The picture covers a patch of sky about as big as a grain of sand held at arm’s length. Inside it sit thousands of galaxies.
That was the first full image from the James Webb Space Telescope, a deep field aimed at a cluster called SMACS 0723 in the southern constellation of Volans. President Joe Biden showed it during a NASA livestream at 6:15 p.m. EDT on July 11, 2022. The rest of Webb’s first photos followed the next morning at 10:30 a.m. EDT.
For many people watching, it was the moment a project that began in 1996, and had been dogged by delays and setbacks, finally paid off. ScienceAlert called it the deepest infrared view of the universe ever taken.
A cluster that works like a lens
The choice of target was deliberate. SMACS 0723 has massive galaxy clusters in the foreground, and their weight bends the space around them. That bending magnifies light from objects far behind, so the cluster acts as a giant cosmic magnifying glass.
Gravitational lenses have produced sharp views of the distant universe before. This one, built from 12.5 hours of exposure time, showed many galaxies for the first time, including the faintest objects ever recorded in infrared. Hubble had also looked at this region, and Webb was expected to reveal more of it.
What astronomers saw
Cathryn Trott, an astronomer at the International Centre for Radio Astronomy Research who was not part of the research, told Scimex the image gives the first clear look at some of the earliest galaxies. “This image captures the starlight from the earliest objects to have formed in the first few hundred million years after the Big Bang,” she said. That light is more than 13 billion years old, and the foreground cluster focused it toward Webb.
Fred Watson, an Australian astronomer, said astronomers had grown used to Hubble images of distant clusters ringed by warped, even more distant galaxies. “But the first released image from the Webb telescope takes us into a breathtaking new regime of detail and depth,” he said, adding that it was “a stunning taster of what is to come.”
Paulo de Souza, Dean of Research at Griffith Sciences at Griffith University, put the age of the image in human terms. Everything in it was set nearly 13 billion years ago, he told Scimex. “Right now, we could well have nothing left there,” he said. “This image is a snapshot of a distant past.”
Webb’s mission includes questions Watson listed himself: when the first stars and galaxies formed, how they evolved, and whether planets orbiting stars near the Sun could harbor life.
