In July 2022, it was released The James Webb Space Telescope (JWST) – The most powerful human telescope ever put into space – He submitted his first photo, an image of the deep field containing thousands of galaxies, many of which look like they did in the early universe. What many people didn’t expect was how some of these twisted and strange galaxies would appear.
The Salvador Dali Galaxy that looks like melted candy is not representative of what these objects look like in space; This is an illusion in the JWST image. Other amazing aspects of JWST’s images, such as One taken from the RX J2129 supercluster, Multiple galaxies appear at multiple points in the same image. Again, this is an illusion. These galaxies do not actually have doppelgängers.
How is this possible? The two different aspects of this JWST image are the result of the same phenomenon, called gravitational lensing. Predicted for the first time more than 100 years ago by Albert EinsteinGravitational lensing has been an important tool for astronomers through workmagnifying glass. These distorted and repeating galaxies are examples of objects that have gravitational lensing.
Related: James Webb Space Telescope Images: 12 stunning views of our universe (gallery)
What is a gravitational lens?
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Gravitational lensing is a phenomenon predicted by Einstein’s theory General relativitywhich shows that gravity It arises from the influence of objects with mass on the fabric of space and time, united as a single unit called spacetime.
Think of an elastic rubber board with balls of different masses placed on it. The greater the mass of the ball, the more it wraps around the rubber sheet. The same is true for objects with large masses found in the fabric of space-time: the greater the mass, the more space-time objects are warped, by things like galaxy and galaxy clusters that cause severe space-time distortions. This effect becomes especially interesting when light from background objects, such as stars or galaxies, passes through this bend.
Related: The James Webb Space Telescope observes the cosmic seahorse through gravitational lensing (photo)
Light travels in straight lines, regardless of whether the space through which it travels is distorted. The bending of space with mass causes light coming from distant sources to “bend”. As a result, when the light hits Landit makes background objects appear to be in a different place in the sky.
In extreme warping situations, when the object between Earth and a background source is massive, light takes different paths around the object, all curving to varying degrees. This changes the length of the path that light takes to reach us to varying degrees, and thus the time of arrival. This means that the lensed object can appear at multiple points in a single exposure. This can give rise to some interesting shapes, such as a cross, or, in the case of lenses with perfect symmetry, a ring of light called an “Einstein ring”, all made up of repeated iterations of the same object.
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Galaxy clusters have a “messy” shape, with the clusters not having a centralized distribution, so that when they act as intermediary objects or lensing, the lensing is imperfect. According to the European Space Agency (Opens in a new tab). This causes lensed objects to appear distorted as arcs around lenticular galaxy clusters, as seen in the JWST inner field images.
However, these lenticular objects are more than just a visual curiosity. Gravitational lensing can benefit astronomers in a number of ways.
Gravity lensing doesn’t just distort the light from background objects; It can actually amplify this light, thus enhancing the very dim glow of very distant objects, such as early galaxies. As a result, gravitational lensing was critical to JWST’s early universe investigations.
Additionally, the pattern that a lenticular object makes when light passes through it can reveal a lot about that object. NASA explains (Opens in a new tab). For example, gravitational lensing can reveal how matter is distributed in galaxy clusters and galaxies.
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Additional resources
Explore gravitational lensing in more detail with this Resources from NASA (Opens in a new tab). The Fermi National Accelerator Laboratory has also produced a useful video demonstration of gravitational lensing Salaran YouTube Fermilab (Opens in a new tab).
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Kelly, b. (2023, 28 Februari). Triple vision. ESA/Webb, NASA, dan CSA. (Opens in a new tab)
NASA. (2022, 30 September). gravity lens. Hubble site. (Opens in a new tab)
