The perfect
circle of observable light that's surrounding a galaxy cluster in a new Hubble
Space Telescope image is a visual indicator of the huge masses that are bending
time and space in that region. The galaxy cluster, called SDSS J0146-0929,
features hundreds of individual galaxies all bound together by gravity.
The graceful arcs at the center of this image from the Hubble Space Telescope are actually the distorted light of distant galaxies, twisted to form an "Einstein ring" by the gravitational influence of the closer galaxy cluster SDSS J0146-0929. Credit: ESA/Hubble & NASA; Acknowledgment: Judy Schmidt
There's so
much mass in this region that the cluster is distorting light from objects
behind it. This phenomenon is called an Einstein ring. The ring is created as
the light that comes from distant objects, like galaxies, passes by “an
extremely large mass, like this galaxy cluster.”
NASA said in
a statement:
“In this
image, the light from a background galaxy is diverted and distorted around the
massive intervening cluster and forced to travel along many different light
paths toward Earth, making it seem as though the galaxy is in several places at
once.”
The ring is
named after Albert Einstein, who wrote his theory of general relativity in the
early 1900s. In it, he suggested that a massive object would warp space and
time. This process is known today as a gravitational lens.
When the
most massive galaxies and galaxy clusters get in line with a more distant
object, they produce an Einstein ring – a type of gravitational lens. Einstein
rings (and gravitational lenses more generally) give astronomers a huge
advantage when they are trying to look at faraway objects. The rings and lenses
magnify objects that otherwise would be too distant and dim to see in today's
telescopes.
In 2015, for
example, astronomers took advantage of an Einstein ring to look at star-forming
regions in a galaxy formed just 2.4 billion years after the Big Bang. This will
provide more insight into how galaxies came together in the early universe.
Another Einstein ring popped up in 2016, in a star group within the Sculptor
dwarf galaxy. At the time, researchers said there are less than a dozen known
Einstein rings that are partial or full.
The
scientific team added that they plan to use this particular Einstein ring in
Sculptor to probe the nature of dark matter. This may help scientists learn
about the large-scale structure of the universe, since roughly 80 percent of it
is made up of dark matter and dark energy, which cannot be directly observed.
Via Space.com
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