Side-by-side comparisons highlight visual gains
You’ve no doubt already seen the first batch of images of NASA’s powerful new eye in the sky, the James Webb Space Telescope. But the scope of achievement can be difficult to appreciate without context, so here they are side by side with Hubble’s views of the same regions.
The scientific world has been abuzz over Webb’s new images, but you’d be forgiven for thinking quietly, “what’s the deal?” After all, audiences have gotten used to seeing stunning images of the cosmos over the decades, and at a glance, these new images don’t necessarily look that different. It’s only when placed right next to existing images that the technological advancements become startlingly clear.
This structure, which NASA calls the Cosmic Cliffs, is actually the inner edge of NGC 3324, aka the Carina Nebula. Ultraviolet radiation and powerful stellar winds from a dying star — located high above the top of the frame in this image — are carving these structures into clouds of dust and gas that are actively forming new stars.
Using its infrared vision, the Webb image below reveals for the first time many of these baby stars shining through the dust, the younger ones visible as red dots in the darker parts of the cloud.
South Ring Nebula
NGC 3132, better known as the South Ring Nebula, is an expanding cloud of gas thrown up by a dying star about 2,500 light-years from Earth. The bright star in the center may look like the culprit, but it’s not – that honor belongs to the much fainter star right next to it.
The image on the left is the southern ring as seen by Hubble in an image released in 1998. The image by James Webb on the right provides a marked improvement in resolution, bringing cloud detail into focus and revealing that the star darker is actually enveloped in its own little cloud of dust.
This cluster of five galaxies, known as Stephan’s Quintet, appears to show five galaxies locked in a cosmic dance. However, it should be noted that the leftmost galaxy is actually far from the others – it is 250 million light-years closer to Earth than the others. It happens to be in the same corner of the sky.
Yet Webb was able to image the five galaxies in much greater detail than ever before, peering into their very cores. There are supermassive black holes swallowing dust and gas, visible as bright spots at the center of each galaxy. The new image reveals the flow of gas as galaxies begin to merge, triggering star formation and sending shockwaves through the system.
It is also Webb’s largest image, a mosaic of nearly 1,000 files put together into an image made up of more than 150 million pixels and covering an area about one-fifth the diameter of the Moon.
From Webb’s largest image to its smallest, the telescope’s view of galaxy cluster SMACS 0723 is a slice of sky covering the area of a grain of sand held at arm’s length. This is Webb’s first Deep Field image, looking deeper into space and time than Hubble is capable of.
The Hubble image on the left shows many faint stars and galaxies, but the Webb image on the right absolutely pops with light, revealing many hidden structures. In particular, the redder galaxies are those that are further away, with the wavelengths of their light stretched towards the red end by the expansion of the universe. As such, many of them are outside of Hubble’s field of view.
The gravitational lensing effect, visible as a circular smear of light in the center of the frame, is also much clearer in Webb’s image. The mass of the cluster physically distorts the fabric of spacetime with its immense gravity, bending and magnifying light from other sources behind it. Webb will be able to use this effect to observe even deeper in space, and as such, further out in time, than any other telescope so far.
The first image of the Webb telescope, in context! (SMACS 0723 in WWT)
But perhaps the most striking context for Webb’s improvement comes from this one-minute video by 10 Questions Visualization. Not only does it highlight how clearer the new image is, but it zooms out to show the scale of the image in the sky, revealing the truly remarkable density of the new objects.
Of course, these images are just the first to be released, ushering in what should be decades of mind-blowing sights and discoveries. We can’t wait to see more of the universe through the powerful eyes of James Webb.