Why is the universe dark and the solar system is also dark?

We live on the earth and see a colorful, beautiful, bright world during the day, that is, there is light around us, so why is it dark at night? On a night when there are no dark clouds, you can see countless stars. This is basically close to the truth of space, the truth of the solar system and the universe.

Because the sun is so close to us, countless sunlight enters the earth, and through the reflection of air molecules on the earth's surface and the reflection of various objects, the earth's surface is bright. We live in the air, the density of the air is very small and flowing, the brightness we see is actually a bright space, without air, we can't see the bright space, because the vacuum does not reflect the light, it can only be dark, on the moon because there is no air, there is no bright sky, [space], looking at the surface of the moon, there is reflection, looking at other places, it is dark. The air on the earth makes our daytime bright, the air plays a great role, scientists have found that there are seven colors of light, it is the seven colors of light mixed and reflected to form a special light [white light], we call such a day [day], the seven colors of light are red, orange, yellow, green, blue, indigo, purple.

Therefore, the sky without air is dark, basically like night, and the space of the solar system and the universe that leave the earth are dark because there is no reflection of air.

<> there is air on the surface of the earth.

There is no air on the surface of the moon.

Universe. The brightness of the earth is only a special case during the day, if there is no air buffer, strong sunlight will kill people, and you can't open your eyes, if you look away from the sun, the surroundings are dark, and you can only see a few stars.

The universe is just a huge space, a vacuum. If there's nothing in there, it's dark. With the sun, the stars shine brightly, and only then can we see the sparkling sunlight and stars.

If you light a torch in a house and light a torch in the field, you will find that in the room the whole room may be lit up, but if you are in the wild, you can't light the rest of the room at all.

The universe is dark, because the free electrons in the space of the universe reach enough to reach enough, so that there is no matter in the universe, similar to superconductivity, that is, the magnetic resistance of the universe is 0, so that whether it is the spectral electromagnetic waves generated by the sun or other electromagnetic waves in the universe, it cannot do work in the universe, or the work is 0, 0 naturally has no capital to convert light, so the space is black.

The universe is physically defined as all space and time (collectively referred to as space-time) and their connotations, including all forms of energy, such as electromagnetic radiation, ordinary matter, dark matter, dark energy, etc., of which ordinary matter includes planets, moons, stars, galaxies, galaxy clusters and intergalactic matter. The universe also includes physical laws that affect matter and energy, such as conservation laws, classical mechanics, relativity, etc.

What a great and insightful question! This is the absolutely correct answer: light and darkness are strictly human perceptions.

The only electromagnetic spectrum we have visible is only a small part of it. The vast majority of the electromagnetic spectrum cannot be observed with the naked eye, in other words, it is dark. If we do not see the visible part of the spectrum with our eyes here, it will be no different from any other part of the spectrum, it will be dark.

So the answer to your question is yes. Visible light is strictly contained in the human brain. The universe, without our eyes, is very dark.

But it's full of positive energy!

How many things are there in the universe?

In the context of your question, "thing" is a vague term – for example, there are all kinds of "things" – small, medium, large, extra-large, huge, and so on. However, since every "thing" in the universe is made up of atoms – I can tell you, there are in the observable universe 10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,00000000000000000,000,000,000,000,000,000,000,000,000,000,0

If you doubt it, you can count it yourself! :)

Why is the universe blackIn fact, many people have raised opinions on this issue before us, among which the 18th-century German astronomical Heinrich Olbers put forward the famous Olbers paradox, that is, if there are countless luminous stars in the universe, then the night sky where these stars are located should be bright. Olbers believes that there are still many dark places in the night sky because there are gases and dust in the universe, blocking light, resulting in a lot of light cannot reach the earth, but with the development of physics, this inference has been broken, because after the gas and dust absorb light, they will radiate out in the form of electromagnetic waves, resulting in a brighter universe. In addition to this, there is another theory, we all know that it takes time for light to travel, for example, the sun we see is the sun 8 minutes ago, and the universe is only 13.7 billion years old, that is to say, the farthest light we can see is emitted by stars 13.7 billion light-years away, but this is just a theory, because the universe has been expanding, and its expansion speed has exceeded the speed of light, so the light emitted by the stars that we say is 13.7 billion light-years away can only be on the road, We'll never see it.

That is, due to the expansion of space, so does the extent of our visible universe. The current visible radius of the universe is also greater than 13.7 billion light-years (46.6 billion light-years). As space expands, so does the scope of the universe we can see.

However, the universe beyond the borders is also moving away at a faster rate. Most of the universe will never be seen, and we will never be able to reach it. Due to the speed of light, we are trapped in a finite space with no way of knowing what the universe is like outside.

This is very much like the concept of a black hole horizon. In fact, this is also a kind of horizon, which is the opposite of a black hole. A black hole is a ray of light that never gets out, and our visible universe is a ray of light that never gets in.

In the visible universe, although light can reach the Earth, it is no longer visible light. The expansion of space stretches the wavelength of visible light, reducing the frequency accordingly. This phenomenon is called redshift, and the redshift of light is transformed into infrared rays or microwaves with lower frequencies.

It's not dark in space. In space, darkness and light coexist. Space is boundless, or the margins are so large that the stars in the universe do not emit enough light to illuminate the entire universe.

When all the stars in the universe are burned out, the universe no longer emits light and eventually becomes a black dwarf, and the sun is no exception.

The time required for the nuclear fusion reaction to be carried out inside the sun is very long, and the nuclear fusion reaction carried out in the interior of the sun has been carried out for 4.6 billion years so far, and the sun at this stage is in the middle age, and it will continue to carry out nuclear fusion steadily in the future, as long as 6 billion years, it will gradually enter the stage of old age, which is really unimaginable. The reason why the sun burns for so long is because there are so many raw materials; Moreover, the fusion collapse reaction area is small; At the same time, under the combined action of the sun's gravity and magnetic field, the energy inside the sun is released outward in a relatively stable square orange style.