A brand new image from the Hubble Space Telescope gazes into the lair of a cosmic leviathan, a monstrous cluster of galaxies situated nine billion light-years away within the constellation Draco.
Like a sea monster in ancient myth submerged and waiting to grab unlucky sailors to their doom, this celestial beast may be seen by the ripples around it. This leviathan is so titanic, nevertheless, that the ripples aren’t traveling the surface of an ocean or lake but fairly are distortions in the material of space-time itself.
This particular galaxy cluster, referred to as eMACS J1823.1+7822, is one in every of five chosen for remark by Hubble astronomers to find out the strength of this “warping” effect, which was first predicted by Albert Einstein’s theory of general relativity.
The 1915 theory, which is occasionally called Einstein’s geometric theory of gravity, predicts that, as bowling balls placed on a trampoline create a depression, objects with mass cause the very fabric of space-time to warp. This curvature gives rise to the force of gravity. And the greater the mass of a cosmic object, the more extreme the warping of space it causes.
Light travels across the universe in straight lines, but when it encounters a warp brought on by a very massive object, its path is curved. When the warping object is between Earth and a background object, it might curve light in such a way that the apparent position of the background object is shifted.
But when the intermediate or “lensing object” is actually massive — like a monstrous cluster of galaxies, for instance — light from the background source takes a distinct period of time to achieve Earth depending on how close it passes to the natural cosmic lens.
This effect, called gravitational lensing, could make single objects appear at multiple points within the sky, often in stunning arrangements called Einstein rings and Einstein crosses. It may well also cause background objects to look amplified within the sky, a strong effect that astronomers use to watch distant and early faint galaxies.
The distortion brought on by massive clusters like eMACS J1823.1+7822 can even help astronomers study mysterious dark matter, which accounts for around 85% of the mass within the universe but is invisible since it doesn’t interact with electromagnetic radiation. Because dark matter does interact gravitationally, nevertheless, the lensing of sunshine by a galaxy or galactic cluster might help researchers map the distribution of dark matter.
In the brand new Hubble image, eMACS J1823.1+7822, made up of a set of elliptical galaxies, acts as a gravitational lens. The cluster warps the form of the galaxies around it, giving them a rather elongated shape, turning some into arcs and others into vivid streaks.
This particular image was created using Hubble’s Advanced Camera for Surveys and its Wide Field Camera 3 instrument, each of which have the power to view galaxies and stars in specific wavelengths of sunshine. Observing objects at different wavelengths in this fashion allows for a more complete picture of the structure, researchers say.
In turn, such observations can reveal the composition and behavior of an object that will be hidden in visible light alone. When combined with using clusters like eMACS J1823.1+7822, gravitational lensing allows this to be done for a few of the universe’s earliest galaxies. So powerful observatories like Hubble and the James Webb Space Telescope can probe conditions found shortly after the Big Bang and the very birth of the universe.
