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 twinkling 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?
“Stars in the sky look like tiny little dots due to the fact that they are very far away. For example, the nearest star to us, Proxima Centauri, is about 4.2 light years away from Earth. That's 270,000 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.
A scientist explains that before light from stars can reach 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 in night sky, some stars seem to twinkle more than others due to several factors.
“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,” French says.
According to the scientist, the weather conditions at the time of stargazing also affect the twinkling effect. If the air is saturated with moisture, then it will be more dense, which means that the stars will seem to twinkle more strongly.
Why are telescopes placed in certain places on Earth?
Because of these factors, scientists choose more favorable positions in terms of stargazing, to place ground-based telescopes. 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 reduce 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 that cause the effect of flickering light, “says French.
Why the stars change color?
If you look closely at the night sky, then the brightest stars, such as Sirius, change their 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 that causes the color of the star to change as it flickers,” says French.
But there are “stars” in the sky that don't twinkle at all because they're actually planets in 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.< /p>
