Jagartrott wrote:Astro-physics is so fascinating. Black holes, multiverses, space-time, dark matter, singularities. It is a triumph of science that we are able to find things that we cannot observe.
Did you know that because gravity and time are dependent, that they have to adjust satellite clocks to match ours down at the surface? If you would wait a minute just outside the 'event horizon' of a black hole, 1000 years would have passed on earth. Time travel (only forward) is possible.
Kwibus wrote:So much quesions they have. Answers they will never get.
So why questions? If no answers?
-Kwibus, one of the great philosophers of the 21st century
Three lies in this statement : Galileo died at age 77, so he could not have been 80 during his trial, he’s never seen the Inquisition’s dungeons and he never demonstrated the motion of the Earth, let alone by irrefragable proof. Voltaire was a serial liar. For example, he’s the one that invented the myth that the “Man in the Iron Mask” was one of King Louis XIV’s siblings whose existence would discredit the King’s reign, while such a secret is obviously impossible to keep (read Jean-Christian Petitfils or Michel Vergé-Franceschi about The Man in the Iron Mask).« The great Galileo, at the age of four score, groaned away his days in the dungeons of the Inquisition because he had demonstrated by irrefragable proof the motion of the Earth ».
At least he was correct about the age.“Galileo’s enemies made him moan in dungeons, at age 70, for having known the earth movement, what is more shameful is that they forced him to retract.”
So again, Galileo has never been kept in a dungeon, he was far from being threatened to torture (60+ year old convicts were never tortured) and his heresy was not expressing a VIEW but claiming it was the right one without backing it up with convincing arguments.“[Galileo languished] in a Catholic dungeon threatened with torture [for his] heretic view that the earth moved about the sun”.
"after his sensational discoveries in 1610, Galileo neglected both observational research and astronomic theory in favour of his propaganda crusade. By the time he wrote the Dialogue he had lost touch with new developments in that field, and forgotten even what Copernicus had said."
(Arthur Koestler, 1959).“I am convinced that the conflict between the Church and Galileo (or Copernicus, for that matter) was not inevitable; it was not a collision waiting to happen between two incompatible philosophies, or a war fated to erupt sooner or later. Rather I believe it was a clash of personalities, of individuals, aggravated by unfortunate coincidences. In other words, I consider it naïve and wrong to see in Galileo’s trial a kind of Greek tragedy, a one-on-one battle between ‘blind faith’ and ‘enlightened reason’”
Just over a billion years ago, many millions of galaxies from here, a pair of black holes collided. They had been circling each other for aeons, in a sort of mating dance, gathering pace with each orbit, hurtling closer and closer. By the time they were a few hundred miles apart, they were whipping around at nearly the speed of light, releasing great shudders of gravitational energy. Space and time became distorted, like water at a rolling boil. In the fraction of a second that it took for the black holes to finally merge, they radiated a hundred times more energy than all the stars in the universe combined. They formed a new black hole, sixty-two times as heavy as our sun and almost as wide across as the state of Maine. As it smoothed itself out, assuming the shape of a slightly flattened sphere, a few last quivers of energy escaped. Then space and time became silent again.
The waves rippled outward in every direction, weakening as they went. On Earth, dinosaurs arose, evolved, and went extinct. The waves kept going. About fifty thousand years ago, they entered our own Milky Way galaxy, just as Homo sapiens were beginning to replace our Neanderthal cousins as the planet’s dominant species of ape. A hundred years ago, Albert Einstein, one of the more advanced members of the species, predicted the waves’ existence, inspiring decades of speculation and fruitless searching. Twenty-two years ago, construction began on an enormous detector, the Laser Interferometer Gravitational-Wave Observatory (LIGO). Then, on September 14, 2015, at just before eleven in the morning, Central European Time, the waves reached Earth. Marco Drago, a thirty-two-year-old Italian postdoctoral student and a member of the LIGO Scientific Collaboration, was the first person to notice them. He was sitting in front of his computer at the Albert Einstein Institute, in Hannover, Germany, viewing the LIGO data remotely. The waves appeared on his screen as a compressed squiggle, but the most exquisite ears in the universe, attuned to vibrations of less than a trillionth of an inch, would have heard what astronomers call a chirp—a faint whooping from low to high. This morning, in a press conference in Washington, D.C., the LIGO team announced that the signal constitutes the first direct observation of gravitational waves.
LIGO consists of two facilities, separated by nearly nineteen hundred miles—about a three-and-a-half-hour flight on a passenger jet, but a journey of less than ten ten-thousandths of a second for a gravitational wave. The detector in Livingston, Louisiana, sits on swampland east of Baton Rouge, surrounded by a commercial pine forest; the one in Hanford, Washington, is on the southwestern edge of the most contaminated nuclear site in the United States, amid desert sagebrush, tumbleweed, and decommissioned reactors. At both locations, a pair of concrete pipes some twelve feet tall stretch at right angles into the distance, so that from high above the facilities resemble carpenter’s squares. The pipes are so long—nearly two and a half miles—that they have to be raised from the ground by a yard at each end, to keep them lying flat as Earth curves beneath them.
LIGO is part of a larger effort to explore one of the more elusive implications of Einstein’s general theory of relativity. The theory, put simply, states that space and time curve in the presence of mass, and that this curvature produces the effect known as gravity. When two black holes orbit each other, they stretch and squeeze space-time like children running in circles on a trampoline, creating vibrations that travel to the very edge; these vibrations are gravitational waves. They pass through us all the time, from sources across the universe, but because gravity is so much weaker than the other fundamental forces of nature—electromagnetism, for instance, or the interactions that bind an atom together—we never sense them.
Weiss’s detection method was…make the observatory “L”-shaped. Picture two people lying on the floor, their heads touching, their bodies forming a right angle. When a gravitational wave passes through them, one person will grow taller while the other shrinks; a moment later, the opposite will happen. As the wave expands space-time in one direction, it necessarily compresses it in the other. Weiss’s instrument would gauge the difference between these two fluctuating lengths, and it would do so on a gigantic scale, using miles of steel tubing. “I wasn’t going to be detecting anything on my tabletop,” he said.
To achieve the necessary precision of measurement, Weiss suggested using light as a ruler. He imagined putting a laser in the crook of the “L.” It would send a beam down the length of each tube, which a mirror at the other end would reflect back. The speed of light in a vacuum is constant, so as long as the tubes were cleared of air and other particles the beams would recombine at the crook in synchrony—unless a gravitational wave happened to pass through. In that case, the distance between the mirrors and the laser would change slightly. Since one beam would now be covering a shorter distance than its twin, they would no longer be in lockstep by the time they got back. The greater the mismatch, the stronger the wave. Such an instrument would need to be thousands of times more sensitive than any previous device, and it would require delicate tuning in order to extract a signal of vanishing weakness from the planet’s omnipresent din.
In 1990, after years of studies, reports, presentations, and committee meetings, Weiss, Thorne, and Drever persuaded the National Science Foundation to fund the construction of LIGO. The project would cost two hundred and seventy-two million dollars, more than any N.S.F.-backed experiment before or since. “That started a huge fight,” Weiss said. “The astronomers were dead-set against it, because they thought it was going to be the biggest waste of money that ever happened.”
… “It never should have been built,” Isaacson told me. “It was a couple of maniacs running around, with no signal ever having been discovered, talking about pushing vacuum technology and laser technology and materials technology and seismic isolation and feedback systems orders of magnitude beyond the current state of the art, using materials that hadn’t been invented yet.”
It took years to make the most sensitive instrument in history insensitive to everything that is not a gravitational wave. Emptying the tubes of air demanded forty days of pumping. The result was one of the purest vacuums ever created on Earth, a trillionth as dense as the atmosphere at sea level. Still, the sources of interference were almost beyond reckoning—the motion of the wind in Hanford, or of the ocean in Livingston; imperfections in the laser light as a result of fluctuations in the power grid; the jittering of individual atoms within the mirrors; distant lightning storms. All can obscure or be mistaken for a gravitational wave, and each source had to be eliminated or controlled for. One of LIGO’s systems responds to minuscule seismic tremors by activating a damping system that pushes on the mirrors with exactly the right counterforce to keep them steady; another monitors for disruptive sounds from passing cars, airplanes, or wolves.
The LIGO team includes a small group of people whose job is to create blind injections—bogus evidence of a gravitational wave—as a way of keeping the scientists on their toes. Although everyone knew who the four people in that group were, “we didn’t know what, when, or whether,” Gabriela González, the collaboration’s spokeswoman, said. During Initial LIGO’s final run, in 2010, the detectors picked up what appeared to be a strong signal. The scientists analyzed it intensively for six months, concluding that it was a gravitational wave from somewhere in the constellation of Canis Major. Just before they submitted their results for publication, however, they learned that the signal was a fake.
The September 14th detection, now officially known as GW150914, has already yielded a handful of significant astrophysical findings. To begin with, it represents the first observational evidence that black-hole pairs exist. Until now, they had existed only in theory, since by definition they swallow all light in their vicinity, rendering themselves invisible to conventional telescopes. Gravitational waves are the only information known to be capable of escaping a black hole’s crushing gravity.
The detection also proves that Einstein was right about yet another aspect of the physical universe. Although his theory deals with gravity, it has primarily been tested in our solar system, a place with a notably weak gravitational regime. “You think Earth’s gravity is really something when you’re climbing the stairs,” Weiss said. “But, as far as physics goes, it is a pipsqueak, infinitesimal, tiny little effect.” Near a black hole, however, gravity becomes the strongest force in the universe, capable of tearing atoms apart. Einstein predicted as much in 1916, and the LIGO results suggest that his equations align almost perfectly with real-world observation. “How could he have ever known this?” Weiss asked. “I would love to present him with the data that I saw that morning, to see his face.”
As it happens, the particular frequencies of the waves that LIGO can detect fall within the range of human hearing, between about thirty-five and two hundred and fifty hertz. The chirp was much too quiet to hear by the time it reached Earth, and LIGO was capable of capturing only two-tenths of a second of the black holes’ multibillion-year merger, but with some minimal audio processing the event sounds like a glissando. “Use the back of your fingers, the nails, and just run them along the piano from the lowest A up to middle C, and you’ve got the whole signal,” Weiss said.
Different celestial sources emit their own sorts of gravitational waves, which means that LIGO and its successors could end up hearing something like a cosmic orchestra. “The binary neutron stars are like the piccolos,” Reitze said. Isolated spinning pulsars, he added, might make a monochromatic “ding” like a triangle, and black holes would fill in the string section, running from double bass on up, depending on their mass. LIGO, he said, will only ever be able to detect violins and violas; waves from supermassive black holes, like the one at the center of the Milky Way, will have to await future detectors, with different sensitivities.
on3m@n@rmy wrote:Thanks for the narrative, MI. As I was reading that, my first question was how do they account for infinitesimal disturbances such as weak seismic activity, which the narrative addressed.
Another topic that has raised my curiosity is quantum physics. Specifically, quantum entanglements between two particles that spin in unison in opposite directions, even when the particles are separated by many miles. This discovery has in some way been used to support the idea of alternate universes. Anyway, google quantum physics for dummies and you can find information on this (https://www.youtube.com/watch?v=JP9KP-fwFhk is one example). It starts off with describing what a quantum leap is, particle waves, before finally getting into entanglements about half way through the video. Hats off to you if you can tolerate London Girl's narrative.
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