You probably heard earlier today that the first images from the James Webb Space Telescope were released to the public. Even the Google banner heralded the release of these images, so you know it’s big news. In short, the images are stunning! The details and colors are remarkable. I’ve included a copy of all five images in this post. If you’re reading this, you probably appreciate their sheer beauty even without knowing what you’re looking at. So, I thought it would be nice to dig a little deeper and uncover some of the science illustrated in these images. Besides, I haven’t created any of my own images to share lately…why not talk about someone else’s? Over the next five posts, I’ll describe each image one by one as best as I understand them. Hopefully, this will help you understand them better too. Let’s go!
Before I begin, note that the images I’ve included here are all downsized to meet the demands of social media. That’s bad news because you can’t see the exquisite details, which is what makes these images special. The good news, however, is that you can download high-resolution versions of the images (and many, many more) from the NASA/STSci website. Just Google it.
The first image is creatively called “Webb’s First Deep Field.” It has some amazing things going on. The bright center contains a cluster of closely spaced galaxies that bend the fabric of space to create a gravitational lens. What?? A gravitational lens? Sounds more like science fiction than science, but this phenomenon is predicted by Einstein’s theory of general relativity. The gravitational lens in the image causes distant galaxies on the other side of the lens to be magnified and distorted from our viewpoint. It’s like stacking two telescopes together: one of which uses the reflective surfaces of Webb and the other gravity from the distant galaxy cluster. How cool is that?? By the way, this is the same effect you see if you look through the bottom of a glass at a bright light source. Much less cool though. The arcs near the center of the image show the distorted galaxies. To be clear, these misshaped galaxies appear that way due to the gravitational lens. Without the gravitational lens, the stretched galaxies would appear as normal elliptical galaxies.
Outside the view of the gravitational lens, Webb’s first image reveals other fascinating details. Using instruments that measure the wavelength of light, JWST shows that elements found here on Earth are also present in these distant galaxies. For example, we’ve all heard of neon lights. They’re called that because they utilize the element neon to create light from electricity. Webb shows that neon is also present in galaxies billions of light years away. I wonder if distant cultures make beer signs the same way we do with neon?
Webb’s first image also reveals galaxies more than 13 billion light years from us. These are the most distant galaxies ever viewed. Since the Universe is about 13.8 billion light years old, these galaxies could represent the first galaxies that formed after the Big Bang. Pretty cool.
And if all that is not exciting enough, there is even more to Webb’s first image. The bright six-sided starbursts are stars within our own Milky Way galaxy. These stars are relatively nearby. Ho hum. But every other dot of light is from a galaxy outside our Milky Way. There are probably 1000s of galaxies in this frame if you look closely. And each of those galaxies contains billions of stars just like those in our Milky Way galaxy. To put this in perspective, Webb’s first image is a tiny patch of sky equivalent to the size of a grain of sand held on your fingertip at arm’s length. That means the number of galaxies and stars across the entire sky is beyond comprehension. We simply cannot comprehend numbers that big.
OK, that’s all I know about Webb’s first image. That’s a lot for just one image, but it is just the tip of the cosmic iceberg. There will be more to come. I’ll talk about the other images from JWST in my next post. I can’t wait to talk about how Webb uses spectroscopy to analyze the molecular composition of the atmospheres of distant planets outside our solar system. Yikes.