The huge galaxy cluster in the center of this image includes so much dark matter mass that its gravity bends the light of more remote objects. This suggests that for really far-off galaxies in the background, the clusters gravitational field acts as a sort of magnifying glass, bending and focusing the far-off objects light towards Hubble. These gravitational lenses are one tool astronomers can utilize to extend Hubbles vision beyond what it would usually can observing. This way some of the really first galaxies in the Universe can be studied by astronomers. The lensing result can also be utilized to identify the distribution of matter– both dark and normal matter– within the cluster. Credit: NASA, ESA, J. Richard (CRAL) and J.-P. Kneib (LAM), Acknowledgment: Marc Postman (STScI).
Hubble was the first telescope to resolve information within these numerous banana-shaped arcs. Thanks to its sharp vision, it can expose the shape and internal structure of the lensed background galaxies directly. In this way one can easily match the various arcs originating from the exact same background object– be it a galaxy or perhaps a supernova– by eye.
Gravitational lensing can be utilized to weigh clusters since the quantity of lensing depends on the overall mass of the cluster. This has significantly improved our understanding of the distribution of the covert dark matter in galaxy clusters and hence in deep space as a whole. The result of gravitational lensing also enabled an initial step towards exposing the secret of the dark energy.
As gravitational lenses operate as zoom glasses it is possible to use them to study remote galaxies from the early Universe, which otherwise would be impossibly faint to see due to their terrific distance from Earth.
The short article on the structure of the Universe has more details on Hubbles deal with dark matter.
” When we first observed the galaxy cluster Abell 2218 with Hubble in 1995 we generally intended at studying the cluster and its galaxies. When we revealed these ultrasharp images to our colleagues they might immediately see the value of utilizing gravitational lensing as a cosmological tool.”.
— Richard Ellis, Astronomer, University of Cambridge and California Institute of Technology.
In truth, the distant galaxy is much even more away and much smaller.Lensing clusters are clusters of elliptical galaxies whose gravity is so strong that they flex the light from the galaxies behind them. When light passes one of these enormous objects, such as a cluster of galaxies, its path is altered slightly.
If the lens is round then the image appears as an Einstein ring (in other words as a ring of light) (top); if the lens is extended then the image is an Einstein cross (it appears split into four unique images) (middle), and if the lens is a galaxy cluster, like Abell 2218, then arcs and arclets (banana-shaped images) of light are formed (bottom). The huge galaxy cluster in the center of this image contains so much dark matter mass that its gravity bends the light of more remote objects.” When we initially observed the galaxy cluster Abell 2218 with Hubble in 1995 we generally aimed at studying the cluster and its galaxies.
This illustration portrays a phenomenon referred to as gravitational lensing, which is utilized by astronomers to study extremely distant and really faint galaxies. Keep in mind that the scale has actually been greatly exaggerated in this diagram. In reality, the distant galaxy is much further away and much smaller.Lensing clusters are clusters of elliptical galaxies whose gravity is so strong that they flex the light from the galaxies behind them. This produces distorted, and typically multiple images of the background galaxy. Despite this distortion, gravitational lenses permit for considerably improved observations as gravity flexes the lights path towards Hubble, magnifying the light and making otherwise undetectable items observable.Credit: NASA, ESA & & L. Calçada
Light does not always take a trip in straight lines. As Einstein forecasted in his Theory of General Relativity, enormous items will deform the material of space itself. When light passes among these enormous items, such as a cluster of galaxies, its path is altered slightly.
This impact, called gravitational lensing, is just noticeable in rare cases and only the best telescopes can observe the related phenomena.
Gravitational lenses produce different shaped images depending upon the shape of the lensing body. If the lens is spherical then the image looks like an Einstein ring (simply put as a ring of light) (top); if the lens is lengthened then the image is an Einstein cross (it appears split into 4 unique images) (middle), and if the lens is a galaxy cluster, like Abell 2218, then arclets and arcs (banana-shaped images) of light are formed (bottom). Credit: European Space Agency
Hubbles sensitivity and high resolution permit it to see faint and far-off gravitational lenses that can not be spotted with ground-based telescopes whose images are blurred by the Earths environment. The gravitational lensing results in several images of the original galaxy each with a characteristically distorted banana-like shape and even into rings.
