The weird interwoven world of general relativity

Let's get this straight right away: I don't really understand general relativity. 

I've read a lot of explanations about it. Briefly I'll feel like I grasp what general relativity is all about in a non-mathematical sense. 

A few days later, or even sooner, that understanding has slipped away and I'm basically as clueless as I was before. Which is strange, because usually I can conceptually grasp scientific truths much more fully. 

So there's something weird for me about general relativity. Which probably is best explained by the fact that almost everybody feels the same way. 

Spend two minutes watching this video of Neil deGrasse Tyson trying to explain gravity, which is the centerpiece of Einstein's theory of general relativity. Even Tyson starts off his explanation in a quizzical fashion.

 

Now, while Tyson says that Einstein said the following, actually it was theoretical physicist John Archibald Wheeler.

Spacetime tells matter how to move;
Matter tells spacetime how to curve.

It doesn't matter who was the source of this quote. As Tyson's interviewer says, that's poetic. It's my favorite explanation of general relativity, because I can grasp these two sentences even as I don't understand them.

A recent special issue of Scientific American is devoted to "100 Years of General Relativity." Here's a passage from one of the articles in the issue that says much the same thing.

Einstein's goal as he pursued his general theory of relativity was to find the mathematical equations describing two interwoven processes: how a gravitational field acts on matter, telling it how to move, and how matter generates gravitational fields in spacetime, telling spacetime how to curve.

So even though I don't begin to grasp the mathematics of general relativity, I have an, um, general conceptual feeling for it -- at least as it pertains to gravity.

It's that word, "interwoven," that seems key here. We're used to hierarchies, since human life and culture is full of them. This rules that. This causes that. This is above that. 

Yet nature rarely, if ever, works that way.

Like gravity in general relativity, this causes that and that causes this. Interwoven loops abound. Nature is much more of a circle than a straight line. Everything is interconnected, even though we humans do our best to break things apart and view them as discrete entities.

This is one reason why the concept of God no longer appeals to me. Like most religiously-minded people, I used to look upon God as The Big Man Upstairs, the cosmos' CEO who occupies the coolest office on the top floor. 

But this doesn't mesh with either common sense or scientific understanding.

For example, if God created the cosmos and now rules over it, who or what created God? If the supposed answer is no one, because God has always existed, then why can't the cosmos always have existed without a God?

An interwoven cosmos, or universe, seems considerably more likely than a hierarchical one. I've talked about this sort of thing before in posts such as:

"No beginning, no end. The universe simply is."
"Enlightenment made simple: it's reality."
"Relationship is the essential nature of reality."

I'm obviously not capable of capturing the essence of the cosmos in a few pithy sentences, as Wheeler did with gravity. About the best I can do is...

The universe causes me to do things; the things I do change the universe.

Comments

[Georgy Porgy]

So if everything is interwoven in that diagram and all things are equal or just things, and not a hierarchy, where we label some things as more important then others - how does sant mat arrive at its categorisation of dietary beliefs? It's okay to eat an carrot but not a fish or an egg.

[Nietzsche]

It becomes simpler to understand when you think of space time as aether.
https://www.youtube.com/watch?v=yH9vAIdMqng

The very fundament of relativity is length contraction. When light travels in moving water is does not accelerate as much as expected. So the water drags the aether that carries light partially or the length of the aether gets shorter. Einstein chose the latter option but did not say empty space got shorter. Thereby he introduced a new understanding of the aether and gravity. Now somehow matter is aether and it influences aether too. So everything is aether and matter might be a bubble in the aether. He are we a bubble in the ocean? :)

[tucson]

Astronomer Bob Berman at IdeaFestival 2015:

"What do we know about the universe?" asked astronomer Bob Berman to a crowded room at IdeaFestival 2015 in Louisville, Kentucky. "Why aren't the answers satisfying? Where do they go wrong?"

There's a lot of hard and fast data, he says, but it doesn't always give us the right answers. "It's important to know when science is working," said Berman, "and when it's not."

Berman offered four reasons that our scientific approach to understanding the universe doesn't work, and what we can do about it:

1. Limited data--Most of the universe is dark energy and the rest is dark matter--and we don't know what that is, said Berman. "We only know what's in our vicinity."

2. Limits to our dualistic logic system--There are two ways we get information, Berman said. Directly and indirectly. In science, the indirect method can work sometimes. But not for everything. "Unless you experience love," Berman said, "you won't know what it is. If you're blind, you won't know the color blue. You need experience. And when it comes to the universe, we run out of symbols." The universe is growing larger, he said, "but what does that mean? We can't picture infinity."

3. Space/time framework--"Space actually is not real," said Berman. "We all have an image of space and time, a framework, but when we look, that space and time may have a questionable reality." Of time, Berman said it's also not real. It's merely "an ordering system that we animals created. And it changes."

4. Consciousness--"Consciousness is the greatest unsolved problem in all of science," said Berman. "In every experiment, we're seeing, thinking, concluding--and it happens in our consciousness. Experiments go differently if we measure them and how we measure them. Where we measure makes a difference. It depends on us as observers." And while we "continue to study the brain and how it works, this doesn't answer the question of human experience," said Berman.

Berman believes that science is not approaching the universe from the right angle. We continue to study the Big Bang, he said, but it "doesn't compute with us. In our everyday lives we don't see puppies and lawn furniture popping out of nothingness. A universe out of nothingness? How could that be? How could we possibly know what things were like before the universe was the size of a grapenut?" And even if we pin down the Big Bang, we still can't comprehend the infiniteness of the universe, he said. "We are representatives of the universe. We have the universe inside of us."

"We are representatives of the universe. We have the universe inside of us." Bob Berman

"We're working on the assumption that studying the parts will give us the whole," Berman said. "That may not be true."

So what's the answer? "If our thought process doesn't work with the macro-universe," Berman said, "the answers don't make sense. It means we're asking the wrong questions."

In terms of what we can ever know about the universe, "we're not really making progress," Berman said. "We're not knowing more and more."

The secret, he said, might lie in recognizing that the thing we are looking for is obvious rather than hidden; present rather than absent.