“Mass tells space-time how to curve, and space-time tells mass how to move,” pioneering American physicist John Wheeler (1911-2008) once said. Wheeler was commenting on a result of Albert Einstein. General Relativity Theory (1915), who described how space-time can bend like the flexible fabric of a trampoline when a heavy object is placed on it. According to General relativity, the gravitational force can be explained by the warping that a massive object causes in the space around it, and this warping of space-time can result in strange shapes distorted in a way that has been compared to a funhouse mirror “at a carnival. In October 2019, astronomers published an image of the Hubble Space Telescope (HST) revealing a galaxy nicknamed the “Sunburst Arc” which has been split into a strange and enchanting kaleidoscopic illusion of a dozen images created by a massive foreground cluster of galaxies located 4.6 billion light-years away. This image beautifully demonstrates Einstein’s prediction that the gravity of massive objects in space should bend traveling light, thus causing some very strange distortions.
Imagine a child’s trampoline. A little girl takes a bowling ball and places it on the flexible fabric of the trampoline. Next, her brother takes a handful of marbles and throws them near where the bowling ball rests on the cloth. The marbles travel around the dimple created in the trampoline fabric by the heavy bowling ball. If the bowling ball is removed, the marbles travel along straight paths. The mass of the heavy bowling ball created a warp, a curvature, in the trampoline fabric that “told” the marbles how to move. The trampoline fabric is Spacetime.
Einstein’s view of warping space-time originated in 1919 from observations of a solar eclipse where the bending of space (the trampoline cloth) from the Sun (the bowling ball) could be measured. An additional prediction was that the deformation would create a gravitational-lensing which, in addition to distortion, would increase the apparent size and brightness of a distant object, behaving like a magnifying glass, much to the delight of astronomers who find such distortions valuable when observing distant objects in the Universe.
Mother Nature’s Magnifying Glass
The term gravitational lensing itself refers to the path that the traveling light has taken when it has been diverted. This happens when the mass of an object in the foreground distorts the light coming from a further object in the background. The light does not have to be visible light. It can be any form of electromagnetic radiation. Due to the effects of gravitational lensing, beams of light that normally would not have been observable are distorted in such a way that their paths wander toward the observer. However, light can also be deformed so that its beams travel far of the observer.
There are three different ways to gravitational lensing: strong lensing, weak lensing, Y microlenses The differences between the three types depend on the position of the background object that sends its light beams into space, the foreground object that serves as lens deforming that light, and the position of the observer. Also, the shape and mass of the foreground lens itself plays an important role. This foreground object is what determines how much light from the background object will be bent, as well as the path this light will take through space-time.
The Universe we see today shines brightly with the raging and fabulous fireworks of trillions upon trillions of stars. The sparkling stellar denizens of the Universe populate the billions of galaxies that inhabit the relatively small expanse of space-time we call the visible Prayed observable Universe. Observers are unable to see what may exist beyond the cosmological horizon (edge) of the visible Universe. That’s because the light emitted by the bright objects that inhabit those unimaginably remote regions hasn’t had enough time to reach us since the birth of the Universe in the Big Bang nearly 14 billion years ago. The expansion of the Universe and the finite speed of light have made such a journey impossible.
The speed of light establishes a kind of universal speed limit: no known signal can travel faster than light in a vacuum. We cannot see what may exist beyond the cosmological horizon, and the greatest of all mysteries, the unanswered secret of our very existence, may lie in those very remote realms far beyond our visibility. When we look deep into Space, we look back in Time. The more distant a luminous object is in space, the longer it has taken for its light stream to reach us. It is impossible to locate an object in Space, without also locating it in Time (space time). The three spatial dimensions that characterize our familiar world are up and down, front and back, and side to side. Time is the fourth dimension.
gravitational lensing can dramatically magnify remote sources in the ancient Universe, Yes there is a sufficiently massive object lurking in the foreground that it is situated between the background source and the prying eyes of curious observers.
It was not until 1979 that the first gravitational-lensing it was confirmed. An otherwise dark galaxy served as lens and divided and magnified the light from a remote control quasar located far back in a duet of images. gravitational lens Today’s observations are frequently used to discover new exoplanets stars orbiting beyond our Sun. Astronomers zoom in on very remote galaxies and then map the distribution of what would otherwise be transparent and invisible. dark matter.
dark matter it is believed to be an exotic form of matter made up of non-atomic particles, which do not interact with light, which is why it is invisible. It is believed to be the most abundant form of matter in the Universe, far more abundant than the “ordinary” atomic matter that makes up our familiar world. Because dark matter it is transparent, it does not interact with visible objects except through the force of gravity, its existence has not been directly verified. It is thought to play the important role of the gravitational “glue” that holds galaxies together, and its gravitational effects on observable objects indicate that it probably lurks like a ghost in the Cosmos.
glasses in the sky
gravitational lens reveals that the foreground galaxy cluster magnifies the sunburst arch it is so extremely massive that its powerful gravity warps the fabric of space-time, bending and magnifying the light emitted by it. sunburst arch located far behind him. This distortion effect also creates multiple images of the same galaxy.
Tea sunburst arch is located almost 11 billion light years from our planet, and has been with lens in multiple images by the massive cluster of foreground galaxies that lie between the sunburst arch and the earth Tea glasses The phenomenon created at least a dozen images of this distant background galaxy, distributed in a quartet of main arcs. Three of these arches can be seen at the top right of the HST image, while a counter arch is located at the bottom left. However, the counterarc is partially obscured by a very bright foreground star in our Milky Way.
HST uses these gravitational magnifying glasses in space-time to study objects that would otherwise be too dim, too distant, and too small for even very sensitive instruments to detect. Tea sunburst archeven though he is one of the brightest of gravitational lens galaxies is no exception. without the foreground lens by magnifying and distorting its distant light, it would be too faint for astronomers to detect.
Tea lens Images created from sunburst arch are between 10 and 30 times brighter than this background galaxy would be without the effects of gravitational glasses. The extension enabled HST to look at structures as small as 520 light-years across that would otherwise be too tiny to observe without Mother Nature’s gift of a lens. The structures resemble star birth regions in nearby galaxies in the local Universe. This helped astronomers make a detailed study of the remote galaxy and its surroundings.
HST observations reveal that the sunburst arch it is very much like galaxies that existed much earlier in the history of the Universe, perhaps as little as 150 million years ago after the Big Bang.