Have you seen the photos taken by the 1.4 billion euro telescope? Do you see that these photos now reveal the secrets of the intertwined past and present, space and time of the universe?
On November 7 this year, the Euclid Telescope at the L2 Lagrange point finally sent back the first batch of photos after its launch. These 5 photos not only demonstrate the powerful performance of the telescope, but also allow us to glimpse the beauty and mystery of the deep universe that we could not see in the past. Let us take a strange journey of exploring the universe through these unique photos!
What’s so great about the Euclidean telescope?
The Euclid Telescope, which was launched on July 1 this year, is tasked with observing the large-scale structure of the universe to study the distribution and properties of dark matter and dark energy in the universe, so that we can further understand the universe in which we live.
In July last year, James. The Webb Space Telescope has returned the first batch of photos after launch. Each photo is stunningly beautiful and allows us to view distant exoplanets, stars, nebulae and the early universe from a new perspective. At that time, we produced an episode to share with you the significance behind these photos. We also mentioned that after each telescope is calibrated, it will release a batch of “open lights” to convey the good news to the outside world that the telescope can operate smoothly, and at the same time let everyone understand the important missions of this new telescope. with tasks.
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And this time, the newly launched Euclid Telescope finally completed its calibration and returned illumination that was different from that of the Webb Telescope and looked at the universe from another perspective. Let us first understand the Euclidean telescope. Its observation band is from visible light to near-infrared, and its goal is to observe a wide range of cosmic objects at different distances. It is expected to establish a complete and clear 3D image of the universe during its 6-year service period. However, the Hubble Space Telescope, which has just been retired, is mainly responsible for research in the visible light band. The Webb Space Telescope, which officially started its mission last year, is a leader in the infrared band. So is there any breakthrough in the Euclid telescope? This telescope costing 1.4 billion euros certainly has its unique features. Its power lies in that it can obtain higher-resolution photos in a shorter time and capture a larger range of the universe at the same time. For example, the Hubble Space Telescope takes several days to observe celestial objects, but the Euclid Telescope can complete it in an hour, and the resolution is higher.
Euclid Space Telescope. picture/wikimedia
In fact, you can quickly understand by looking at their mission goals. Although Webb and Euclid are currently in the sky, some of their missions overlap. But Webb is more focused on finding exoplanets and observing the evolution of galaxies and star systems. Euclid, on the other hand, expanded his vision to the entire universe, hoping to understand the role of dark matter and dark energy in the entire universe. Therefore, compared with the Webb Space Telescope, which focuses on taking small-scale, high-resolution photos of celestial objects, the Euclid Telescope was originally designed to scan a larger area of the universe in a short period of time. Therefore, the Euclid Telescope has indeed become the best telescope to establish a 3D stereoscopic image of the universe. Regular large-scale scanning of the sky allows us to have a glimpse of the evolution of the universe over time.
So, let’s enjoy the first photos from the Euclid Telescope!
The first photos of the Euclid Telescope released!
The first photo is like scattering large and small pearls on the huge black cloth of the universe. It is an image of the Perseus galaxy cluster, 240 million light-years away from Earth.
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There are many galaxy clusters in the universe, and the Perseus Galaxy Cluster is one of them. It contains more than 1,000 galaxies and is one of the largest structures in the universe. In addition, this photo not only clearly captures galaxy clusters, but if you zoom in on the photo, you will also find that there are many galaxies in the background that were difficult to see in the past, with more than 100,000 galaxies, and the most distant one is even 10 billion. Light years. Why did the first batch of photos choose to capture galaxy clusters? Because studying galaxy clusters can help us understand the large-scale structure of the universe and further calculate the ratio of dark matter to dark energy.
The distribution of galaxies in the universe is actually uneven. There are many galaxies in some places and almost none in some areas. The distribution of celestial bodies in the entire universe looks like a giant web. But why is the large-scale structure of the universe network-like? Astronomers believe that after the Big Bang, the distribution of matter in the universe would have been slightly uneven. As the universe gradually cools, areas with higher density of gaseous matter will collapse due to the attraction of gravity. But because the temperature is very high, the huge pressure generated by the high temperature causes the gas mass to bounce back, just like squeezing a pressure ball. During the process of oscillating back and forth, the gas will be transmitted in all directions like sound waves, which is called baryon acoustic oscillations (BAO). In the end, the entire universe is like a pond under drizzle, forming a network structure of many intertwined ripples. The gas density is higher in the antinodes, turning into areas where galaxies are highly concentrated, which we call galaxy clusters. Elsewhere, the gas density is low and the number of galaxies formed is small, like holes in the universe.
According to calculations by cosmologists, in order to form large-scale structures in the universe such as galaxy clusters and the cosmic web, it is not enough to rely solely on the gravity provided by known matter. There may also be many substances that we do not understand yet. Among them, it is dark matter. This photo not only helps scientists study the large-scale structure of the universe, but also highlights one of the important tasks of the Euclid Telescope, which is to help scientists deeply understand the distribution and nature of dark matter.
The second photo is of the spiral galaxy IC342, which is only 11 million light-years away from the earth. It is considered a galaxy very close to the earth. However, because it is blocked by the bright disk of the Milky Way, it is very difficult to observe. The Euclid Telescope used near-infrared instruments to peer through dust and remove the light of many stars in the Milky Way, and finally produced this extremely high-resolution photo, demonstrating its ability to observe hidden galaxies.
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The size of this spiral galaxy in the sky is equivalent to the size of a full moon. To observe such a large area of the sky at once while maintaining ultra-high resolution is currently only possible with the Euclid telescope. Since spiral galaxy IC342 is very similar to the Milky Way, observing its evolution can help scientists understand the formation process of the Milky Way. In the future, the Euclid Telescope will also observe more hidden galaxies and distant celestial objects and draw their 3D distribution maps.
The third image is of the irregular galaxy NGC 6822. Although it is a galaxy like IC342 and the Milky Way, its shape is not spiral but irregular.
Through spectroscopic analysis, we know that the concentration of heavy elements in this galaxy is very low. Heavy elements are produced through the fusion of massive stellar nuclei. The low content of heavy elements indicates that the stars in the galaxy have just formed, that is, it is a very early and relatively young galaxy. Scientists believe that when galaxies first began to evolve in the early universe, most galaxies looked like this, with small masses and irregular shapes. Later, these small galaxies will attract other galaxies due to gravity, collide with each other, and merge into larger galaxies. They will gradually produce rotating structures and form massive spiral galaxies like the Milky Way. Therefore, observing these early galaxies can help scientists understand the formation process of galaxies.
In addition, the blue circular areas in the photo are globular star clusters. The stars in globular clusters are all produced from the same mass of gas. They are one of the earliest celestial bodies in the universe, and some are even older than the galaxy itself. Observing the motion of these globular star clusters can help us better understand the formation history of this galaxy.
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Globular star clusters are mostly distributed on the periphery of galaxies and orbit the galaxy at a very slow speed. It may take several years to observe their motion. So how do scientists know how these star clusters move? Everything we walk around leaves a mark, and one way of doing that is by observing the traces left by their interactions with the galaxies themselves. These details are revealed in the fourth image returned by the Euclid Telescope. The fourth image is of globular cluster NGC 6397, a globular cluster orbiting the Milky Way.
When a star cluster passes through a high-density area in a galaxy, such as a dark matter concentration area, a spiral arm, or a galaxy disk, the stars in the cluster will be attracted by gravity of different strengths, pushing the stars away from each other. This force is called a tidal force. As the name suggests, it is the same principle as the generation of tides. Since the sum of the gravity of the sun and the moon is different everywhere on the earth, the sea water is stretched and the tide rises in places with stronger gravity, and the tide ebbs in places with weaker gravity. In the same way, the gravitation of a globular star cluster is stronger on the side closer to the center of the galaxy and weaker on the side farther away from the galaxy. The globular cluster is thus stretched to form a tail composed of stars, called a tidal tail.
By observing tidal tails, we can understand the evolution of globular star clusters and even galaxies. If there is no tidal tail, it may also mean that there is a dark matter halo preventing the outer stars from escaping, which can help us further understand the distribution of dark matter in galaxies. But to understand the formation process of tidal tails, we must have movement data of each star in the cluster, which means we need to conduct large-scale, short-time, and high-precision observations at the same time. The advantages of the Euclid telescope can be fully utilized at this time. It can photograph the entire globular star cluster at once, and it only takes one hour to obtain this high-resolution photo, which can even see the very faint stars inside. Clearly. As long as you take a photo every once in a while, you can create an animation to understand the movement of the stars in the cluster.
Finally, we come to the last photo. It looks the most dreamy, like a piece of silk in the universe dotted with stars. It is the Horsehead Nebula, which is about 1,375 light-years away from Earth. It is also the area closest to us where new stars are forming. Above the nebula (outside the photo), there is a bright star: Sigma Orionis. The ultraviolet light radiated by this star excites the nebula behind the Horse’s Head, creating a bright, gauzy region. The dark nebula gas that makes up the Horse’s Head has only a slight amount of thermal radiation due to its relatively low temperature, creating a dimmer foreground and slightly obscuring the bright nebula behind it. The nebulae before and after are stacked up in layers, like a watercolor painting given to us by the universe. Furthermore, through the high-resolution photos taken by the Euclid Telescope, scientists can see more Jupiter-like stars, brown dwarfs, baby stars, etc., helping scientists understand the star formation process in the nebula.
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By the way, we mentioned when we introduced the Webb Telescope that these cosmic photos are usually not what we see with the naked eye in its visible light band. Instead, the result is obtained by selecting a specific wavelength and then performing color correction and even superimposing photos of different wavelength bands. In other words, if you choose different electromagnetic wave bands or adopt different color correction methods, the photos you get will have different flavors.
So if you feel dissatisfied with this pale and beautiful Horsehead Nebula, there is also this one, which specially enhances the red spectrum of hydrogen elements and the blue spectrum of oxygen elements, and becomes another kind of beauty with a bit of a weird filter that looks like an apocalypse. Photo, isn’t the atmosphere completely different from just now?
By the way, to me, even though it is a nebula photo, the photo color corrected by the Webb telescope still looks better. For example, as introduced before, the Carina Nebula is one of the illumination illuminated by the Webb Telescope. There is also the Pillars of Creation, which was originally the masterpiece of telescope pioneer Hubble and was later remade by Webb. It is even more amazing. The contrast and chroma are much higher, giving people a heroic feeling of looking up at the vast universe.
The Carina Nebula captured by the Webb Telescope. picture/wikimedia
Do we know more about the universe?
We still know too little about the universe. Currently, the known matter in the universe, including all atoms on the periodic table of elements, accounts for only 5% of the mass and energy of the universe. The rest is estimated to be dark matter and energy.
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But the mysteries of the universe are like a complex jigsaw puzzle. Each piece we put together gives us some clues as to what the surrounding puzzle pieces might be. With enough puzzles, we will one day know what the overall picture of the universe looks like. Star formation, galaxy evolution, dark matter, dark energy, etc. are all important pieces of the puzzle. Only by understanding them can we gradually learn the secrets of dark matter and dark energy.
For example, the gravity provided by dark matter plays an important role in the formation of galaxies. The cold dark matter model currently most accepted by the scientific community assumes that dark matter is composed of particles with very large masses that are attracted and gathered through gravity. into many small pieces, small pieces of dark matter then merge with each other into larger dark matter clumps. Clusters with enough mass can attract enough gas to form early galaxies, and then merge with each other to form larger spiral or elliptical galaxies. But through numerical simulations, scientists found that there were some problems with this model. Theoretically, there should be hundreds to thousands of small satellite galaxies orbiting a spiral galaxy as large as the Milky Way. But astronomers have actually only observed about ten small galaxies orbiting the Milky Way, which is known as the missing satellite problem.
Therefore, scientists have proposed more dark matter models, such as the warm dark matter model as opposed to cold dark matter, which can offset gravity through the pressure generated by thermal motion, making small dark matter clumps unstable, thereby explaining why small dark matter clumps become unstable. The number of galaxies is so small. In addition to thermal dark matter, there are numerous dark matter models. But to prove which model is correct, more observational data will be needed to compare with simulations of galaxy evolution to get the answer.
However, after seeing the first batch of photos sent back by the Euclid Telescope and understanding the significance of them, you can fully feel that we are one step closer to solving this mystery. It’s not over yet. The Nancy Grace Roman Space Telescope, which is expected to be launched in 2027, has the same important mission as the Euclid Telescope to study dark energy and dark matter. Together, the two telescopes will observe a large range of the universe, one from visible light and the other from infrared bands, hoping to bring valuable data to scientists and solve this mystery that has been lingering for decades.
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Finally, let me ask you, among these photos, which one is your favorite?
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