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NASA’s James Webb Space Telescope is often called a “time machine.”
On Tuesday, the $10 billion telescope earned that nickname after NASA released five images of the universe as it appeared more than 13 billion years ago—within 700 million years of the Big Bang. The pictures deliver the deepest, sharpest, and most telling look yet into how galaxies merge, where stars are formed, the composition of space objects, and much more.
The Webb is 100 times faster and more powerful than its predecessor, the Hubble Space Telescope—and that’s because of tech advancements over the past three decades, Stefanie Milam, a deputy project scientist for planetary science on the James Webb Space Telescope team, told us. Hubble was primarily a visible-light telescope, whereas Webb uses infrared spectrometers and cameras, plus large mirrors, allowing it to deliver higher-resolution images than ever before. The telescope’s multi-shutter array allows it to collect information on up to 100 different galaxies at once, compared to Hubble’s one-at-a-time operation.
Let’s take a tour through the telescope’s first five images and what they can tell us about the universe.
‘Distortions of time’
Even though this snapshot covers just one grain of sand’s worth of sky, it contains thousands of galaxies—and if you were to zoom in, you’d see increasing detail for each galaxy, even the ones that look like faraway specks.
“The most notable thing about this image are the smeared-out galaxies—the ones that look like Dali clocks kind of drooping around,” Milam said.
The reason for these “distortions of time”? Each galaxy is so large in mass that it’s acting as a lens of its own, distorting the light of further galaxies beyond it. With Webb, scientists can take the spectra (think: fact sheet) of each galaxy to find out its composition, temperature, velocity, direction, age, and more.
In these images of a planetary nebula about 2,500 light-years away, Webb captured an ancient star at the end of its life, during its White Dwarf phase, Milam told us. The rings around it are made of gas and dust that blew off the star during its Red Giant phase and are now being lit up by the nebula’s hot, bright center.
This image offers a never-before-seen level of detail into a dying star’s temperature, the speed at which the surrounding dust is traveling, and the composition of that material (the gold material is molecular hydrogen, the red is sulfur, and so on). That’s valuable, in part, because the same process will one day happen with our own sun.
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“This is the first phase of the recycling of stardust, and it’s where new elements, new molecules, are being found and preserved in some manner, either as the dust that’s coming off or the gas,” Milam said. “All that material will eventually make another star, or another galaxy—and that’s the recycling nature of stellar life.”
In this image of Stephan’s Quintet—a group of galaxies in the Pegasus constellation, roughly 400 million light-years away—Webb captured an early instance of galaxies merging due to gravitational pull. It’s the telescope’s largest image yet, “covering about one-fifth of the moon’s diameter,” according to NASA.
When galaxies merge, Milam said, it’s a “whole disruptive process—it’s destroying material because of the energetics of the merging material, but it’s also embedding new star birth and other things forming and going on within these galaxies as they become one giant mega-galaxy.”
The biggest takeaway here, she added, can be seen in the center of the galaxy on top: an active galactic nucleus, complete with a black hole. Webb can’t capture the black hole itself, but it did capture how it affects nearby material—notice the reddish gas being sucked into the center, for example.
Behold the “Cosmic Cliffs” in the Carina Nebula, roughly 7,500 light-years away. Previously, Hubble captured the entire nebula, Milam told us. With Webb, scientists created a high-resolution snapshot of just one of the nebula’s star-formation bubbles.
“With these longer wavelengths, we basically have night-vision goggles,” Milam said. “At visible wavelengths, [a telescope] can’t see within clouds and dust, the same way our eyes can’t.”
While Hubble couldn’t penetrate clouds of gas or dust, Webb can—“and that’s really an interesting area because that’s where new stars and planets are being formed,” Milam added.
The top section of the image shows stars that have already matured enough to begin forming their planetary systems, and the lower section offers a window into countless still-forming stars. But scientists still have many questions about the intricacies of star birth, like which conditions contribute to small versus large stars.
“Having the capability of seeing into the star-forming region already tells us we don’t know anything—or what we do know is very limited,” Milam said.
Update: This piece has been updated to clarify the time frame captured by the initial James Webb Space Telescope photos. We initially wrote: ~13.5 billion years ago—or 300 million years after the Big Bang. We've now updated the piece to say more than 13 billion years ago—within 700 million years of the Big Bang.