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“Imagination is more important than knowledge.” ― Albert Einstein

Knowledge versus imagination. Einstein spent the latter part of his life pursuing a “single, all encompassing theory of the universe.”  He wanted to able to describe all of nature’s forces – to explain it all. He didn’t find it.

James Taylor sings in “Secret of Life

Now the thing about time
Is that time isn’t really real.
It’s just your point of view,
How does it feel for you?
Einstein said he
Could never understand it all.
Planets spinning through space,
The smile upon your face,
Welcome to the human race.

That Einstein quote at the top of this article continues “…for knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.” Imagination is often the pathway to increasing knowledge.

It is interesting that astronomy experiments now might test an idea of Einstein’s that he proposed almost exactly a century ago. It has been a longstanding question of why the Universe is expanding at an accelerated rate. Calculations in a new study could help to explain whether dark energy, as required by Einstein’s theory of general relativity, or a revised theory of gravity are responsible.

Einstein wasn’t a big fan of a lot of the physics that came at the end of his life, and would probably not be a fan of string theory.

Brian Greene is a professor of mathematics and physics at Columbia University who is probably best-known to the public for his NOVA television specials. He is one of the best “explainers” of this deep science. He explains string theory and I can understand it – until he stops explaining it and I have to tell someone else what he meant. The idea of minuscule filaments of energy vibrating in eleven dimensions that make up the “fabric of space.. and create every particle and force in the universe” is not easy to understand or accept.

String theory fills in the gaps of Newtonian physics, especially regarding how gravity works, and Einstein’s Unification Theory depends on the existence of extra dimensions, which contain these filaments and some string theorists posit that there are at least eleven dimensions. For all of us used to living in four dimensions, that is tough to imagine.

James Gates is known for work on supersymmetry, supergravity, and superstring theory. When he was asked about Einstein’s statement that “imagination is more important than knowledge,” he said“For a long time in my life, imagination was the world of play. It was reading about astronauts, and monsters, and traveling in galaxies, all of that kind of stuff, invaders from outer space on earth. That was all in the world of the imagination. On the other hand, reality is all about us. And it’s constraining, and it can be painful. But the knowledge we gain is critical for our species to survive.”

 


Brain Greene on string theory

Black hole Cygnus X-1

Black hole Cygnus X-1

There were headlines this year about the discovery of gravitational waves. Gravitational waves are ripples in the curvature of spacetime. They propagate as waves, in the way we are used to seeing the rings propagate from the stone thrown into the water traveling outward from their source.

In the old physics of Isaac Newton, gravitational waves cannot exist – something to do with physical interactions propagating at infinite speed. But then in 1916, Mr. Einstein’s theory of general relativity said that gravitational waves transport energy as gravitational radiation, a form of radiant energy similar to electromagnetic radiation.

In the book Black Hole Blues and Other Songs from Outer Space, Janna Levin writes about them and the quest to record the soundtrack of our universe.

I like Levin’s scientific writing that a non-scientist can enjoy and understand. She is a theoretical astrophysicist and professor of physics and astronomy at Barnard College of Columbia University. I have read two of her earlier books, How the Universe Got Its Spots and, one of my favorites, A Madman Dreams of Turing Machines.

She writes about those dark black holes that science-fiction loves to use. These holes – so odd to think of nothing as something – sometimes collide. Those unilluminated collisions produce energy more powerful than any since the origin of the universe. The energy emanates as waves.

We can’t see these events. No telescope will ever record a collision. The evidence would be the sound of spacetime ringing.

Einstein predicted gravitational waves as part of his theory of curved spacetime. It has taken us a century to begin recording the first sounds of it from space.

I think this unseen aspect is rather wonderful, as in full of wonder.  How strange to think that telescopes cannot see events earlier than about 380,000 years after the Big Bang, when the universe became transparent.

There are other theories.  One is that it the gravitational influences of other universes.

Levin writes about 50 years of searching for these spacetime waves. The original searchers, Rai Weiss, Kip Thorne, and Ron Drever – have added hundreds of others and new massive instruments sensitive enough to detect a bit of sound from space.

Levin

In a conversation on edge.org, she says that:

“The effect of these gravitational waves is to squeeze and stretch space. If you were floating near these black holes, you would literally be squeezed and stretched. If you were close enough, you would feel the difference between the squeezing and stretching on your face or your feet. We’ve even conjectured that your eardrum could ring in response, like a resonant membrane, so that you would literally hear the wave, hear it even in the absence of a medium like air. Even though we think that empty space is silent, in these circumstances you would hear the black holes collide but you wouldn’t see them; it would happen in complete darkness. The two black holes would be completely dark, and your only evidence of their collision would be to hear the spacetime ringing.”

Can you imagine two black holes colliding, curving space and time around them? They are orbiting each other, moving curves, moving black holes, maxing out that cosmic speed limit of light and sucking in time, space, even information.  I can imagine it, and yet not imagine it.

 

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