President Joe Biden’s unveiling of this first image wasn’t exactly sensational, but the image itself? Majestic. Known as “Webb’s First Deep Field,” it gives astronomers a look at the galaxy cluster SMACS 0723. JWST’s First Deep Field was revealed on July 11. NASA, ESA, CSA and STScI What you’re looking at is a tiny slice of the Southern Hemisphere sky — the equivalent of a grain of sand held up to the heavens — yet filled with thousands of galaxies, from spiral and elliptical to mere pinpricks of light just a few pixels wide. And thanks to a phenomenon known as gravitational lensing, it gives us the deepest and oldest view of the Universe to date — as well as concrete proof of Albert Einstein’s general relativity. That’s a lot to live up to, right? Well, even though the images released on Tuesday don’t reach that far back in space and time, they are undeniably deep, equal to the First Deep Field in beauty and finely woven with exquisite cosmic detail. Three important images make up the first color set of the JWST. Two focus on nebulae, vast clouds of dust and gas in which stars are sometimes born, and the other analyzes a region known as Stefan’s Quintet, a terrifying corner of the universe where five galaxies are locked in an ultimately deadly dance. Then there’s the spectral data of WASP-96 b — a really hot, giant, gaseous exoplanet — revealing the composition of its atmosphere in unprecedented detail. This is not an image as you might expect, but arguably something even more valuable. It’s a spectral data set that helps us understand not what a space object looks like aesthetically, but rather what it would be like to stand on it. And, as they say, the book is often better than the movie. Let’s break each one down and explain why JWST’s second batch of cosmic goodies is just as ground-breaking as its first look.
The nebulae
Nebulae are huge clouds of dust and gas that exist at either end of a star’s life. Some host newly formed baby stars, while others are created from their explosive deaths. But in both cases, nebulae are responsible for some of the most stunning visuals we have of our world — and through the lens of JWST, the most powerful infrared imager we’ve ever worked with, their wonder only gets better. You can read exactly how JWST’s infrared imaging works here, but the basic principle is that it can access light — emitted around the world by stars, galaxies and other bright objects — that is stuck in an area of electromagnetic spectrum invisible to our eyes. And more specifically in nebulae, this “hidden” light, so to speak, happens to be the main kind that shoots through their dust clouds from what’s inside. This means that our pupils, even massive telescopes like the Hubble Space Telescope, cannot penetrate the nebulous curtains of gas. They are veils that usually obscure our view of the flashy features within — that is, stars that are just rekindling or those that are in the process of dying. JWST’s instruments, however, easily bypass them via infrared imaging to check what’s going on behind the scenes. In addition, NASA’s next-generation scope offers much (much) better resolution than a telescope like Hubble — in fact, capturing the appearance of the inner nebula as well as the outer structure with a sophisticated clarity novel to the human eye. Now that we know what we’re going to see, let’s get into it. For the first scientific discoveries of the nebula, JWST focused on two separate stardust clouds: the Carina Nebula, located about 8,500 light-years from Earth, and the Eight Burst Nebula, which is much closer at about 2,000 light-years away. Starting off strong, here it is: the Eight Burst Nebula. It is also known as the Southern Ring Nebula. On the left is a version of the Southern Ring Nebula taken by JWST’s Nircam and on the right, by MIRI. NASA “This is a planetary nebula,” said NASA astronomer Carl Gordon. “It is caused by a dying star that has shed a large fraction of its mass in successive waves.” These shock waves are clearly visible in the image, they are the lake-like ripples that float around the biological cell-like center. On the left, you’ll see them a little more clearly. That’s because this side is a version of the nebular image taken by JWST’s Near-Infrared Camera, or Nircam. It is often considered the holy grail of the telescope because it leads to finding pieces of the unseen universe. In this case, Nircam helps visualize the layers of light that connect to make up this complex system. Like a mixed media painting, it offers enough texture to highlight different aspects of the Southern Ring, including those shock waves. And on the right is a version of the image drawn by JWST’s Mid-Infrared Instrument, or MIRI. Like its name, MIRI’s specialty is catching light from the mid-infrared region of the electromagnetic spectrum. Thanks to MIRI, we also have a fascinating easter egg in this photo. Right in the center of the cosmic eye, there are clearly two stars. Next to the brighter one, we can see the dying nebula — the dot that appears redder on the left. This twin star was thought to have existed in the past… dancing around each other in an intergalactic waltz. But we had never seen both of them together before. This is the first time. MIRI captured both stars present in this nebula for the first time. Photo by Monisha Ravisetti / NASA According to NASA, the brighter star will likely eject its own planetary nebula in the future — but until then, it will continue to influence the appearance of the nebula, giving us the vivid spectacle we see today. “As the pair continue to orbit each other,” NASA says, they “stir the pot” of gas and dust, causing asymmetric patterns. Also, in this right image, if you take a look at the upper left, you’ll see a mysterious blue line that appears to have been thrown out of the nebula. This little line has its own long history. See that blue streak? Photo by Monisha Ravisetti / NASA “I made a bet that said, ‘It’s part of the nebula,’” Gordon said. “I lost the bet, because then we looked more closely at both the Nircam and MIRI images, and it’s clearly a cutting edge galaxy.” Yes, there is an entire galaxy far, far away hidden in this image. JWST has a few tricks up its sleeve. Next up is the Carina Nebula — once again, courtesy of JWST’s Nircam and MIRI. NASA “Honestly, it took me a while to figure out what to call this image,” said NASA astrophysicist Amber Straughn. “There’s so much going on here. It’s so beautiful.” This stunning image is technically the edge of a giant cavity within a nebula called NGC 3324, known as the Carina Nebula. It has an incredible wealth of emerging stellar nurseries, cosmic rocks and individual stars that call this nebula home. Until now, all these cosmic glimmers and details have been completely hidden from our view by the dense dust and gas surrounding them — but, remember, JWST’s infrared cameras can literally pierce this veil of intergalactic secrets and get access to valuable attractions within. Decoding this image could well shed light on how stars form, what kind of star-forming material goes into that formation, and even dissect the mechanism of violent, stellar winds that affect the surrounding space. And if you’re curious about all those hills, valleys and peaks? So do NASA scientists. They are somewhat of an unsolved puzzle. Or as Straughn puts it, “we’re seeing examples of structures that, frankly, we don’t even know what they are.” What we do know, however, is that JWST just gave us a groundbreaking view of an alien world. An exoplanet.
WASP-96 b
The hot, gas giant exoplanet WASP-96 b is a scientific curiosity. Its parent star, WASP-96, is about 1,120 light-years from Earth, making it the closest object in Webb’s first batch of images. Here is.
NASA
Okay, so while this image isn’t what you’d normally think of when you’re hoping for a planetary portrait, it’s incredibly important to the field of astronomy. What you’re seeing is direct spectral data of an exoplanet in a solar system beyond our own. While we don’t have a view of the planet hanging in space next to its star, this “spectrum” leads us to the ingredients that make up this alien world. What the astronomers found is impressive. JWST’s spectral analysis of WASP-96 b shows a telltale signature of water vapor in the planet’s atmosphere, as well as evidence of clouds and haze, which are tiny solid particles that act like pseudoclouds. And yes, I said water. But before you get too excited about packing up to move to WASP-96 b, a world laced with H2O, note that this exoplanet is closer to its star than Mercury is to the sun. This means that it is very hot and all its water is not liquid. Oh, and it orbits this star every three and a half Earth days. This is probably (definitely) not habitable for us Earthlings. A hypothetical depiction of WASP-96b from NASA’s exoplanet catalog. Photo by Monisha Ravisetti / NASA Regardless, it’s an interesting find because while astronomers have, so far, identified more than 5,000 worlds outside our solar system — and have studied many of them with Hubble and other space telescopes — WASP-96 b always stood out for its potentially unusual atmosphere. But until now, we haven’t had a good look at this planetary shield, making WASP-96 ba a hot topic for discussion. “Most nearby exoplanets studied with Hubble have flat, white spectra, which is seen as evidence that they are very nebulous,” said Benjamin Pope, a planetary scientist at the University…
