Let’s explore Webb’s first images

A couple of days ago, the first images of the James Webb Space Telescope were published. Have you seen Webb’s first images already? They are astonishing! Let’s take a closer look at two of them and try to understand, what we are seeing in the images.

Deepest and sharpest infrared image of the distant universe

Let’s start with the first image unveiled by President Joe Biden during an event on 11 July 2022. Here it is:

It is showing the galaxy cluster SMACS 0723 as it appeared 4.6 billion years ago. You wonder why I wrote 4.6 billion years ago? Because it took the light 4.6 billion years to get us. So, what we are seeing is how it looked back then.
By the way, this also happens with light from our Sun. It takes the light about 8 minutes to get from the Sun to Earth. So by the time we see the light from the Sun, it is already 8 minutes old. Therefore, when we look at our Sun, we see it how it was 8 minutes ago.

Anyway, let’s get back to the picture. See those bright points with spikes in the foreground? Those are stars with diffraction spikes, which form because of how the telescope itself is constructed. Behind them, we have a massive cluster of galaxies. And way back in the background, we have oddly stretched mostly reddish objects. Those are also galaxies, but way older than the ones in front. But why are they so stretched?

That happens, because the cluster of galaxies in front is so massive, that it acts as a gravitational lens. It’s like a magnifying glass. In this case, it enables us to see galaxies way behind the cluster in front. And as “way behind” also means way more back in time, those are images of some of the oldest galaxies so far. Also including some which existed, when the universe was less than a billion years old.

This is a zoomed in part of the image above. See the two stretched reddish galaxies? This is another effect of the gravitational lens. It actually is only one galaxy, that appears twice in this view. Scientists confirmed this recently by comparing the spectrums of both using an image taken by the Hubble Space Telescope. And again confirmed it with Webb.

The cosmic cliffs

Let’s take a look at one more image. The one at the top of the post. This is called the cosmic cliffs of the Carina Nebula. It is in a star-forming region called NGC 3324 in the Carina Nebula. In the lower part of the image, you see dust-clouds. On top, you see a region with newly formed stars. Radiation from these stars is interacting with the border of the nebula, changing its shape.

In this new image, we can see a lot more stars in the dust-cloud itself. This is because Webb works with infrared light and can therefore see through the dust. This will help scientist to better understand how stars are formed in the future. And aside from that, the picture is just pretty.

More to come

Those are only the very first pictures of the James Webb Space Telescope (short JWST or Webb). Like with Hubble, we’ll see a lot more images in the future. If you want to know more about the images, take a look at the links below or read my post about the orbit Webb is using.

Credit for all images in this post: NASA, ESA, CSA, and STScI

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