One of the astronomical puzzles over which scientists have been debating for more than one millennium is why it is always dark in space.
Well-known specialist Thomas Diggs, whose years of life dates back to the 16th century, argued that the Universe is immortal and infinite, there are many stars in its spaces, new ones regularly appear. But according to this theory, at any time of the day the sky should be dazzlingly bright from their light. But in reality, everything is quite the opposite: during the day everything is illuminated by one sun, and at night the sky is dark, with dots of stars barely visible to the naked eye. Why is this happening?
Why can't the sun illuminate space?
Anyone can see the sun, which illuminates the entire sky and surrounding objects of reality during the day. But if we could just soar up a few thousand kilometers up, we would notice an ever-thickening darkness and bright flashes of distant stars. And here a completely logical question arises: if the Sun is shining, why is it dark in space?
Experienced physicists have long found the answer to this question. The whole secret is that the Earth is surrounded by an atmosphere filled with oxygen molecules. They reflect sunlight directed toward them, acting like billions of miniature mirrors. A similar effect creates the impression of a blue sky above your head.
There is too little oxygen in outer space to reflect light even from the closest source, so no matter how much the Sun shines, it will be surrounded by a frightening black haze.
The Olbers Paradox
Diggs reflected on the sky, covered in an infinite number of stars. He was confident in his theory, but he was bewildered by one thing: if there are many stars in the sky that never end, then it should be very bright at any time of the day or night. In any place where the human eye falls, there must be another star, but everything happens exactly the opposite. He did not understand this.
After his death, this was temporarily forgotten. In the XIX century, during the life of astronomer Wilhelm Olbers, this riddle was again remembered. He was so excited about this problem that the question of why it is dark in space when stars shine was called the Olbers paradox. He found several possible answers to this question, but in the end he dwelled on the version that spoke of dust in outer space, which dense the light of most stars with a dense cloud, so they are not visible from the surface of the Earth.
After the death of the astronomer, scientists learned that powerful radiations of energy depart from the surface of stars, which can heat the temperature of the surrounding dust to such an extent that it begins to glow. That is, clouds cannot interfere with starlight. The Olbers paradox received a second life.
Outer space researchers tried to study it, offering other options for answering a burning question. The most popular version was the dependence of starlight on the location of its carrier: the farther the star, the weaker the radiation from it. This option was not continued, since there are an infinite number of stars, there should be enough light from them.
But every night the sky darkens. Another generation of astronomers proved that Diggs and Olbers were mistaken in their assumptions. Edward Harrison, a well-known researcher of space phenomena, became the creator of the book "Night Darkness: The Enigma of the Universe." He laid down in it another theory, which is adhered to to this day. If you believe her, then the stars are not enough to constantly illuminate the night sky. In fact, their limited number, they tend to end, like our Universe.
An infinite number of stars - myth or reality?
There is a mathematical theorem: if you look at a substance with a non-zero density, which is located in unlimited space, then in any case it can be seen after a certain distance. In the case when the cosmos is infinite and filled with stars, a look directed in any direction should see another star.
From the same theorem, we can conclude that the light from the stars will be directed in all directions and will reach the earth's surface, regardless of their location. That is, a limitless Universe filled with constantly sparkling stars would have a bright sky at any time of the day.
The role of the big bang
At first glance, it seems that such a theory does not find confirmation in real life. Man cannot see all galaxies from the earth's surface, even with the help of special devices. To confirm their existence, he had to go into space, moving away from his home planet at a certain distance.
But scientists have their own opinion, which is based on the Big Bang - it was after him that the formation of planets began. Yes, there are many galaxies and individual stars outside the Earth, but their light has not yet reached us, since not so much time has passed since the explosion from the astronomical point of view. From this it follows that the process of development of the Universe is not finished yet, and space processes can affect the distance between the planets, moving away the moment when their light will be visible from the earth's surface.
Astrophysicists believe that the reason for the Big Bang is that in the past the Universe had a higher temperature and density. After the explosion, the indicators began to fall, which allowed us to start the process of forming stars and galaxies, so today they are not surprised by the fact that it is dark and cold in space.
Telescope as a way to see the past of stars
Any observer on the earth's surface can see starlight. But few people know that the star sent us this light in the distant past.
For example, you can recall Andromeda. If you go to her from Earth, then the journey will take 2,300,000 light years. This means that the light that it emits reaches our planet in this period of time. That is, we see this galaxy as it was two-plus million years ago. And if suddenly a catastrophe occurs in outer space that destroys it, then we will know about it after the same period of time. By the way, the light of the Sun reaches the surface of the earth 8 minutes after the start of the journey.
The modern technology development process has affected telescopes, making it possible to make them more powerful than the first specimens. Thanks to this property, people see light from the stars, which began to go to the Earth almost a dozen billion years ago. If we recall the age of the Universe, which is 15 billion years, then the figure makes an indelible impression.
The true color of space
Only a narrow circle of specialists knows that with the help of electromagnetic devices you can see completely different shades of space. All celestial bodies and astronomical phenomena, including flashes of supernovae and the moments of impact of clouds of gas and dust against each other, emit bright waves that special devices can catch. Our eyes are not adapted for such actions, so people wonder why it is dark in space.
If you give people the opportunity to see the electromagnetic background of the environment, then they would see that even the dark sky is very bright and rich in colors - in fact, there is no black space anywhere. The paradox is that in this case, mankind would not have the desire to explore outer space, and modern knowledge of planets and distant galaxies would have remained unexplored.