Euclid's first science images are breathtaking

This week’s big space news

Here’s a quick update on space news before we move onto the main event: The Euclid telescope’s first science photos!

• Boeing Starliner still hasn’t launched. NASA is currently evaluating how helium might affect various re-entry scenarios (apparently unrelated to the helium leak in the spacecraft that caused the most recent delay), so I’m not sure what’s going on here. There’s a press conference I’ll definitely tune in for tomorrow, but the launch date is now June 1.

• The Voyager 1 team is getting science results back from the spacecraft! This is a good sign that the spacecraft is well on its way to being operational again after a months-long communication issue made it seem like the spacecraft’s end was nigh.

• A recent discovery about dark energy may mean we have to re-evaluate our understanding of the universe. I dove into DESI’s first-year findings earlier this week with a full explanation of what dark energy is and what this might mean.

The first science photos from Euclid

We have the first science results from the Euclid space telescope, and five gorgeous images to look at!

Euclid is a space telescope from the European Space Agency designed to study the dark universe. It’s a survey telescope, and it’s going to create a map of the universe by observing over a third of the sky. The aim is to figure out how our universe has expanded and look more closely at the role of gravity and dark energy. 

If you missed my newsletter earlier this week at how new information about dark energy might change our understanding of the cosmos, that’s relevant here, but as a quick summary — scientists think dark energy is what powers the increasing expansion rate of our universe, while dark matter is what holds galaxies together. The two are basically unrelated, except for the fact that they’re both “dark” because they’re not directly observable.)

We saw the first images from Euclid last year, and they were absolutely stunning. 

But Euclid is designed to take larger pictures of the sky than JWST. The very cool thing about this observatory, though, is that it can take images that are both incredibly detailed and very wide (JWST has a narrower viewing area). We’ve never been able to take images that are this wide and detailed at the same time, so Euclid is pretty cool. This is also why Euclid being able to see as much as possible is important — and why the de-icing procedure, which I talked about previously, is so important.

The telescope is located at Lagrange Point 2, along with JWST, and is a million miles (or 1.5 million km) away from Earth. 

Okay, so let’s get to the results. Today, the ESA released five full-color images of the cosmos taken by the Euclid observatory, along with 10 papers from Euclid’s science data. 

A note on these images: I used lower-res photos for this newsletter, but I have a link to where you can take a look at the high-res photos on the ESA’s website for each picture because they are just that stunning.

Abell 2390, a galaxy cluster

First, this is Abell 2390, a galaxy cluster that’s about 2.7 billion light years away. There are more than 50,000 galaxies in this image, and what’s key about it is that it’s not stitched together. This is a single shot; for something with this wide a field of view, other telescopes would have to take multiple images and stitch them together.

Now, this is a closer in image, and you can really see here Euclid’s distinct diffraction spike pattern, which is distinct from JWST’s eight-pointed pattern. There’s also some round artifacts on some of the stars, and some of the brightest stars have double diffraction spikes.

It’s also clearer in this picture that what we’re looking at is a bunch of galaxies, versus stars in the sky. You can see a great example of gravitational lensing in the middle of this photo, which is when something like a galaxy cluster has so much mass it actually bends space and can magnify more distant objects (sort of like a bowling ball on a mattress). 

In this other image, the Euclid team artificially enhanced what’s called “intracluster light,” which is the white area in the middle of the photo. This is light emitted by stars that have been ripped from their host galaxies. 

This is an important image for Euclid because it’s galaxy clusters like this that the observatory will really be able to study dark matter — that’s what scientists think hold galaxy clusters together.

Messier 78, a star-forming region

The second photo is an incredible view of the Messier 78 star-forming region which is located about 1,000 light years away. While JWST is an infrared optimized telescope, taking photos in near- and mid-infrared, Euclid views the universe in visible light and near-infrared; this photo is a combination of both. 

This is a stellar nursery that’s surrounded by dust. Because this photo has near-infrared data, you can peer through the dust to the stars that are still enveloped by the dust. This image has revealed over 300,000 previously unknown objects. Euclid has a distinct color palette across its images: The hottest stars are a white blue, while ionized hydrogen gas looks blue. The dust and molecular gas looks red, while you can see distant redshifted galaxies in the background that are also red.

Again, I want to emphasize just how detailed this photo is. The top nebula here is NGC 2071. At the bottom of the image, you can see what’s called a dark nebula that’s producing lower mass stars.

Dark nebulae are interstellar clouds that contain a high concentration of dust. This means they absorb and scatter visible light, so they basically look black.

Studying areas like this will be important for Euclid because the detail here, and the fact that Euclid can capture objects that are just a few times the mass of Jupiter, can help scientists understand the mystery of “missing” matter — basically looking at the ratios of objects to understand if we can explain dark matter through objects like brown dwarfs and rogue planets that are difficult to detect.

NGC 6744, an archetype spiral galaxy

Okay, let’s move onto the next image: This galaxy is NGC 6744, and again, I’m like a broken record here, but look at this detail!!! This is outside of our galaxy cluster but in our galactic neighborhood at around 30 million light years away, and it’s representative of the kinds of galaxies that are forming stars in our area. 

You can see the structure of the galaxy here, but also zoom in and see “spurs” of gas on the arms of the galaxy. This image is so detailed that scientists will be able to count individual stars within it and use it to figure out the distribution of gas and dust in the galaxy.

You can also see the galaxy’s disrupted spiral arm at the top, where new stars are forming, and the neighboring dwarf galaxy on top. The interaction with that dwarf galaxy is what caused the disruption.

It’s so important to figure out how matter is distributed within galaxies to better understand how dark matter might hold galaxies together. Scientists can also figure out how this dust affects new star formation, as well as trace both new stars and older globular clusters thanks to this image.

Abell 2764, another galaxy cluster

Next we’ve got another galaxy cluster — Abell 2764, which is in the top right of this image!! 

Zooming in on that, we can see a bunch of galaxies, some edge on. This cluster is located about 1 billion light years away.

We can also see a lot in the surrounding area. Wider field of view images like this help scientists understand the structure of our galaxy, our galaxy cluster, and what surrounds it, as well as delivers insight into the early universe. Our galactic neighborhood is the Local Group, which has three large galaxies — our own, Andromeda, and Triangulum, as well as around 50 smaller and dwarf galaxies. 

We’re on the outskirts of a much larger galactic cluster called the Virgo Supercluster, which astronomers believe has a diameter of 110 million light years, containing at least 100 galaxy groups and galaxy clusters. And the Virgo Supercluster might be a part of an even larger supercluster of galaxies, which I feel like demonstrates why scientists are so interested in galaxy clusters. They’re everywhere, and they’re dominated by dark matter.

Speaking of our own galaxy, one very cool thing in this Abell 2764 photo is the very bright star towards the bottom of the image. This is actually within the Milky Way, and one thing this tells us is just how well Euclid handles overwhelming light sources. The fact that the telescope is able to still distinguish background galaxies behind this bright foreground star is amazing.

Dorado group, a group of galaxies

Okay, finally, let’s discuss the Dorado group of galaxies, which are located about 62 million light years away. These galaxies are evolving and merging at the same time, so it’s interesting to study the effect that galaxies can have on each other when they’re still in the process of forming. You can zoom in to see the interaction of these two galaxies.

Here’s a cool map of Euclid’s viewing area, and where each of these photos was taken. What’s remarkable about these photos is that they were taken across a single day — not each one took one day. The entire set of photos took one day to take. That’s remarkable, and I’m really looking forward to seeing what this observatory can do with longer exposure times.

If you’re wondering what the scale of these images are — it’s a good question. That information wasn’t included in the releases, but I think it’s really useful to understand how many light years across we’re looking at in these photos. I do have an inquiry in with their media office about this, and they confirmed they’re looking into it and will get back to me. I didn’t get the information in time for this newsletter but I will update the post on the website when I get it.