The famous Einstein's General Theory of Relativity (GTR) this year marks 100 years and it is still the fundamentals of physics and astronomy. This theory, Einstein published in 1915, and she lay a cornerstone in understanding the scientific basis of the origin and evolution of the universe . Until now, it has inspired scientists around the world to find answers to the most interesting questions in physics and astronomy, which remain unanswered ...

The key idea of ​​general relativity is that space and time, that seem to be different things, really intertwined. Space has three dimensions: length, width and height. Time is the fourth dimension. All four are connected in the form of a giant cosmic cell. If you ever heard the phrase "space-time continuum," it is about him, and it is.
Roger Blandford of the Institute for Particle Astrophysics and Cosmology at Stanford University, Kavli said:

General relativity is now, I think, is taken as the basis for describing the universe as a whole, that is the basis of cosmology; it describes black holes, neutron stars, small adjustments of the orbits of planets and satellites in our own solar system

The nature of gravity
General relativity adds gravity to the special theory of relativity, which Einstein published in 1905. Special relativity states that the laws of physics are the same for all stationary observers and that the speed of light does not change, even if the observer or the light source is moving.
Special relativity explains the relationship between energy and mass known equation E = mc2, where E - energy, m - mass, and c - the speed of light in vacuum (about 1.08 billion kilometers per hour). This theory also combines space and time into a four-dimensional space-time.

General relativity extends this last idea, explaining that matter bends space-time, just as a heavy ball creates a cavity on a soft surface. It is important to understand the nature and the monumental space has come to Einstein did not immediately; He came to him after ten years of hard work and heavy mental.

"He had to move forward. He proposed the idea, from which he subsequently refused. But continues to move forward - Gauvreau Blandford - He is not guided by mathematical ideas and mathematical techniques. The first led his physical intuition; This extremely powerful physical intuition served him very well in the past. "
General relativity describes gravity, not as an innate force acting on the object, and as a consequence of the curvature of space-time. (Imagine how the ball rolling on an inclined surface, created a ball lying on a soft bed).
It was a powerful and radical idea - and it became the subject of attention for a hundred years.
General relativity predicts that light will filter the curve path, skirting a massive object like a galaxy cluster, which will significantly affect the space-time.
This effect was observed experimentally astronomers; Moreover, astronomers use a "gravitational lens" for the study of distant light sources. In fact, on a smaller scale, this phenomenon is even helping to seek a planet outside our solar system. (Exoplanets can be discovered by the way their home stars bend the light from background objects).

Features of Mercury's orbit around the Sun as the general theory of relativity.
"It explains the anomalous precession of the perihelion of Mercury, or the rotation of the line joining the sun to the point of closest approach to the planet - Blandford wrote in an article Science. - Einstein used general relativity to explain a 10 per cent difference in the precession, linking it with the gravitational pull of the other planets, 43 arcseconds per century. "
Other types of observational data also helped to put the general theory of relativity on a firm footing, says Blandford.
"We tested it many, many times, in many different ways," - he says. - "I think it would be fair to say that there is no conclusive measurements or observations that could cast doubt on the general theory of relativity."
Dark Universe
General relativity also suggests that the vast majority of the universe is made up of things that people can not detect directly (at this stage), and sometimes even understand, writes David Spergel of Princeton University.
A careful study of the motion of light and matter in the universe showed that the "normal" matter itself can not explain the laws of space-time curvature. Indeed, observations show that only 5% of the Universe consists of the familiar atomic matter, while 25% is dark matter, and 70% - the dark energy.
Dark matter does not emit or absorb light, giving its presence only through gravitational effects. Dark energy, meanwhile, is a mysterious force that is associated with an empty space and is considered responsible for the accelerating expansion of the universe.
In 1917, Einstein introduced the term "cosmological constant" in the general theory of relativity as a repulsive force that counteracts gravity and keeps the universe in a static state (at the time it was the prevailing view of the nature of the universe). After Edwin Hubble observations in 1929 showed that our universe is in fact expanding, Einstein abandoned the cosmological constant, considering it "the biggest mistake" of his life.
But the constant was the prophecy, because today, astronomers try to understand the nature of dark energy, which is well suited to her role.
"Why is the expansion of the Universe is accelerating? The most likely option - the cosmological constant (or the equivalent energy of the vacuum of empty space) is driven by the cosmic acceleration "- says Spergel. - "Another option - to develop a scalar field fills the space (like the Higgs field or fields of inflation, which is rapidly expanding universe in the early days of her). Both of these features combines "dark energy."
"Since all the evidence of dark energy using equations of general relativity, it is believed that the new theory of gravity help explain the observations, - he adds. - Features include a modified theory of gravity with extra dimensions. "
Future
General relativity will continue to unite the efforts of physicists, cosmologists and astronomers for a long time in the future, according to Blandford.
For example, scientists will use the theory to gain a better understanding of black holes, neutron stars and other celestial bodies and phenomena. Scientists also will continue to probe the nature of dark energy and dark matter, trying to understand the universe in very large scale.
Finally, scientists are trying to combine general relativity with quantum mechanics, to marry a very large very small. This ambitious and long-awaited "theory of everything" still eludes physicists, but they think it is achievable.
The recently released film "Theory of Everything" tells the story of Stephen Hawking, who became world-famous physicist, contrary to what has been confined to a wheelchair since his youth. The film is basically about life Hawking and his relationship with his wife, but still finds little time to explain on what made his career Hawking.

Hawking among many physicists trying to come up with the "theory of everything", a unified theory that explains everything in our universe, will bring together all the theories and processes that bring together what is not possible. He follows in the footsteps of Albert Einstein, who was also tried, but was unable to develop such a theory.
Find theory of everything would be a stunning achievement, comprehension of all the weird and wonderful things in the universe. For decades, physicists said and continue to say that the theory is just around the corner. So, we are on the threshold of understanding the most?
At first glance, the theory all sounds like a difficult task. It should explain everything from Shakespeare to the human brain, all that is on earth and beyond, says John Barrow of Cambridge University in the UK. "It's a matter of the universe."
However Barrow thinks that finding a theory of everything "is possible." Because the "laws of nature are few and simple, symmetrical and there are only four fundamental forces." In a sense, we have to put aside the complexity of the world in which we live.

"The results of the laws - that we see around us - is infinitely more difficult," - says Barrow. But the rules behind them standing, can be simple.

In 1687, many scientists thought that the theory of everything is found ...

Insight Newton

English physicist Isaac Newton published a book in which he explained the movement of objects and the principle of gravity. "Mathematical Principles of Natural Philosophy" presented things in the world established by the place. The story goes that in the age of 23, Newton went into the garden and saw an apple fall from a tree. While the physics know that the earth somehow attracts objects by gravity. Newton developed this idea.
According to John Konduitta, assistant Newton at the sight of an apple falling to the ground, Newton got the idea that the gravitational force "was not limited to a certain distance from the ground, and extends much further than was usual." According Konduitta Newton wondered: why not as much to the Moon?
Inspired by their guesses, Newton developed the law of gravity, which works equally well with apples on the earth and the planets revolving around the sun. All these objects, despite their differences, are subject to the same laws.
"People thought that he explained everything that needs to be explained - says Barrow. - It was a great achievement. "
The problem is that Newton knew his work gaping holes.
For example, gravity does not explain how small objects are held together because this force is not so great. In addition, although Newton could not explain what was going on, he could not explain how it works. The theory was incomplete.
There was a problem, and more. Although Newton's laws explain the most common phenomena in the universe, in some cases, objects violating its laws. These situations were rare, and typically includes high speed or high gravity but they were.
One such situation was the orbit of Mercury, the nearest planet to the sun. Like any other planet Mercury orbits the sun. Newton's laws can be applied to calculate the motions of the planets, but Mercury did not want to play by the rules. What a strange, its orbit had no center. It became clear that the universal law of gravity was not so universal, and it is not a law at all.
More than two centuries later, Albert Einstein came to the rescue with his theory of relativity. Einstein's idea, which in 2015 marks 100 years, has provided a better understanding of gravity.

However, despite its success, the theory of relativity is not a theory of everything, like Newton's theory.
Like Newton's theory does not work for a truly massive objects, Einstein's theory does not work in the microscale. Once you start to consider atoms and anything less, matter begins to behave very strangely.
Quantum mechanics

Until the late 19th century, the atom was regarded as the smallest unit of matter. Born from the Greek word "atomos", meaning "indivisible" atom by definition should not have been broken down into smaller particles. But in the 1870s, scientists have discovered particles that are 2,000 times lighter atoms. Weighing beams of light in a vacuum tube, they found a very light particles with a negative charge. So opened the first subatomic particle: the electron. In the next half-century, scientists discovered that the atom is the compound nucleus, around which electrons scurrying. This core consists of two types of subatomic particles neutrons which have neutral charge, and protons, which are positively charged.
But this is not all. Since then, scientists have found ways to divide matter into smaller and smaller pieces, continuing to refine our understanding of the fundamental particles. By the 1960s, scientists have found dozens of elementary particles, making a long list of so-called particle zoo.
As far as we know, three components of the atom was the only fundamental particle electron. Neutrons and protons are divided into tiny quarks. These elementary particles are subject to an entirely different set of laws different from those which govern the trees, or the planet. And these new laws - which were much less predictable - physicists have spoiled the mood.
In quantum physics, the particles have no definite place: their location slightly blurred. As if each particle has a certain probability of being in a certain place. This means that the world is in its essence is fundamentally indeterminate place. Quantum mechanics, even difficult to understand. As Richard Feynman once said, an expert in quantum mechanics,

"I think I can safely say that nobody understands quantum mechanics."

Einstein, too, was concerned about the vagueness of quantum mechanics. Despite the fact that he did, in fact, partly invented by Einstein himself never believed in the quantum theory. But in his palace - large and small - the general theory of relativity and quantum mechanics proved right to absolute power, being extremely accurate.
Quantum mechanics explains the structure and behavior of atoms, including why some of them are radioactive. It also forms the basis of modern electronics. You will not be able to read this article without it.
General relativity predicted the existence of black holes. These massive stars that collapse into themselves. Their gravitational pull is so strong that even light can not leave it.

The problem is that these two theories are incompatible, so can not be true simultaneously. General relativity says that the behavior of objects can be accurately predicted, whereas quantum mechanics says that you can only know the probability that the object will do. From this it follows that there are still some things that physics has not yet been described. Black holes, for example. They are massive enough to be applicable to them the theory of relativity, but also small enough to be able to apply quantum mechanics. If you do not find yourself close to the black hole, this incompatibility will not affect your daily life. But puzzling physicists most of the last century. Such incompatibility forces to search for a theory of everything.
Einstein spent much of his life trying to find such a theory. Not being a fan of randomness of quantum mechanics, he wanted to create a theory that unites gravity and the rest of physics to quantum strangeness remained a secondary consequence.

Its main task was to make gravity work with electromagnetism. In the 1800s, physicists discovered that electrically charged particles can attract or repel. For some metals attracted to the magnet. Obviously, if two kinds of forces that objects can have on each other, they may be attracted by the gravity and attracted or repelled by electromagnetism.
Einstein wanted to combine these two forces in the "unified field theory". To do this, he stretched space-time in five dimensions. Together with three spatial and one temporal dimension, he added a fifth dimension, to be so small and closed, we could not see him.
It did not work, and Einstein spent 30 years at the empty searches. He died in 1955 and his unified field theory has not been disclosed. But in the next decade there was a serious contender for this theory: string theory.
String theory

The idea is based on string theory is quite simple. Main ingredenty our world like the electron - is not a particle. This tiny loops or "strings". Simply because strings are very small, they seem to point.
Like the strings on a guitar, these loops are energized. Hence vibrate at different frequencies