Experimental Blog # 204

Quotations and comments on "Black Hole" - How an Idea Abandoned by Newtonians, Hated by Einstein,, and Gambled on by Hawking Became Loved by Marcia Bartusiak and "Black Hole Blues and Other Songs from Outer Space" by Janna Levin

From "Black Hole" by Marcia Bartusiak:

"After a flurry of excitement in 1919 < > the noted physicist's new outlook on gravity came to be ignored. Isaac Newton's take on gravity worked just fine in our every day world of low velocities and normal stars, so why be concerned with the minuscule adjustments that general relativity offered? < > By the time that Einstein died, in 1955, general relativity was in the doldrums."
"Not until astronomers revealed surprising new phenomena in the universe, brought about with advanced technology, did scientists take a second and more serious look at Einstein's view of gravity. Observers in 1963 identified the first quasar, a remote young galaxy disgorging the energy of a trillion suns from its center. < > With the detection of these new objects"{pulsars, neutron stars, black holes},"the once sedate universe < > metamorphosed into an Einsteinian cosmos, filled with sources of titanic energy that can be understood only in the light of relativity."

In papers published in 1767 and 1783 the English scientist John Michell first theorized about double stars, which rotate about each other, and stars "when the mass of the star would be so great that "all light ... would be made to return towards, by its own proper gravity"_"
"In 1796 < > the {French} mathematician Pierre-Simon de Laplace independently arrived at a similar conclusion."

"And from his equations alone, Maxwell had revealed a new, fundamental constant in nature - the speed of light."
"Einstein didn't completely overturn Newton's law of gravity. Newton got us to the moon and back just fine < > Newton's equations can handily deal with gravity in that environment."
"In Zwicky's day, neutron stars remained theoretical fabrications, which astronomers figured would never be seen even if they did exist, due to their extremely small size. {That all changed when the first bona fide neutron star, beeping away as a radio pulsar, was first discovered by the British astronomer Jocelyn Bell in 1967}."

"Ultimately, physicists want a theory to connect with the world. You could argue that quantum mechanics was just as weird < > Why was it so readily accepted and general relativity snubbed? It's primarily because quantum theorists worked hand in hand with experimentalists. There was a deep pool of experimental data to support quantum mechanics' predictions on the nature and behavior of matter{weird as it was} on very small scales."

"The high-stability clocks aboard the Global Positioning System{GPS} satellites, perched high above the Earth, run a bit faster. As a result, periodic corrections for general relativity must be programmed in to make sure the navigation of our cars, boats,and planes down here on Earth doesn't go awry{perhaps the first time that general relativity was needed to help us in our everyday lives}."

And from "Black Hole Blues" by Janna Levin:

"Summarizing the decades of contributions < > Stars like our sun will die as white dwarfs, a cool sphere of degenerate matter comparable in size to the Earth, the pressure of densely packed electrons enough to resist total collapse. Heavier dead stars will stably end as neutron stars, an even denser sphere of nuclear degenerate matter around 20 to 30 kilometers across, the pressure of densely packed neutrons enough to resist total collapse. But the heaviest stars have no more recourse to nuclear pressure. Unhindered collapse is inevitable."

"Conceptually, gravitational waves are required out of respect for the speed limit. As one black hole orbits another, the curves in the shape of spacetime must drag around with them < > As the black holes move, the curves shift and adjust, and those changes wave outward incrementally and at the speed of light, carrying energy away from the violent astrophysical motions."

"quasars, bright radio sources that looked as small as stars{formerly, quasi-stellar radio objects}"
"Pulsars are highly magnetized rapidly spinning neutron stars."
"White dwarfs and neutron stars are extremely faint. We cannot see them if they're far away, extragalactic. We can see evidence for them in our own Milky Way galaxy.."

"In the Milky Way, there may be one neutron star collision with another neutron star every ten thousand years <> There may be one neutron star collision with a black hole every few hundred thousand years. There may be one black hole collision with another black hole every couple million years."
"LIGO must record the ringing of space originating from within millions of galaxies in order to record black hole collisions on a scientifically reasonable scale ..."