I was going to write today about the launch of Artemis on its way to the moon, as America renews its glorious leadership in the exploration of earth’s closest neighbor. Then, Boeing’s famously troubled rocket horked up a hairball on the launch pad.
Oh well, maybe next week.
At any rate, I decided this would be an opportune time to catch up instead with all the great things the James Webb Space Telescope has been doing. The brilliant successor to our revered Hubble Telescope, Webb launched all the way back on Christmas day. Can it really be so long already? Unfortunately, since this blog was, er, in cryostasis at that time, it was silent on one of the great technological feats of this or any other century. Let’s make amends, shall we?
On the Webb
As an informed and engaged member of the newsgathering public, you will no doubt have seen the now-famous photo of Jupiter at the top of this article. Captured a few days ago by JWST, the false color composite image is both elegant and informative. We see the auroras crackling at north and south poles, the hint of wispy rings, Olympian cloud formations twisted by powerful winds, and extreme conditions of temperature and pressure — all in a picture gorgeous enough for Jupiter to use as a graduation photo.
But that’s only a small bit of what JWST has been up to since that breathless, flawless launch nine months ago. Because it takes a substantial amount of time for NASA to amass the telescope’s data and process it into finished images, only a tiny portion of the reams of data captured so far have been rendered into pictures for public release. But those that have are spectacular, including these:
My favorite so far, just for sheer sex appeal, is the Carina Nebula (top). A stellar nursery in our own galaxy, Carina is a colossal cloud of dust about 7000 light years from earth. Pulled together by gravity, the dust congeals over millions of years into clumps that heat up and develop into new stars. While the nebula has already been captured in a famous Hubble photo, this new image is far richer in detail and articulation.
The second image is the Cartwheel Galaxy, a phenomenon with a very unusual configuration. Astrophysicists hypothesize that it may once have been a conventional spiral galaxy, but another galaxy came along and smacked into it side-on — right through the bullseye, like a stone into the center of a pond — causing the material inside to ripple outward and form the ring at the outer edge. Thanks to JWST, we can now tease out the various elements that make up the galaxy: the central “eye”; the outer ring; the dust patterns thrown by the great collision; and even what appear to be new spiral arms beginning to form. (One of the new mysteries created by this image is how those arms could be forming so soon — cosmically speaking — after the collision.)
The last image is of Stephan’s Quintet, a fascinating grouping of galaxies of which four appear to be moving to collide with one another. Although Stephan’s Quintet has been studied since the Nineteenth Century, the James Webb image uncovers many aspects of the cluster for the very first time — such as the dust cloud distribution in NGC 7320, the galaxy to the left; details of the massive shock wave, the red arc in the middle of the image, caused by the collision of the galaxy directly below it (NGC 7318) with the one above (NGC 7319); and even individual supernovae in the galaxies.
Understand that these phenomena wouldn’t look like this if you were floating close enough to see them (and, y’know, didn’t die immediately in the icy vacuum of space). The images are composites of data from various wavelengths, most of which are not visible to the naked eye. When the data are processed, artificial colors are assigned to image captures of different wavelengths — oranges and reds to longer wavelengths, and blues to shorter ones — and then the layers are superimposed. One of the most useful aspects of the Webb telescope is that it captures data in multiple infrared wavelengths — allowing us not only to see through dust clouds to the stars and galaxies beyond, but also to see the farthest galaxies, which are moving away from us so fast that their light waves are stretched far into the infrared spectrum.
Moreover, especially in the case of something like the Cartwheel Galaxy, what you’re seeing is the state of the phenomenon not as it exists today, but as it was hundreds of millions of years ago. And that’s awesomely useful, because it allows us to see the state of a piece of the universe as it was that much closer to the Big Bang.
Maybe the most remarkable thing about James Webb at this point is that, for all the hype before its launch — and my God, was there ever a science instrument more hyped than JWST? — it has actually performed better than anyone seems to have anticipated. Planetary astronomer Imke de Pater at Berkeley has said “We hadn’t really expected it to be this good, to be honest.” CNN’s aerospace guy Miles O’Brien, viewing the Carina image with misty eyes, simply described himself as “verklempt“. Reactions from other experts have been similar.
Leaving these exciting images aside, though, the very best thing about JWST is its potential to help us understand aspects of the universe that we’ve never before had the wherewithal to find out. As a small example, the telescope has already shown that disk galaxies were likely more populous, and smaller, in the early universe than was previously known; because now we can simply see them much more clearly than we could with Hubble. Much more importantly, in time the new telescope may help us to unravel two of the very deepest and most intractable enigmas of the cosmos: dark matter and dark energy.
I don’t know about you, but I can’t wait.
Ronald Crittenden 