James Webb Space Telescope snaps deepest space image ever
The first full-colour image from the James Webb Space Telescope (JWST) has been unveiled by NASA and President Joe Biden and is the deepest and most detailed image of the universe ever captured. Named Webb’s First Deep Field, the spectacular and mindbending photo shows our universe only a few hundred million years after the Big Bang, just as galaxies began to form and light started flickering from the very first stars. This starlight has taken roughly 13.5 billion years – or most of the age of the universe – to travel to us, arriving at the James Webb Space Telescope after the space-time warping gravitational pull of the galaxy cluster SMACS 0723 steered even the fainter and more distant light into focus.
“We’re going back 13.5 billion years,” said NASA administrator Bill Nelson. “And since we know the universe is 13.8 billion years old, we’re going back almost to the beginning.” Nelson added that the telescope “is going to be so precise we are going to see whether or not planets are habitable,” and that its unprecedented views of the universe would enable scientists to find answers to questions that haven’t even been asked yet. Remarkably, despite the overwhelming density of galaxies, stars and potential planets contained within the image, it’s just the tiniest slice of the night sky.
The previous record holder for capturing the deepest and oldest glimpse into space is the Hubble Space Telescope. Its series of deep fields showed how several hundred million years after the Big Bang, galaxies of glistening stars had already coalesced in our young universe. But to peer even further back in time, scientists needed to design a telescope both large enough to capture light from the faintest objects and capable of detecting the mid-infrared frequencies that the most distant light has been shifted to by the universe’s expansion.
Enter the James Webb Space Telescope.
Its primary mirror diameter measures 6.6 metres wide, compared with Hubble’s mirror which is just 2.4 metres in diameter. This means Webb is capable of detecting objects 100 times fainter than Hubble could see.
The telescope can also scan the universe in infrared, enabling it to glimpse galaxies that were born a mere 200 million years after the Big Bang.
Webb’s extreme sensitivity to infrared frequencies meant that it needed to be isolated from disruptive heat signals on Earth. It now rests at a gravitationally stable location beyond the Moon’s orbit – known as a Lagrange point – after being launched there from French Guiana atop an Ariane 5 rocket on Christmas Day 2021. Across the six months following its launch, NASA engineers calibrated the telescope’s instruments and mirror segments in preparation for snapping the first images. Their progress was briefly interrupted after the telescope was unexpectedly struck by a micrometeoroid sometime between 23 and 25 May, but the impact did not damage the spacecraft. The image is the first of many to be collected by Webb. NASA has released four more images offering views of a stellar nursery, the atmosphere of a distant exoplanet, a figureeight-shaped gas explosion from a dying star and a quintet of galaxies locked in a cosmic dance of endless near-collisions.