While humanity is advancing at full speed to explore the unknowns in the depths of space, an important sharing that will go down in space history was made last night. NASA shared with the world the first color image taken by the James Webb Space Telescope, which it sent into space after years of delay.
In that photograph belonging to the SMACS 0723 cluster, where many galaxies can be observed at the same time, there were stars and galaxies in every area that the eye could see. Reminding the infinity of the universe and our childhood, this photograph also had a phenomenon that attracted the attention of many: Some galaxies, especially in the middle of the photograph, seemed crooked as if they had entered an invisible gravitational field. So what was the reason for this?
Why do galaxies appear bent?
The trapezoidal appearance of galaxies in the area marked in the above image taken by the James Webb Space Telescope is due to a condition called ‘gravitational lensing’. Let’s take a closer look at this situation, which is one of the predictions of Einstein’s general theory of relativity and has been proven many times with photographs.
Every object in space has a mass, and this mass of objects can bend the space and time around it. Due to this bending, the actual position of any observed object, which you can see in the image below, may differ depending on its position reflected in our eyes and telescope lenses. The first proof of this was provided by Arthur Eddington and Frank Watson Dyson during the 1919 Solar Eclipse, when they observed that the light coming from stars passing very close to the Sun is bent.
According to the general theory of relativity, light also follows these curves that occur in space-time. Therefore, when light passes around a massive object, it is bent due to the bending of space-time by the effect of that object. The travel of light in the bending space may also give humanity the chance to observe celestial bodies that are hidden behind other objects and that are far away. An example of this situation can be explained with the following image:
In addition, this situation can cause other structures behind the massive structures to appear more than once. For example, in the picture below, a quasar, which is actually behind a giant galaxy, can appear as separate celestial bodies in four different places due to the bending of the light it emits.
Therefore, the new image, which is the clearest image of the distant universe ever taken, clearly shows the effect of gravitational lensing. Some of the galaxies that we would not be able to see without this effect have the potential to be one of the oldest galaxies. Of course, we must also take into account the fact that we see these galaxies billions of years ago.
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