Black Hole Friday
"If you want to see a black hole tonight, tonight just look in the direction of Sagittarius, the constellation. That's the center of the Milky Way Galaxy and there's a raging black hole at the very center of that constellation that holds the galaxy together."
~ Michio Kaku
Black Hole Friday is an informal name for the Friday following Thanksgiving Day in the United States, a term co-opted from retailers by Astronomers and Science Teachers to highlight science and the study of Black Holes! The idea of a body so massive that even light could not escape was briefly proposed by astronomical pioneer and English clergyman John Michell in a letter published in November 1784! Albert Einstein first predicted the existence of black holes in 1916, with his general theory of relativity though the term "black hole" was not coined until many years later in 1967 by American astronomer John Wheeler. After decades of theoretical speculation, the first physical black hole ever discovered was spotted in 1971. Black holes come in miniature, middling and mammoth sizes. Supermassive black holes are the biggest in the universe, some with masses billions of times that of our sun! The Milky Way galaxy alone is thought to harbor some 100 million stellar-mass black holes, plus supermassive Sagittarius A* (Sgr A*) at its heart, which contains the mass of about 4 million suns! Recently in 2020, astronomers using the NASA/ESA Hubble Space Telescope observed spectacular large-scale dark and light rays beaming out of the bright center of IC 5063, an active galaxy located 156 million light-years away in the southern constellation of Indus. Researchers believe that a torus-shaped ring of dusty material surrounding IC 5063’s central black hole is casting its X-shaped shadow into space. Watch out! ☀️ ☀ ⚫ 🔭
Humorously celebrated by NASA (National Aeronautics and Space Administration) "Black Hole Friday" (a pun on the traditional post Thanksgiving shopping day in the United States called "Black Friday") is used to educate and spread awareness of Astronomy in general, and black holes in particular.
The past years have seen spectacular advancements in the sciences, but particularly for the repeated observation of gravitational waves. In 2017, the Royal Swedish Academy of Sciences awarded physicists Rainer Weiss, Kip Thorne, and Barry Barish the Nobel Prize in physics for directly detecting gravitational waves—wrinkles in space-time predicted more than a century ago by Einstein’s theory of general relativity, but which had been elusive until 2015.
The most recent observations were made by the Laser Interferometer Gravitational-Wave Observatory (LIGO), a large-scale physics experiment and observatory designed to detect cosmic gravitational waves and to develop gravitational-wave observations as an astronomical tool.
Gravitational waves are 'ripples' in the fabric of space-time caused by some of the most violent and energetic processes in the Universe. Albert Einstein predicted the existence of gravitational waves in his general theory of relativity.
As of now, gravitational waves have been detected multiple times by collisions of black holes and most recently, by the collision of two neutron stars, a special event because this allows physicist to correlate the wave event with something visible!
The first detected observable wave was created when two black holes spiraled toward one another. Ripples in spacetime spread from the collision at the speed of light until, for about a second on December 25, 2015 (if you were in the United States), the space holding the atoms that make you up buckled and then relaxed.
The waves first hit the observatory/detector in Livingston, Louisiana, and then 1.1 milliseconds later passed through the one in Hanford, Washington. For this event, space buckled enough to move the mirrors of both detectors by 0.7 attometers. That’s 7 tenths of a millionth of a trillionth of a meter!
On April 10, 2019, the first image of a black hole, showing the ring of bright gasses emitted near the black hole's event horizon was released. Two telescopes on Maunakea – the James Clerk Maxwell Telescope (JCMT) and Submillimeter Array (SMA) – joined six other observatories around the world to take part in the unprecedented Event Horizon Telescope project, resulting in the April 2017 capture of a look at the supermassive black hole at the center of the Messier 87 galaxy, which is about 50 million light years away.
Astronomers collaborated with renowned Hawaiian language and cultural practitioner Dr. Larry Kimura for the Hawaiian naming of the black hole. Pōwehi, meaning embellished dark source of unending creation, is a name sourced from the Kumulipo, the primordial chant describing the creation of the Hawaiian universe.
Carol A.L. Martin's tartan "Black Hole" is designed to reflect the fundamentals of our universe - galaxies, black holes and quasars.
Click the photo of the latest Hubble photography of galaxy IC 5063 from NASA.