In Einstein’s general relativity, matter and energy bend spacetime.
An animated look at how space-time responds when mass moves through it helps illustrate how qualitatively it is not just a piece of cloth. Instead, all three-dimensional space itself becomes curved due to the existence and properties of matter and energy within the universe. Multiple masses in orbit around each other will emit gravitational waves, while any light passing through a region containing this warped spacetime will be bent, distorted and perhaps amplified by the effects of curved space.
If we gathered enough mass in one place, space would be severely distorted.
In this image, a massive cluster of galaxies at the center gives rise to several powerful lensing features. Background galaxies have light that is bent, stretched and distorted into rings and arcs, where it is also amplified by lensing. This gravitational lensing system is complex, but useful for learning more about Einstein’s relativity in action.
When light passes through that distorted region, bending and magnification ensues.
A distant background galaxy is so sharply imaged through the overlapping cluster filled with galaxies that three independent images of the background galaxy can be seen, with dramatically different light travel times. In theory, gravitational lensing could reveal much fainter galaxies than would be seen without such a lens, but all gravitational lenses only occupy a very narrow range of locations in the sky, as they are placed around individual mass sources.
It behaves similarly to an optical lens, but is powered by gravity: gravitational lensing.
One of the most dramatic features found in the El Gordo field, as seen with the eyes of the James Webb Space Telescope, is the most distant red giant star ever discovered: Quyllur, the Quechua term for star. It is the first red giant star to be discovered more than a billion light-years away, and in fact it is more than 10 billion light-years away. It was only visible due to the unique capabilities of the James Webb Space Telescope combined with the magnification of El Gordo’s gravitational lensing.
When the observer, lens, and background objects are all aligned, Show amazing features.
This illustration of gravitational lensing shows how background galaxies – or any light path – are distorted by the presence of intervening mass, but it also shows how space itself is curved and distorted by the presence of the foreground mass itself. When multiple background objects are aligned with the same foreground lens, multiple sets of multiple images can be seen by a properly aligned observer, or even an “Einstein ring” in the case of perfect alignment. If a transient event, such as a supernova, occurs in the background galaxy, it will appear with time delays in the different images.
Arcs, multiple images, and even entire episodes become possible.
This side-by-side view of galaxy cluster SMACS 0723 shows MIRI (left) and NIRCam (right) views of this region from the James Webb Space Telescope. Note that although there is a bright galaxy cluster in the center of the image, the more interesting objects are gravitationally distorted and amplified by the cluster itself, and are located much further away than the cluster itself.
Often, galaxy clusters make the best gravitational lenses, as they have very large masses.
The triple lensed galaxy shown here is known as “The Hook”, due to its unique appearance formed by foreground gravitational lensing. While the entire foreground cluster, El Gordo, depicts the background galaxy, it is the prominent double galaxy in the foreground cluster that provides “Fishhook” with its striking appearance.
But massive compact galaxies could theoretically act as gravitational lenses, too.
This object is not a single ring galaxy, but rather two galaxies at very different distances from each other: a nearby red galaxy and a more distant blue galaxy that is gravitationally influenced by the mass of the foreground galaxy. These objects simply lie on the same line of sight, with the background galaxy’s light distorted, stretched and amplified by gravity by the foreground galaxy. The result is a near-perfect ring, which would be known as an Einstein ring if it were a perfect 360-degree circle. Although lensing is more common than clusters of galaxies, individual galaxies can do so if they are compact enough and if the alignment is right.
Such galaxies are rare todayBut massive, compact galaxies were common 10 to 12 billion years ago.
Taking us far beyond the limits of any previous observatory, including all ground-based telescopes on Earth plus Hubble, NASA’s James Webb Space Telescope has shown us the most distant galaxies ever discovered in the universe. If we map the 3D positions of observed and measured galaxies well enough, we can create a visual representation of the universe, and CEERS data from JWST enables us to do that here. At greater distances, compact galaxies are more common; At closer distances, more diffuse galaxies are the norm.
Observed by the James Webb Space Telescope, it is a massive, compact, distant galaxy It has been found to behave like a gravitational lens.
This gravitational lensing system from the COSMOS-Web field consists of a massive, compact galaxy located approximately 17 billion light-years away, and a more distant galaxy 21 billion light-years away whose light is stretched into a ring-like shape. The decomposition of the two components is shown below.
The lens itself is 17 billion light-years away: another 2.3 billion light-years away From the previous record holder.
This image shows James Webb Space Telescope data in five NIRCam filters at different wavelengths (top) of the gravitational lens and the lensed galaxy behind it together. Below, the light is split to show the front lens (left) and rear ring (right) separated into their respective components.
Another 4 billion light-years beyond the lens is a background galaxy, imaged with a lens-perfect shape In Einstein’s ring.
The same region of space imaged by the James Webb Space Telescope was previously imaged by Spitzer at long wavelengths (24 microns). The difference in resolution between the two observatories, combined with discrepancies in signal-to-noise, shows just how superior the James Webb Space Telescope (JWST) is to its predecessor in the infrared field.
The ring-shaped light reveals the mass of the lens: 650 billion suns, concentrated within just a few thousand light-years.
Once the most distant lensed galaxy was identified in the James Webb Space Telescope data, archival Hubble data were examined, where evidence of a ring and foreground lensing were detected in the data, respectively, at 814 nm and 1.6 microns.
Multiple imaged features within the ring may be resolved within the background galaxy.
By examining only a subset of the light from the James Webb Space Telescope, the ring can be separated from the front lens, where several key features (such as the red glow and bright star-forming regions) are highlighted and appear several times. With further analysis and future data, individual features in the background, and the lens system, can be fully reconstructed.
With the lensing zoom and capabilities of the James Webb Space Telescope combined, the universe increasingly comes into focus.
This wide-field view, centered around the farthest gravitational lens ever discovered, shows an area larger than the COSMOS-Web field. The Einstein ring is clear evidence of the existence of gravitational lensing.
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