Could it really be that it’s been one hundred years since Albert Einstein published his theory of general relativity? The science community refers to Albert so often, I often feel as if he graced this earth just yesterday. But, indeed, November is the one hundred year anniversary of his publication of this theory.
Even though the gringa has heard many times someone say “the theory of relativity”, um, what the heck does it really mean? I mean, how the heck can it be used for something useful or even for something interesting or fun? Well, this is the basis for all the time-warp fodder for great (or even lousy) literary works of science fiction, which the gringa loves, even the “lousy” ones.
The first time Albert’s theory was successfully put to the test in real life was during the observation of a solar eclipse. A prediction was made, based on the theory, of how much “bended” light would be deflected when a particular star passed near the sun. The theory supposed that the sun’s mass would cause the light of the star to bend. And the prediction, based on Albert’s theory, was spot on.
So? Now what? Thus became the established phenomena that is known as “gravitational lensing”. Astronomers now know that this appearance of bended light is not an optical illusion but something that actually happens. This allows astronomers a method to delve into galaxies that would otherwise be off limits for research even with humanity’s most powerful telescopes.
One such galaxy that fits this description is commonly called the “Cheshire Cat” galaxy because it’s appearance reminds one of that particular elusive character from the “Alice In Wonderland” story. What exactly causes the smiley face? Well, the theory explains that these are distant galaxies whose light is stretched and then bent by objects of great mass which are most likely made up of dark matter. Why dark matter? Well, since no large mass objects are visible but the evidence of their presence is there in the bent light, the mass must then exist in the form of invisible dark matter.
Scientists claim that there are six galaxies that make up the outer space smiley face. Each eye and the nose are individual galaxies and there are four other galaxies that create the arcs which are bent light created by gravitational lensing by some mysterious dark matter object with great mass. Scientists view the “Cheshire Cat” through NASA’s Hubble Space Telescope.
The eye galaxies are the brightest and are zipping through space on a collision course with one another at over 300,000 miles per hour. NASA uses the Chandra X-ray Observatory to determine that hot gas, millions of degrees Fahrenheit, is the evidence that these galaxies are indeed colliding. And that’s not all the mayhem that the “Cheshire Cat” is out and about doing. Aside from the bumper car routine, the cat’s left eye has a very hungry supermassive black hole right at its center which is gobbling up all sorts of things.
Astronomers classify this cluster of galaxies as a fossil group. A fossil group has a dominant elliptical galaxy surrounded by smaller galaxies. Fossil groups are considered to be just one stage that almost all galaxy groups go through as they evolve. Perhaps it’s kind of like the teenage years for galaxies. Horrible driving and collisions and they eat everyone out of house and home.
So, once it grows up a bit, then, what’s the next stage? That would be the Cyclops group, when they merge into one mega-galaxy. Yeah, the gringa thinks that sounds about right. Just like a teenager then develops into a mature senior who gets a bit fat and needs reading glasses. But it will probably take a billion years or so. Looks like we will be enjoying the smiley face for a long time to come.
If any of the gringa’s dear readers happen to be passing through Huntsville, Alabama, they can check in at Marshall Space Flight Center. That’s headquarters for the Chandra program that studies the “Cheshire Cat”. Or, even better, if you find yourself in Cambridge, Massachusetts, see if you can take a peek at the cat yourself. That’s where you’ll find The Smithsonian Astrophysics Observatory that controls the Chandra program’s science and flight operations.
Source and Photo Credit: www.nasa.gov