What is beyond the boundaries of the universe?

Astronomers previously believed that the universe was infinite, but Einstein's theory of general relativity showed that our universe does have a boundary, but this boundary lies in a higher dimension.

Before discussing the boundaries of the universe , we must first understand the boundaries in the universe, that is, from the Solar System to the Milky Way, then to the nearest Large and Small Magellanic Clouds in the Andromeda Galaxy 2.54 million light years away from us, these independent and closed celestial systems all have clear boundaries, the distance of a few light years between stars and the gap of millions of light years between galaxies have separated them very clearly.

However, in Einstein's view, since the space-time of the universe itself is three-dimensional space with time counted as an additional dimension, the entire universe is a closed four-dimensional hyperspherical structure on the macroscopic level. This means that if one were to pilot a spaceship at the speed of light in any direction, one would eventually return to the starting point. The spaceship pilot thinks he is going vertically upward, but in a closed universe, the geodesic itself is a closed curve and would return to the starting point before one even realizes it.

In traditional geometry, we often think of space as flat, but in fact, according to general relativity, space can actually be curved . This is because mass and energy change the space around it, causing it to curve. We often use Einstein's famous gravitational equation E = mc2 to describe this phenomenon, which is how the presence of mass and energy affects the properties of spacetime. Arguably, the curvature of space is the basis for the wonders of the universe. (Photo: Allthatsinteresting)

This finite universe model is actually similar to the human journey on Earth, both going straight ahead but eventually returning to the starting point. Similarly, if you want to see the whole Earth, you have to fly straight up from the Earth and into space, only in this way can you see the whole Earth and appreciate its limitations.

So if humans want to see the limits of the universe in the future, they must first open up a new direction or dimension in three-dimensional space, and then fly at the speed of light or super light speed in the new dimension, so that they can fly out of the world we are in.

In addition to its enormous scale, the mass in the universe is also unimaginable. Stars are the most basic building blocks of the universe, and they combine to form clusters, nebulae, and galaxies. However, the mass of stars is relatively insignificant. Scientists have discovered supernovae, giant flares of stellar explosions that release as much energy as all the stars in the entire galaxy combined. (Image: Allthatsinteresting).

According to the parallel universe theory, our current universe is just one of many parallel universes. There are countless universes in the vast hyperspace. Each universe is the product of a big bang. Different universe bubbles have different laws of the universe, such as our universe, the speed of light is 300,000 km/s, but the speed of light in other universes can be 30,000 or 300 km/s.

However, with current human technology, it is still too far to talk about the boundary of the universe, because even the Webb telescope - the most powerful telescope of humanity at present - cannot see the boundary of the universe but can only roughly guess its existence. The universe has a diameter of 93 billion light years , and at the present time, humans can only see 2 trillion galaxies in it and are also quite vague about the most macroscopic appearance of the universe.

The universe is a vast and mysterious existence, where there are countless wonders and unknowns, always confusing people in their exploration. With the advancement of technology and the development of scientific theories, we gradually realize that the universe may not only exist in the three-dimensional space we are familiar with, but also has the possibility of space curvature and parallel universes. (Photo: Allthatsinteresting).

In some science fiction movies, the Milky Way, 100,000 light years in diameter, is just a string of beads around a kitten's neck, and these beads are just marbles used by advanced alien civilizations to play games. Perhaps in the future we will discover that the entire universe is just a microscopic particle of a macroscopic object on a higher level.

In this case, our universe may be just a small part of a larger universe, like a Russian matryoshka doll, or the universe may be contained in a grain of sand, perhaps lying on the beach of an unimaginably vast world. Perhaps intelligent civilizations from other dimensions are now observing the Sun and Earth, just as we observe electrons and protons.

The universe remains the greatest mystery to human civilization, and the issues of its boundaries will certainly be discussed many times in the future. However, wherever the boundaries of the universe are, whatever lies behind it, human civilization has been born on Earth.