The researchers explained that stars have nothing to do with their twinkling.
If you look at the cloudless night sky, it seems that the stars twinkle. But why do they do it, and do they do it at all? What phenomenon causes observers on Earth to perceive their light as changing? English physicist Ryan French answered these questions in an article for Live science.
According to Ryan French of University College London, UK, the most accurate answer to the question “why do stars twinkle?” there will be the following wording – the stars do not actually twinkle. Stars have nothing to do with the flickering that we see in the night sky in cloudless weather. This twinkling is the result of how we see stars from Earth.
Why do stars twinkle?
“The stars in the sky look like tiny little dots because they are very far away. For example, the nearest star to us, Proxima Centauri, is located at a distance of about 4.2 light years from Earth. This is 270 thousand times farther than the distance from our planet to the sun, and the light from the stars has to travel a huge distance before we see it on Earth with our own eyes,” says French.
The scientist explains that before the light from the stars reaches our eyes, it must pass through the earth’s atmosphere. In it, light collides with different layers of oscillating air. It is these vibrations that cause the light to flicker. That is, it seems to us that the stars themselves twinkle.
“When you look at the stars from space, they don’t twinkle, the light doesn’t have any atmospheric interference,” says French.
Why do some stars twinkle more?
When we look up into the night sky, some stars appear to twinkle more than others. Several factors influence this.
“The more air that starlight has to overcome in Earth’s atmosphere, the more twinkling a star will appear. For example, those that we see close to the horizon may appear to be such strong twinkling stars,” says French.
According to the scientist, the effect of twinkling is also affected by weather conditions at the time of observing the stars. If the air is saturated with moisture, then it will be denser, which means it will seem that the stars twinkle more strongly.
Why are telescopes placed in certain places on Earth?
Because of these factors, scientists choose more favorable positions for ground-based telescopes in terms of stargazing. French says the largest and most powerful telescopes are in the mountains and where the air is not saturated with moisture. This makes it possible to shorten the distance that light travels from stars through the atmosphere to telescope mirrors and increases the efficiency of observations.
“The most ideal places for telescopes are the Atacama Desert in Chile (South America – ed. note) and the tops of volcanoes in Hawaii (located in the Pacific Ocean – ed. note) and the Canary Islands (located near Spain – ed. note). These telescopes the best ability to see the light of the stars. Where the air is dry and rarefied, in these places it is best to observe the stars. There are no strong fluctuations in the air, which cause the effect of flickering light, “French says.
Why do stars change color?
If you look closely at the night sky, then the brightest stars, such as Sirius, change color during the twinkling. This is due to the fact that the light from such bright stars is slightly refracted, that is, bent in the Earth’s atmosphere. And this leads to the fact that the color of the star changes during the twinkling,” says French.
But there are “stars” in the sky that do not twinkle at all, because these are actually the planets of the solar system. They’re much closer to us, and they just reflect light from the sun that doesn’t change as it passes through the atmosphere, French says.