Posted on 04/21/2019 8:51:24 AM PDT by DUMBGRUNT
The black hole is enormous, with a radius of roughly 9 billion miles...
The concept of a black hole goes back to the 18th century, when the English astronomer-clergyman John Michell calculated that a sufficiently large star couldn't shine because light wouldn’t move fast enough to “lift off” and escape the star’s gravity. But Michell’s conjecture outran the physics of its time, which didn’t understand light, gravity or stars well enough to support it. The foundations for the modern understanding of black holes weren’t laid until the early 20th century, building on James Clerk Maxwell’s theory of electromagnetism and Albert Einstein’s theory of relativity. In 1939, J. Robert Oppenheimer and Hartland Snyder wrote “On Continued Gravitational Contraction,” the most important paper in the history of black holes. ...Our own Milky Way galaxy also harbors a central, giant black hole, hidden from direct observation by enshrouding dust.
(Excerpt) Read more at wsj.com ...
Somehow, when I think of universal glory, black holes aren’t what come to mind. ;)
For me the glory of seeing something so far beyond common experience as a black hole is how it demonstrates the unlimited power of human curiosity and reasoning. Not even Einstein would accept the notion of a “real” black hole existing despite being shown by Karl Schwarzschild that it must exist as a mathematical limit condition on the General Theory of Relativity. That such a powerful cosmic event could result, ironically, from the interaction of the weakest known force in the universe, gravity, is beautiful. Without this weak gravitational force working its power of hydrogen gas molecules stars, heavier elements, and life itself would not have emerged from the primordial chaos of the early universe. The story is still incomplete because gravity is so weak it can’t yet be unified with the other known forces at the quantum level but with so many great minds like the students of Lee Smolin and Frank Wilczek working on this problem our human understanding will only increase with time.
Electric Universe ping.
This statement is a bit misleading. I assume the author is describing the Schwarzschild radius which is the radius of the boundary of Black hole. It is commonly known as the event horizon.
The event horizon is the boundary defining the region of space around a black hole from which nothing can escape, not even light.
Under General Relativity, a non-rotating black hole is contained in a region of infinitely small volume, where the curvature of space–time is infinite.
I did read “A Brief History of Time: From the Big Bang to Black Holes”, but it made my brain hurt.
That said, writer Wilczek is a very sharp cookie, I doubt he would need to mislead you.
Lost me at Mathematical limit. Why would e=Mc^2 have a limit?
For me the glory of seeing something so far beyond common experience as a black hole is how it demonstrates the unlimited power of human curiosity and reasoning.
*ping*
My choice of the word, mislead, was not appropriate to what I was intending to convey. It was a poor choice. For his sentence,
The black hole is enormous, with a radius of roughly 9 billion miles...
I was thinking the following when reading the sentence:
This statement will have most readers incorrectly assuming that a black hole would have an actual radius of 9 billion miles.
Here's the preceding paragraph; perhaps it will modify your assumptions?
On April 10, astronomers working with the Event Horizon Telescope unveiled a “photograph” of the monstrous black hole that sits at the center of the M87 galaxy, 54 million light years away. Viewed simply as an image, it is neither impressive nor straightforward: It presents a sort of nondescript, blurry, half-glazed doughnut, showing not the black hole itself but the shadow-like distortion it carves in the surrounding illumination. Yet, to a thinking mind, the image reflects the glory of understanding, and to an alert imagination it opens new portals into space, time and deep history.
The making of the image was a tour de force of science and technology. The black hole is enormous, with a radius of roughly 9 billion miles (or one hundred times the distance from the Earth to the sun) and a mass equivalent to two quadrillion Earths.
Wilczek even lived in Einstein's house!
For years!
Very smart guy.
English astronomer-clergyman John Michell calculated that a sufficiently large star couldn't shine because...
He just figured out what mass would result in an escape velocity that equalled the velocity of light. Thanks fieldmarshaldj.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.