an international collaboration agreement, ESA provided the telescope’s launch service, using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service by Arianespace. ESA also provided the workhorse spectrograph NIRSpec and 50% of the mid-infrared instrument MIRI, which was designed and built by a consortium of nationally funded European Institutes (The MIRI European Consortium) in partnership with JPL and the University of Arizona. Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).