Its another edition of In Galileo’s Shadow. I’m Gimmick Commander Ben Faltinowski.
Is there a way to tell a real Black Hole picture from an artists concept drawing? Its now been confirmed that there IS!
Today, the astronomy world got some fantastic news. For the first time in history, theoretical knowledge and calculations about black holes were finally made sight. From NASA to National Geographic, all related news sites reported that a supermassive black hole was discovered and seen in the super galaxy M87.
What is a black hole? From various resources, like Wikipedia, a black hole is a region of spacetime exhibiting such strong gravitational effects that nothing—not even particles and electromagnetic radiation such as light—can escape from inside it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, no locally detectable features appear to be observed. In many ways, a black hole acts as an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is on the order of billionths of a Kelvin for black holes of stellar mass, making it essentially impossible to observe.
Part of the Event Horizon Telescope network
So how was this black hole seen? Out of curiosity, I decided to read more about it and came upon information that discussed the Event Horizon Telescope (EHT). It is a project to create a large group of telescopes that work together, consisting of a global network of radio telescopes combining data from several interferometry stations around the Earth. The goal is to observe the immediate environment of the supermassive black hole Sagittarius A* at the center of the Milky Way as well as the even larger black hole in the center of the supergiant elliptical galaxy Messier 87.
Today, on April 10, 2019, the first image of the black hole inside galaxy Messier 87 was published. The black hole was given the name Pōwehi, meaning “embellished dark source of unending creation” in the Hawaiian language.
The EHT is composed of many radio observatories or radio telescope facilities around the world to produce a high-sensitivity, high-angular-resolution telescope.
Through the technique called very-long-baseline interferometry (VLBI), many independent radio antennas separated by hundreds or thousands of miles can be used together to create a virtual telescope with an effective diameter of the Planet Earth, or roughly 12,000+ miles. The effort includes development and deployment of dual polarization receivers, highly stable frequency standards, and other tools.
Artist rendition of Sagittarius A*, The supermassive black hole at the center of the Milky Way.
Since 2006, the EHT array has moved to add more observatories to its global network of radio telescopes. The first image of the Milky Way’s supermassive black hole, Sagittarius A*, was expected to be produced in April 2017, but because the South Pole Telescope is closed during winter (April to October), this delayed the processing to December 2017 when the shipment arrived.
MIT Haystack Observatory and Planck Institute of Radio Astronomy.
Data collected on hard drives are transported from the various telescopes to the MIT Haystack Observatory in Massachusetts, USA, and the Max Planck Institute for Radio Astronomy, Bonn, Germany, where the data is analyzed and researched on a grid computer.
Pōwehi (M87*), the first observed Black Hole via the EHT.The Event Horizon Telescope Collaboration announced its first results in simultaneous press conferences worldwide on April 10, 2019. The announcement featured the first-ever direct image of a black hole named Pōwehi (M87*), which showed the supermassive black hole at the center of Messier 87. The scientific results were presented in a series of six papers published in The Astrophysical Journal Letters.
A motion image of a Black Hole.
The image provided new measurements for the mass and diameter of M87* (the Black Hole). EHT measured the black hole’s mass to be approximately 6.5 billion solar masses and measured the diameter of its event horizon to be approximately 40 billion km, roughly 2.5 times smaller than the shadow that it casts, seen at the center of the image.
From the asymmetry in the ring, EHT inferred that the matter on the brighter south side of the disk is moving towards Earth, the observer. This is based on the theory that approaching matter appears brighter because of a relativistic light beaming effect. Previous observations of the black hole’s jet showed that the black hole’s spin axis is inclined at an angle of 17° relative to the observer’s line of sight. From these two observations, EHT concluded the black hole spins clockwise, as seen from Earth.
Dr. Stephen Hawking and a Black Hole Image.
It truly is a great day for astronomy and for those who have researched black holes. It’s also too bad that Dr. Stephen Hawking did not live at least 18 months longer to be able to see what he postulated made visible to the world. But we now have the methods to be able to look for this extraordinary phenomenon and no doubt over time many more sightings of black holes can be expected.
To learn more about today’s announcement and The Event Horizon Telescope, visit HERE for more info.
For the Great Galactic Space Gimmick, I’m Gimmick Commander Ben Faltinowski! ???
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