Kip Thorne Explains Black Hole

[Vernon]

KipThorne has recently been in the public eye as the physicist who brought real-world physics to the science fiction epic "Interstellar." But this isn't Thorne's first foray into discussing this kind of mind-bending science with the public: 20 years ago, Thorne wrote a best-selling book about black holes and other awesome astrophysical phenomena for a general audience.

Thorne's book, "Black Holes and Time Warps: Einstein's Outrageous Legacy" (W. W. Norton & Company, 1994), touches on many of the same subjects discussed in his more recent book, "The Science of Interstellar" (W.W. Norton & Company, 2014), including the possibility of interstellar travel through wormholes and the potential for time dilation around black holes. Two decades later, Thorne's first book remains a premier resource on the subject.

"I actually hadn't realized it was the anniversary, because I've been so swallowed up with 'Interstellar,'" Thorne told Space.com. (Thorne is also a theoretical physicist at the California Institute of Technology.) "I do wish that I had time to update the book. I hope to do so in the next few years."

When Thorne wrote "Black Holes and Time Warps" in the early '90s, he and other theorists believed that falling into a black hole resulted in death by a process called "spaghettification" or "the noodle effect," in which a person would be stretched and squeezed until his or her body resembled a very long string of pasta. [Time Travel and Wormholes: Kip Thorne's Wildest Theories ]

"When you fall into a black hole, everything that falls in after you over millions of years, as seen by you inside the black hole, comes pounding down on you in a fraction of a second, because of the enormous differences of time flow," Thorne explained. This would create a singularity: a location where the laws of physics break down and measurements of gravity go to infinity. "That produces sort of a 'sheet singularity' descending on you at the speed of light."

"Stuff that fell into the black hole before you, some of it will backscatter back up toward you," said Thorne. This could happen with any and all of the material that had ever fallen into the black hole during its lifetime. The material would create a shockwave singularity coming straight up at you.

"In a similar way, in both theoretical and observational studies, we had only seen black holes when they're more or less quiescent," he said. "We'd not seen or learned much about how they behave when they collide. And their collisions create wild oscillations in the rate of flow of time and in the whirling motions of space, in complicated vortex-like or whirlpool-like behaviors. And in the last decade, particularly the last five years, thanks to supercomputer calculations, we've begun to learn about space-time when it is behaving like it's in a storm."

The Laser Interferometer Gravitational Wave Observatory, or LIGO, in Louisiana is currently undergoing upgrades to become Advanced LIGO, and Thorne says he's highly optimistic that the upgraded observatory will finally detect evidence of gravitational waves. That data, combined with theory, will further scientists' understanding of the warping of space-time.

Another subject high on Thorne's list of topics he'd like to discuss in an update of his book is an idea used in the movie "Interstellar": that the universe human beings see is embedded in a larger universe of a higher dimension. The visible universe (called the "brane," short for membrane) has three spatial dimensions and one time dimension; a fourth spatial dimension called the "bulk" may be all around people, but they can't perceive it. In the movie "Interstellar," the "bulk" is called "the fifth dimension."

Thorne mentioned specifically the work of physicists Lisa Randall at Harvard and Raman Sundrum at the University of Maryland, who have proposed that the bulk might be something scientists can detect through experiments. Randall discussed the details of this theory in the book "Warped Passages" (Harper Perennial, 2006).

Other experiments that don't involve a multi-billion-dollar machine have also searched for the "bulk," but so far those have turned up nothing. The theories currently don't give any specific indication of where a solution might be found.

"Black Holes and Time Warps" also touches on the history of black holes (they were first theorized in the 1930s, but astronomical searches didn't begin until the 1960s) and the politics surrounding the field. (Thorne was one of a group of physicists who fought hard to keep Russian and American scientists in contact during the Cold War.)

Thorne's book is not exactly light reading (the paperback is a hefty 527 pages), but that doesn't stop it from being a page-turner. It offers accessible explanations of the science responsible for black holes and other mind-boggling physical phenomena in the universe. Readers will find the occasional equation and lots of helpful images and diagrams. Anyone interested in learning more about the history and science of black holes should consider giving it a read.

All this is only natural, because weird things happen near black holes. For example, their gravity is so strong that they bend the fabric of the universe. Einstein explained this: The more massive something is, the more gravity it produces. Objects like stars and black holes do this so powerfully that they actually bend light and pull space and time with it. And it gets weirder: If you were closer to a black hole than I was, our perceptions of space and time would diverge. Relatively speaking, time would seem to be going faster for me.

Thorne Isn't your average astrophysicist. Sure, he's a famous theorist, but even before his retirement from Caltech in 2009 he was deeply interested in explaining the heady ideas of relativity to the general public. Just before his retirement, Thorne and film producer Lynda Obst, whom he'd known since Carl Sagan set them up on a blind date three decades earlier, were playing around with an idea for a movie that would involve the mysterious properties of black holes and wormholes.

And therein lies a problem. See, other stars are really far away. Reaching even the nearest ones would take decades at speeds we humans have no idea how to attain. Back in 1983, when Sagan needed a plausible solution to this problem for the story that would become the movie Contact, Thorne suggested the wormhole, a hypothetical tear in the universe connecting two distant points via dimensions beyond the four we experience as space and time. A wormhole was a natural choice for Interstellar too. As Thorne talked about the movie with Nolan, their discussions about the physical properties of wormholes led to an inevitable question for a filmmaker: How do you actually show one onscreen?

World-renowned astrophysicist Prof. Kip Thorne, theoretical physics, the California Institute of Technology, described how black holes and the recent detection of gravitational waves contributed to his work on Academy-Award winning film, Interstellar, at a lecture Wednesday.

Thorne helped produce Interstellar and co-found the Laser Interferometer Gravitational-Wave Observatory, which successfully detected gravitational waves for the first time in February, according to the University.

Among the pioneering physicists who've shed light on these dark objects is Kip Thorne, an emeritus professor at Caltech and architect of some of the leading cosmological theories of how black holes warp space and time. Thorne describes some of the latest thinking on black holes in a paper published in the Aug. 3 issue of the journal Science.

Kip Thorne: Yes, but mass is equivalent to energy, according to Einstein, and mass or energy can take many different forms. It can take the form of energy in a blowing wind, it can take the form, in this case, of mass or energy that is tied up in the curvature of space-time itself. [Photos: Black Holes of the Universe]

Thorne: The matter of which a star is made, the atoms of which a star is made, are destroyed at the center of a black hole, when the black hole is created. The matter is gone, but the mass, in the sense of mass and energy being equivalent, has gone into the warped space-time of the black hole.

Thorne: Each black hole spins on its axis like the Earth spins. That spin creates two vortexes of twisting space, somewhat like vortexes in a bathtub or a whirlpool. There's one vortex of twisting space that sticks out of the north pole of the black hole, and one vortex that sticks out of the south pole. That's one aspect of a black hole's warped space-time. There are others, but let's just talk about that one.

When two black holes orbit around each other and collide and merge, those vortexes then start sweeping around and around the merged black holes. They get deposited onto the surface, what we call the horizon, of the merged black holes, so you now have four of these vortexes on the horizon. And as the black hole turns, these vortexes sweep back like the spiral arms of a galaxy, or like water from a whirling sprinkler; they reach outward and backwards and they become these gravitational waves.

Thorne: We have very extensive observational evidence by now of black holes. The central dark object at the middle of our galaxy has been studied in beautiful observations [showing] bright stars that travel around the central object in orbits rather like the orbit of a comet. They swing in close to the object and then are thrown back out.

The object can be weighed and it seems to weigh between 3 and 4 million times what the sun weighs. It's not producing any light, but it does produce, in erratic ways over time, bursts of radio waves. This object is just like what we think a black hole should be.

So I think in the minds of astronomers now, there's no doubt. There certainly was doubt 10, 20, 30 years ago. But the observational data from electromagnetic observations have become so good, so impressive, that I don't think there's any doubt anymore.

3a8082e126