Our universe is much, much simpler than it sounds. Cash, a terrible word, or is everything much simpler than it seems? What exactly needs to be cached

31.07.2020

You will be surprised to hear that our universe is actually quite simple - it is our cosmological theories that turn out to be unnecessarily complex, says one of the world's leading theoretical physicists. Such a conclusion may seem illogical: in the end, in order to understand the true complexity of Nature, one has to think wider, study things on a smaller and smaller scale, add new variables to equations, invent "new" and "exotic" physics. Someday we will figure out what dark matter is, get an idea of where gravitational waves are hiding - if only our theoretical models become more developed and more ... complex.

This is not the case, says Neil Turok, director of the Perimeter Institute for Theoretical Physics in Ontario, Canada. According to Turok, if the universe, on the largest and smallest scales, tells us anything, it is about its incredible simplicity. But to fully understand this, we need a revolution in physics.

In an interview with Discovery, Turok noted that the major discoveries of recent decades have confirmed the structure of the Universe on cosmological and quantum scales.

“On a large scale, we mapped the entire sky - the cosmic microwave background - and measured the evolution of the universe, how it changed, how it expanded… and these discoveries show that the universe is startlingly simple,” he says. "In other words, you can describe the structure of the Universe, its geometry, the density of matter with just one number."

The most exciting takeaway from this reasoning is that describing the geometry of the universe with just one number is easier than describing numerically the simplest atom we know of, the hydrogen atom. The geometry of the hydrogen atom is described by three numbers that follow from the quantum characteristics of an electron in orbit around a proton.

“This tells us that the universe is smooth, but has a small level of fluctuation, which is described by this number. And that's all. The universe is the simplest thing we know. "

Somewhere on the opposite end of the scale, something similar happened when physicists explored the Higgs field using the most complex machine ever built by humans -. When physicists historically discovered the Higgs mediator particle - the Higgs boson in 2012 - it turned out to be the simplest type described by the Standard Model of particles.

“Nature uses the smallest solution, the smallest mechanism imaginable, to give particles their mass, their electrical charge, and so on," says Turok.

20th century physicists taught us that if you increase accuracy and delve deeper into the quantum world, you will discover a zoo of new particles. Because the experimental results produced a wealth of quantum information, theoretical models predicted more and more particles and forces. But now we have reached a crossroads where many of our advanced theoretical ideas about what lies “beyond” our current understanding of physics await some experimental results that will support predictions.

“We are in a strange situation where the Universe is talking to us; it tells us that it is extremely simple. At the same time, the theories that were popular (the last 100 years of physics) are becoming more complex, arbitrary and unpredictable, ”he says.

The Turk points to string theory, which has been billed as the "ultimate unification theory," packing all the secrets of the universe into a neat package. And also looking for evidence of inflation - the rapid expansion of the Universe that it experienced almost immediately after the Big Bang some 14 billion years ago - in the form of primordial gravitational waves etched into the cosmic microwave background, the "echo" of the Big Bang. But as we seek experimental evidence, we grasp at straws; experimental evidence simply does not agree with our unbearably complex theories.

Our cosmic origins

Turok's theoretical work is devoted to the origin of the universe, a topic that has received a lot of attention in recent months.

Last year, the BICEP2 collaboration, which uses a telescope at the South Pole to study the CMB, announced the detection of primary gravitational wave signals. This is a kind of "holy grail" of cosmology - the discovery of gravitational waves generated by the Big Bang can confirm inflationary theories of the Universe. But, unfortunately for the BICEP2 team, they announced the "discovery" even before the European Planck Space Telescope (which also maps the microwave background) showed that, not ancient gravitational waves.

What if the primordial gravitational waves never find it? Many theorists who have pinned their hopes on a Big Bang followed by a period of rapid inflation may be disappointed, but according to Turok, “this will be a powerful hint” that the Big Bang (in the classical sense) may not be the absolute beginning of the universe.

“The hardest thing for me is to describe the Big Bang itself mathematically,” adds Turok.

Perhaps a cyclical model of the evolution of the universe - when our universe collapses and starts over - would better fit observations. Such models do not need to produce primordial gravitational waves, and if these waves are not detected, perhaps our inflationary theories need to be improved.

Regarding the gravitational waves predicted to be produced by the rapid motion of massive objects in our modern universe, Turok is confident that we have reached such a degree of sensitivity that our detectors should soon detect them, confirming one of Einstein's predictions about spacetime. "We expect to see gravitational waves from colliding black holes in the next five years."

The next revolution?

From the largest scales to the smallest, the Universe appears to be “scaleless” - in other words, no matter what spatial or energy scale you look at, there is nothing “special” on the scale. And this conclusion speaks in favor of the fact that the Universe has a much simpler nature than modern theories suggest.

“This is a crisis, but a crisis at its best,” Turok says.

Thus, in order to explain the origin of the universe and come to terms with some of the most mysterious mysteries of our universe, like dark matter and dark energy, we may have to look at space in a completely different way. This will require a revolution in the understanding of physics, a revolutionary approach comparable in strength to Einstein's realization that space and time are two sides of the same coin, when general relativity was formed.

“We need a completely different view of fundamental physics. The time has come for radically new ideas, ”concludes Turok, noting that now is a great time for young people to study theoretical physics, since it is the next generation that is likely to revolutionize our understanding of the Universe.

On this thought, I was prompted by the results of a mini-analysis, which I conducted quite recently. I checked how much sql queries are spent on my blog, and on a pure WordPress, this is what happened

When generating the main page of my blog ( All modules on the blog are included) the script makes 19 requests. Wordpress has the same costs - 19 database queries

The numbers, of course, may not be accurate, but nevertheless I don't really like that the little-functional engine ( I'm talking about mine) is heavier, or on par with, much functional.

But what can you do? Getting rid of unnecessary requests by deleting them means completely killing the entire engine, isn't it?

What is php caching?

After my analysis, I started looking for a solution to this problem. There is a cure for this ailment, and it is called caching.

I did not name the note for nothing " Cash, a terrible word, or is everything much simpler than it seems?"because the word cache scares me with its incomprehensibility. No, I approximately know what a cache is, but on a subconscious level I think that not everything is as simple as it seems to me.

For accurate information, I naturally went to the Internet. I dug a little, and, as always, I found a sea of clever and incomprehensible words. I am now interested in the question, for whom are these abstruse texts written? It seems to me for those who are professionals in programming, namely for those who do not read the material of those who write them. Although I'm most likely like that too, a lot of clever words and it's not clear what's what ... However, I realized one thing.

Caching is nothing more than saving the result of a script to a separate file that is placed on the server. The next time a thread accesses the same page, the script will return the saved copy, and not go into the database for information, thereby reducing the number of SQL queries, which means increasing performance.

As, in principle, I thought. But it still seems to me that this information is incomplete or not correct.

When to update the cache file?

This is all very good, performance gains and the like, but there is one small problem. How do you tell the script that the page has changed, that is, when to update the saved file? All of the same clever and incomprehensible words, I found two options for creating a caching mechanism

Write an algorithm that will update the cache copy with a certain time interval.
Send some html headers, checking with their help the copy of the page with the copy of the page in the cache, and in case of different dates, update the cache

The first method seems to be more or less clear, but I have not figured out the second one. And most likely it would not have been possible to resort to this method, because, as I figured, in the case of comparing dates in headers, you will have to write special code that will update these dates in certain situations. And I'm too lazy to write such code =)

What exactly needs to be cached?

Before coming up with a mechanism for saving and updating files, I decided to think about what needs to be cached? I immediately refused to save the entire page as a whole, maybe this is the most economical way, but in this case absolutely all modules that are updated with each page restart will fail. Having thought, I decided that everything that is very fat will go to the cache ( too many requests) and everything that is updated every 100,500 years. There is such a possibility, since the engine consists of separate functions, the result of which, in most cases, is html code that can be saved to a file and sent to the server.

After some thought, I decided that I would send headers, meta tags and almost the entire sitebar to the cache ( except for the menu module) This is enough to shorten requests approximately doubled

My crooked way of caching pages

Why crooked? Because the way of recognizing outdated copies is too "not smart", I didn't think of a smarter way ...

Meta tags, titles and the module of read posts do not change very often, so their saved copies are updated once an hour. This is not difficult to achieve, there are plenty of examples on the Internet!

But the cache of the module for recent comments, polls and last posts is updated only when there are changes in the database. How do I identify change? Everything is very simple and not professional.

At the root of the blog is a text file containing a line like this:

My engine turns this line into an array. Each digit in the array is responsible for a specific module.

If it is zero, then the module cache is outdated and needs to be replaced
If there is one, then the cache is up-to-date and does not need to be updated.

Changes to this line are made when adding a post to the database, or adding a comment, thus the engine understands that the cache needs to be replaced. Isn't it a "crooked way" huh?

Nevertheless, requests on the home page dropped to 10, and on pages with notes to 9.

Achieved reduction of SQL queries in half, there is something to be happy about, if not counting the fact that an inadequate way of determining the life of files is used ...

In general, I end the monologue in the hope that the method is not so stupid ...

All the best! See you!

Life is much easier than it seems

Chapter 1. For a walk.

Let's go for a walk!
It is useful to take a walk in the evening.
Why can't you yet?
What other toothache?
Why do you need it? Get rid of her!
So, let's pull it out on the sly ...
Exactly…

She all flew out the window.
Well, let's go?
What's in the way?
Yes, for half an hour and we'll be back!
Put on something lighter! It's warm outside!
Evening? So what?
Wear whatever you want!
Well, the second is better!
That's all - I won't advise you anymore!

In my opinion, good!
Who cares what they think, you're not going to a dinner party!
Then take something simpler.
What is this complex?
No? Then push him out the door!
Go away!
Fine!
Are we ready to go?
Perfectly!
Yes, you look great!
Come on, I'll close the door ...

Chapter 2. Falling asleep ...

Are you comfortable?
What's wrong?
It's very convenient for me, but what have you got ...
Spread the sheet, bent over!
Better? Fine!
I wanted to tell you a story ...
What now?!
Something with a pillow? Take another ...
... so, the story is about how ...
Throw out this pillow !!!

Another thing.
You are listening to me?
This story is about two ...
Is it shining? What is shining?
A! Moon!
No, I will not get up, into the scrap ...
Get up you!
Just draw a better curtain.
Enough, it will go like this.
No more, lie down ...

Let's sleep.
What? I was going? What story?
Oh, exactly! I don’t remember already ...
Goodnight.

Chapter 3. Resting.

Will you have a cup of tea with me?
Okay, I'll cook it.
Here you are.
What are you worried about?
Trivia! Get it out of your head?
That's better!
Nice tea.
What haunts you?
Is this story so attached to you?
Of course, there are all kinds of people.
But to dwell on every word of every person ...
You can go crazy!
Listen to me: what was, what was.
Yes, just a tough day.
Let's talk better about something pleasant!
Very good tea ...

Chapter 4 One more walk.

How fresh it is outside!
Yes, the rain has passed.
Bumped on the roof all night.
It's always great to walk early on Sunday morning.
What are you saying? Afraid of freezing?
Ha! Get sick?
Yes, they do not get sick from this!
Caution - don't step into a puddle!
How will I get you out of there later?
What if it's deep there?
Not funny?
It's funny to me!
Ha ha! How can I present it!
(you flop down ...)
(I'm trying to get you ...)
(we wallow together in the mud ...)
(we are trying to resist her, but she is pulling us in ...)

A? What? Are you saying something?
Sorry, I was just thinking. Hee hee.
Smiling? Well, that means she was dreaming. Hee hee.
What rzhu? Look, the dog is funny!
So shaggy (hee hee).

Chapter 5. Shopping.

What will we buy?
I want a lot!
Yes, my belly already know how it asks?
This is still a normal stage.
Soon it will start to howl like that!
Do you remember the last time?
People were already rushing away - they thought wolves were roaming the city.
O! Let's take this?
What doesn't suit you this time?
Too high in calories?
Okay, let's take something else ...
So-so. What you need!
I will cook.
No problem.

What? What???
Are you afraid of poisoning?
I have not heard that this could be poisoned!
Well, you give it! You can think of it too!

And what is it?
This is the first time I've seen this.
Listen, put it back in place.
Don't touch anymore.
Everyone, let's go, I think dinner will be great!
???
I have enough money with me.
Don't even worry about it.

Chapter 6. The last, although you can go on for a long time ...

I'm back!
How delicious it smells!
(something is being prepared!)
What? Oh, it's all right.
All matters are settled.
We can safely go out of town tomorrow.
May the weather not deteriorate!
Well, even if it does go bad, we'll think of something!
What are you cooking?
I'm ready now!
Drooling is already flowing!
I'll go wash my hands.

How well prepared!
Very tasty, I like it!
What were the cases?
I went there, but something didn't work out.
And I thought - well, him! I was about to leave.
And it somehow resolved itself.
And there it immediately rolled like clockwork.
Yes, there were no problems ...

You will be surprised to hear that our universe is actually quite simple - it is our cosmological theories that turn out to be unnecessarily complex, says one of the leading physicists - theorists of the world. Such a conclusion may seem illogical: in the end, in order to understand the true complexity of nature, one has to think wider, study things on a smaller and smaller scale, add new variables to equations, come up with "New" and "exotic" physics
... Someday we will figure out what dark matter is, get an idea of where gravitational waves are hiding - if only our theoretical models become more developed and more ... complex.

This is not the case, says Neil Turk, director of the Institute for Theoretical Perimeter Physics in Ontario, Canada. According to the Turk, if the universe, on the largest and smallest scales, tells us anything, it is about its incredible simplicity. But to fully understand this, we need a revolution in physics.

In an interview with Discovery, the Turk noted that the largest discoveries of recent decades have confirmed the structure of the universe on a cosmological and quantum scale.

“On a large scale, we mapped the entire sky - the cosmic microwave background - and measured the evolution of the universe, how it changed, how it expanded ... and these discoveries show that the universe is amazingly simple,” he says. “In other words, you can describe the structure of the universe , its geometry, the density of matter with just one number. "

"This tells us that the universe is smooth, but has a small level of fluctuation, which is described by this number. That's all. The universe is the simplest thing we know."

Somewhere on the opposite end of the scale, something similar happened when physicists explored the Higgs field using the most complex machine ever built by humans, the Large Hadron Collider. When physicists historically discovered in 2012 the particle that mediates the Higgs field - the Higgs boson - it turned out to be the simplest type described by the Standard Model of particles.

"Nature Uses the Minimum Solution, the Minimal Mechanism that You Can Only Imagine, To Give Particles Their Mass, Their Electric Charge, And So On," says the Turk.

20th century physicists taught us that if you increase accuracy and delve deeper into the quantum world, you will discover a zoo of new particles. Because the experimental results produced a wealth of quantum information, theoretical models predicted more and more particles and forces. But now we have reached a crossroads where many of our advanced theoretical ideas about what lies “beyond” our current understanding, physicists are awaiting some experimental results that will support predictions.

"We find ourselves in a strange situation where the universe speaks to us; it tells us that it is extremely simple. At the same time, the theories that have been popular (the last 100 years of the development of physics) are becoming more complex, arbitrary and unpredictable." , he says.

The Turk points to string theory, which has been billed as the "Ultimate Unification Theory", packing all the secrets of the universe into a neat package. And also looking for evidence of inflation - the rapid expansion of the universe that it experienced almost immediately after the big bang some 14 billion years ago - in the form of primordial gravitational waves etched into the cosmic microwave background, the "echo" of the big bang. But as we seek experimental evidence, we grasp at straws; experimental evidence simply does not agree with our unbearably complex theories.

Our cosmic origin.
The Turk's theoretical work is devoted to the origin of the universe, a topic that has received a lot of attention in recent months.

Last year, the Bicep2 collaboration, which uses a telescope at the south pole to study the CMB, announced the detection of primary gravitational wave signals. This is a kind of "Holy Grail" of cosmology - the discovery of gravitational waves generated by the big bang may confirm inflationary theories of the universe. Unfortunately for the Bicep2 team, they announced "Discovery" even before the European Plank Space Telescope (which also maps the microwave background) showed that the Bicep2 signal was caused by dust in our galaxy, not ancient gravitational waves.

What if the primordial gravitational waves never find it? Many theorists who have pinned their hopes on a big bang followed by a period of rapid inflation may be disappointed, but in the words of the Turk, "this will be a powerful hint" that the big bang (in the classical sense) may not be the absolute beginning of the universe.

"The most difficult thing for Me is to Describe the Big Bang itself Mathematically," adds the Turk.

Regarding the gravitational waves predicted to be generated by the rapid motion of massive objects in our modern universe, the Turk is confident that we have reached such a degree of sensitivity that our detectors should soon detect them, confirming one of Einstein's predictions about space-time. "We Expect To See Gravitational Waves From Black Hole Collisions In The Next Five Years."

The next revolution?
From the largest to the smallest, the universe appears to be "Scaleless" - in other words, no matter what spatial or energetic scale you look at, there is nothing "special" about the scale. And this conclusion speaks in favor of the fact that the universe has a much simpler nature than modern theories suggest.

"This is a Crisis, but a Crisis at its Best," says the Turk.

Thus, in order to explain the origin of the universe and come to terms with some of the most mysterious mysteries of our universe, like dark matter and dark energy, we may have to look at space completely differently. This will require a revolution in the understanding of physics, a revolutionary approach comparable in strength to Einstein's realization that space and time are two sides of the same coin, when general relativity was formed.

“We need a completely different understanding of fundamental physics. It's time for radically new ideas,” concludes the Turk, noting that now is a great time for young people to study theoretical physics, since it is the next generation that will most likely turn our understanding of the universe upside down.