Gravity warps space in strange and counter-intuitive ways, and the bigger the source of gravity, the bigger the warping. One example of gravity’s optical illusions is beautiful rings in space named Einstein rings, one of which was recently captured by the Hubble Space Telescope.
Named for the physicist who predicted gravity’s strange stretching influence on space, studying rings like the one shown below can help astronomers peer out far into the distance, seeing a galaxy as it looked over 9 billion years ago.
The narrow galaxy elegantly curving around its spherical companion in this image is a fantastic example of a truly strange and very rare phenomenon. This image, taken with the NASA/ESA Hubble Space Telescope, depicts GAL-CLUS-022058s, located in the southern hemisphere constellation of Fornax (The Furnace). GAL-CLUS-022058s is the largest and one of the most complete Einstein rings ever discovered in our Universe. ESA/Hubble & NASA, S. Jha; Acknowledgement: L. Shatz
The object might look like a ring, but the source of the light is actually a regular old galaxy. The ring shape forms due to a phenomenon called gravitational lensing, in which the light from the distant galaxy is warped by the gravity of a galaxy cluster in between it and us.
Not only does this phenomenon change the apparent shape of the galaxy, but it also magnifies and brightens it. The galaxy appears 20 times brighter due to the lensing effect, which allowed Hubble to image it with the equivalent of an enormous 48-meter-aperture telescope.
This particular ring is formally known as GAL-CLUS-022058s, but it has a more colloquial nickname as well: The Molten Ring, which is appropriately located in the constellation of Fornax (the Furnace). This image was shared as a Hubble picture of the week in December last year, and since then researchers have been studying the ring using other tools as well like the European Southern Observatory’s Very Large Telescope (VLT) FORS instrument.
By looking at this ring, researchers can learn about a very distant galaxy, effectively looking back in time to when the universe was less than half of its current age. This period was a busy, active one in which many stars were being born.
“The lensed galaxy is one of the brightest galaxies in the millimeter wavelength regime,” said one of the authors, Helmut Dannerbauer of the Institute of Astrophysics of the Canary Islands in Spain. “Our research has also shown that it is a normal star-forming galaxy (a so-called main sequence galaxy) at the peak epoch of star formation in the Universe.”