How big is the universe?

How big is our universe? How did it get so big? First, the conclusion: The universe is getting bigger all the time. Using Einstein's general theory of RELATIVITY, it has a radius of about 46.5 billion light years, a diameter of 93 billion light years, and a lifetime of 13.8 billion years, taking into account the effects of cosmic expansion.

A lot of people look at this and they're kind of confused. 93 billion light years? What exactly is that? Let's start with the earth we know best. It takes about 12 hours to cross the Pacific by civil plane, and 18 days to go to the moon by it. The distance between the Earth and the sun is one astronomical unit, equivalent to 150 million kilometers, and it takes 8 minutes and 19 seconds for light to travel. It takes 20 years for a civilian plane, 82 years to travel to Jupiter, and 750 years to travel to Pluto, the ninth planet in the former solar system. The closest star to our solar system is Proxima Centauri, which is about 4.2 light years away and about 5 million years away by civilian plane.

Five million years is a long time for humans. And that's not even a fraction of the radius of the universe. So how did our universe get so big? And that comes from the original proposition -- the expansion of the universe.

The ever-expanding universe

Imagine a perfect ball of light, just a millimeter in size. It's the brightest, densest ball you can imagine, and if you think about squeezing the sun down to the size of an atom, it might help you imagine how dazzling the inside of this light ball is. No atom, or even the nucleus, could survive such a high temperature. They're all separated into elementary particles that make up plasma and photons, the energy quantum of light.

Now this ball of light is expanding faster than you can imagine, and within a second, it will be a thousand light years old. The change in the volume of the photosphere was not caused by an explosion, because no particle or even photon could have moved so fast. In fact, it's the space in the sphere that's expanding. As it expands, the wavelengths of the photons get stretched, they become less energetic, and the temperature of the plasma decreases. The first second after the universe expanded, the temperature was 10 billion degrees, and photons still had enough energy to destroy atomic nuclei.

As the space inside the sphere continues to expand. The plasma's temperature continues to cool, and particles of matter are already able to clump together to form nuclei. Ten minutes after the expansion begins, nuclei of the lightest chemical elements -- hydrogen, helium, lithium -- will have formed, and pronuclei of heavier elements like carbon, nitrogen, and oxygen will have formed in stars and supernovae.

The sphere continued to expand, but at a much slower rate. After 400,000 years, it has reached a size of 10 million light years. It was cold enough that nuclei could trap electrons and form the first atoms. Its environment is similar to the thousand-degree temperatures on the surface of the sun. Space is still expanding, but at a much lower rate, and it's still uniformly filled with plasma, which is basically characterized by matter and radiation. But when we look around the entire space, we can already see some small changes in density and temperature, although these are only relative changes of one in 100,000. Like waves in the ocean, these small waves of density appear at all scales from small to large.

As the universe expands, gravity makes these fluctuations stronger and stronger, much like an ocean wave approaching the shore. The denser regions become denser and collapse into galaxies, stars or planets. Less dense regions expand to fill the space between galaxies. Today, 13.8 billion years after the universe exploded, that millimeter-big ball of bright light has grown into a vast expanse of space with hundreds of billion galaxies and stars.

Even today, the expansion of the universe has not stopped

Human waiting, often hundreds of millions of years

As the universe expands to a larger size, the temperature decreases. The temperature of the universe is measured by the strength of electromagnetic waves. Electromagnetic wave is a kind of energy. Other energies include kinetic energy and potential energy of matter. The shorter the wavelength of electromagnetic waves, the higher the energy, such as gamma rays and X-rays. Conversely, long wavelength radio waves, such as microwaves and radio waves, have low energy. All energy can be expressed by temperature, high energy, high temperature; Low energy means low temperature.

When the universe was 376,000 years old, the primordial plasma oscillations stopped. The REASON FOR THE SUSPENSION IS THAT THE PROTON GRABS THE JOGGING ELECTRON, AND ALL OF a sudden THE amount OF ELECTRICITY IN THE universe goes TO zero, BECOMES neutral, AND THE PUSHING FORCE BETWEEN THE photon, electron AND PROTON disappears. In a modern laboratory, we can measure that at 3000K, the electron is slow enough for a proton to grab it with the force of positive and negative attraction.

In numerical terms, in the universe, we all measure the absolute temperature K (Kelvin). The boiling point of water is 373K and the freezing point is 273K; The surface temperature of the sun is 5777K. Electromagnetic microwaves, when the universe was 376,000 years old, with no electrons or protons to get in the way, began filling the universe with an energy of 3,000 K. After 13.8 billion years, as the universe expands, the electromagnetic waves are stretched and the temperature has dropped to 2.7250K. When the universe is small, the temperature is high. As the volume expands, the temperature decreases. It is the basic knowledge of thermodynamics that volume and temperature are inversely proportional.

The size of the universe has long been beyond the scope of human observation.

So, THE UNIVERSE HAS EXPANDED BY a factor of about 3000/2.7250=1100 since 376,000 YEARS AND over 13.8 billion years, roughly in line with the accurate RELATIvistic calculation of 1,292 times in the literature. The distance between galaxies, for example, the distance between the Milky Way and M61 in the Virgo cluster, which was as close as 40,000 light-years 13.6 billion years ago, is now more than 50 million light-years apart, and the distance is still increasing.

The universe expands endlessly. In the observation of the universe, the light source emits light energy in the direction of you, and at the same time, the expansion of space away from you; And your observatory, while it waits, moves in the opposite direction of the light source, and you wait for hundreds of millions of years.