Shulou(Shulou.com)11/24 Report--

"The universe is really modest, obviously has everything, but says it is in space. "How empty is the universe?

When we think of the emptiness of the universe, we may picture eight planets orbiting the sun in space, surrounded by vast interstellar space.

In fact, the universe is much more empty than we think. Take the Earth-Moon system, for example. Many people imagine that the Moon is like a minion circling the Earth.

But in fact, the average distance from the moon to the earth is more than 380,000 kilometers, 30 times the diameter of the earth, even if the eight planets line up station is not a problem.

This is only a small Earth-Moon system, which can even be simplified to a point for the Earth's orbit around the Sun. For this "point," the distance between the nearest "point" and it is 100 times the distance between the earth and the moon. There is Venus, the nearest planet besides Earth, and its orbit.

100 times the distance between Earth and the moon, or nearly 40 million kilometers, it's the closest planet. The nearest star, the Earth, is 150 million kilometers from the Sun, a distance also known as 1 astronomical unit (AU).

Mercury and Venus are the only two tiny dots in this astronomical unit of space. Even within 1.5 AU of the inner Solar System, there are only seven objects, including Earth, Mars, and their moons.

However, as the eight planets, the orbits of water, gold, earth and fire were already very close. For the gaseous planets in the outer solar system, the distances between them are even more exaggerated.

Jupiter orbits Saturn at an average distance of 4.3 astronomical units, which is almost the width of three inner solar systems. Saturn orbits Uranus, Uranus, and Neptune at distances of 10 AU.

So, is space a lot more empty than you think?

Also different is the asteroid belt between Mars and Jupiter. Do you imagine the asteroid belt to be a region of debris? How do you dodge when a spacecraft passes through it?

Indeed, the asteroid belt is considered to be the most densely populated region of the solar system. There could be hundreds of thousands, or even millions, of asteroids here (discovered plus undiscovered). But even so, the celestial bodies here are not as densely packed as everyone thinks, because this area is really too large.

The asteroid belt is nearly 1.5 astronomical units wide, roughly the width of the entire inner solar system. Add to that its radius of about three astronomical units, and you can imagine how big this annular region is. Think about what a million celestial bodies are in such a large space. The distance between the two celestial bodies is at least equal to the distance from the Earth to the Moon. So, the emptiness of the asteroid belt makes it difficult for spacecraft passing through it to collide.

So, does this view of the structure of the solar system look different than you thought?

However, the asteroid belt and the region where the eight planets are located are only a small part of the entire solar system, but this is already the most densely populated region in the solar system. If we take the Oort Cloud as the boundary, all of these things add up to just a point. Because the radius of the Oort cloud can reach tens of thousands of astronomical units, it is almost measured in "light years."

That is, it takes about a year for the sun's light to pass through the solar system's gate, and more than four years for it to shine on its nearest neighbor star, Proxima Centauri. Within this 4-light-year range, there are no other celestial bodies except for some wandering interstellar bodies like Omomo.

This distance of 4 light-years is also roughly the average density of stars in the Milky Way galaxy around the solar system. That is, within 4 to 5 light-years of a star, there is almost no second star.

How small is this density? If this space were reduced to the size of Earth, the only star here would be about the size of a football.

So even the densest star clusters in the galaxy, such as near the nucleus at the center of the galaxy or in globular clusters, are just a few hundred more "footballs," making no difference on the macro scale.

However, this is only interstellar space in the Milky Way. Compared to the intergalactic space outside the Milky Way, the density of interstellar space is already very high.

Out of the Milky Way, to reach other galaxies, usually in 100,000 or even millions of light-years to measure. For example, Andromeda, the Milky Way's nearest large galactic neighbor, is more than 2 million light-years away.

Of course, there are also dwarf galaxies such as satellites in between. However, even if these dwarf galaxies were included, there would only be dozens of galaxies within a range of 10 million light-years. Other than that, there was nothing else.

However, the space we are in is already considered a region with relatively dense galaxies.

Globally, there are apparently empty regions between the fibers in the large-scale fibrous structures connected by galaxies and galaxy clusters. These so-called "hollows" may be the real empty places in the universe.

For example, the famous Boötis void, in which only a few dozen galaxies have been found so far, is 250 million light-years across. The supervoid in the constellation Canis Centauri is even more exaggerated, reaching a diameter of 1 billion to 1.3 billion light-years. Alien civilizations living here would probably think that the universe was only so big if they were not good at astronomy.

Of course, such holes are the exception, and there are plenty of other places in the universe where matter is concentrated, like the Great Wall of galaxies. So if you break up all this stuff in the universe and spread it out evenly, guess how much stuff there is in every cubic meter of the universe?

The answer is: there are only six hydrogen atoms! This was equivalent to having only one grain of sand in a space as large as Earth!

But if you look at these atoms microscopically, you'll see that they're just as empty. Because besides the nucleus and the electrons outside the nucleus, 99.9999…% of the space in the atom is empty. If an atom were a football field, its nucleus and electrons would add up to no more than the size of a ping-pong ball. Thus, the emptiness of the universe is embodied not only on the macroscopic astronomical scale, but also on the microscopic quantum scale.

Although the universe is empty beyond imagination, this void may not be silent. On the contrary, it may be full of invisible noise such as quantum fluctuations. Perhaps the "emptiness" of the universe is not an absence, but another existence, which tells us that what we see may be only the tip of the iceberg, and that there are more mysteries waiting for us to discover.

This article comes from Weixin Official Accounts: Linvo Says Universe (ID: linvo001), Author: Linvo

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