# What is space-time? Basic issues still need to be improved and developed

Beijing time on December 26, according tomedia reports, space-time (time-space) structure is a three-dimensional space and four-dimensional time combined concept model. According to the best physics theory available, space-time explains the unusual relativistic effects of objects as they approach the speed of light, as well as the motion of large objects in the universe.

Who found space-time?

The famous physicist Albert Einstein expanded the concept of space-time in his theory of relativity. Prior to his pioneering work, scientists used two different theories to explain physical phenomena, Newton’s laws of physics and James Clark Maxwell’s electromagnetic model, which described the motion of large mass objects, and James Clark Maxwell’ electromagnetic model, which explained the properties of light.

However, experiments conducted at the end of the 19th century showed that light has its own special features. Measurements show that light always travels at the same speed, no matter what happens. In 1898, Henri Poincare, a French physicist and mathematician, speculated that the speed of light could be an insurmountable limit. Around the same time, other researchers are also thinking about the likelihood that the size and mass of objects will change with speed.

Einstein proposed a special theory of relativity in 1905, bringing all these ideas together. Special relativity assumes that the speed of light is a constant, and to do so, space and time must be combined into a single frame to ensure that all observers see the same speed of light.

A person on an ultra-high-speed rocket will observe a slower flow of time and a shorter length of the object than a person who travels at a much slower speed. This is because space and time are relative, depending on the speed of the observer. Therefore, the speed of light is a more basic concept than the two.

The conclusion that space-time is a single structure is not Einstein himself. The idea came from the German mathematician Hermann Minkowski, who told an academic conference in 1908: “From now on, space or time alone is doomed to be hidden in the shadows, and only a combination of the two can sustain an independent reality.” “

The space-time he describes is still known as the time-space of the lyonowski, which is the computational background of relativity and quantum field theory. Astrophysicist and science writer Ethan Siegel says that in quantum field theory, the dynamics of subatomic particles are described as fields.

How does time and space work?

Nowadays, when people talk about space-time, they often describe it as like a rubber film. This also comes from Einstein, who realized in the course of developing general relativity that gravity is born because of bending in the structure of space-time.

Huge objects, such as the Earth, the sun, etc., distort in the air. These bends, in turn, limit the way all objects in the universe move, because objects must move along curved curvature. The motion caused by gravity is actually moving along curved space-time.

In 2011, NASA’s Gravity Probe B (GP-B) mission measured the shape of the vortex of space-time around the Earth and found it to be in line with Einstein’s prediction. But for most people, the bending of space-time structures is still difficult to understand. Although we can compare space-time to a rubber film, this analogy ultimately doesn’t hold water. The rubber film is two-dimensional, while space-time is four-dimensional. This film represents not only a distortion in space, but also a distortion of time. For physicists, the complex equations used to explain all this can also be tricky.

“Einstein built a beautiful machine, but he didn’t leave us a user manual,” wrote astrophysicist Paul Sutter. And by virtue of their ability to become a semi-legendary. “

Scientists don’t know yet.

Although relativity is complex, it is still the best theory for explaining the physical phenomena we know. However, scientists also know that the current model is still incomplete, because relativity is still not completely unified with quantum mechanics. Quantum mechanics explains the properties of subatomic particles very precisely, but does not contain gravity.

Quantum mechanics is based on the fact that the tiny particles that make up the universe are discrete, or quantum. So photons (the particles that make up light) appear in different ways, like small pieces of light.

Some theoretical physicists speculate that perhaps space-time itself exists in the form of these quantum blocks, which will help build the bridge between relativity and quantum mechanics. Researchers at the European Space Agency (ESA) have proposed the creation of the International Laboratory of Gamma-ray-Ray Astronomy for Quantum Exploration in Space-Time Space-Time, or GrailQuest, will travel around the Earth to make ultra-accurate measurements of gamma-ray storms in distant universes, further revealing the nature of space-time.

Such a mission would take at least 15 years to launch, but if successful, it could probably help scientists solve the biggest mystery in physics. (Any day)