Stars do not reflect light, as planets and their satellites do, but emit it. And evenly and constantly. And the blinking visible on Earth is possibly caused by the presence of various microparticles in space, which, falling into a light beam, interrupt it.
The brightest star, from the point of view of earthlings
From school, it is known that the Sun is a star. From our planet it is the brightest star, and by the standards of the Universe - a little less than the average in size and brightness. A huge number of stars are larger than the Sun, but they are much smaller.
Star graduation
Ancient Greek astronomers began to divide the heavenly bodies in size. By the concept of “magnitude” both then and now we mean the brightness of the star’s glow, and not its physical value.
Stars also vary in radiation length. According to the wave spectrum, and it is really diverse, astronomers can talk about the chemical composition of the body, temperature, and even remoteness.
Scientists argue
The debate over why the stars shine has been going on for decades. There is still no consensus. It is difficult to believe even for nuclear physicists that reactions occurring in a stellar body can release such a huge amount of energy, and without stopping.
The problem of thermonuclear fusion taking place in stars has occupied scientists for a very long time. Astronomers, physicists, chemists made attempts to find out what gives impetus to the eruption of thermal energy, which is accompanied by bright radiation.
Chemists believe that the light of a distant star is the result of an exothermic reaction. It ends with the release of a significant amount of heat. Physicists claim that chemical reactions cannot take place in the body of a star. For not one of them is able to go on non-stop for billions of years.
The answer to the question “why do stars shine” became a little closer after Mendeleev opened the table of elements. Now, a completely new way to consider chemical reactions. As a result of experiments, new radioactive elements were obtained, and the theory of radioactive decay becomes version number one in an endless debate about the glow of stars.
Modern hypothesis
The light of a distant star did not let Svante Arrhenius, a Swedish scientist, “fall asleep”. At the beginning of the last century, he turned over the idea of radiation by heat stars, developing the concept of electrolytic dissociation. She consisted of the following. The main source of energy in the star’s body - hydrogen atoms, constantly participating in chemical reactions with each other, form helium, which is much heavier than its predecessor. The transformation processes occur due to the gas pressure of high density and the temperature that is wild for our understanding (15,000,000 ° C).
The hypothesis has been enjoyed by many scientists. The conclusion was unequivocal: the stars in the night sky glow, because the synthesis reaction takes place inside and the energy released in this case is more than enough. It also became clear that the hydrogen compound can go on for many billions of years in a row.
So why do the stars shine? The energy that is released in the core is transferred to the outer gas shell and the radiation visible to us occurs. Today, scientists are almost certain that the "path" of the beam from the core to the shell takes more than a hundred thousand years. The ray from the star also goes long enough to the Earth. If the radiation from the Sun reaches the Earth in eight minutes, the brighter stars - Proxima Centauri - in almost five years, then the rest of the light can go for tens and hundreds of years.
Another “why”
Why stars emit light is now clear. Why is it flickering? The glow coming from the star is actually even. This is due to gravity, which pulls the gas pushed back by the star. The flickering of a star is a peculiar error. The human eye sees a star through several layers of air, which is in constant motion. A star ray passing through these layers seems to flicker.
Since the atmosphere is constantly moving, hot and cold air currents passing under each other form turbulences. This leads to a curvature of the light beam. The brightness of the stars also changes. The reason is the uneven concentration of the ray reaching us. The starry picture also shifts. The reason for this phenomenon is passing in the atmosphere, for example, gusts of wind.
Colorful stars
In cloudless weather, the night sky pleases the eye with bright multicolor. Saturated orange color in the stars of Aldebaran and Arcturus, but Antares and Betelgeuse are pale red. Sirius and Vega are milky white, with a blue tint - Regulus and Spica. Famous giants - Alpha Centauri and Capella - are juicy yellow.
Why do stars shine differently? The color of a star depends on its internal temperature. The “coldest” ones are red. On their surface is only 4,000 ° C. White-blue stars with surface heating up to 30,000 ° C are considered the hottest.
The astronauts say that in reality the stars are light evenly and brightly, and they only wink at earthlings ...