When we look at the stars in the clear night sky we see how some stars they blink emitting, as if it were a lighthouse, an intermittent light; there are even others that seem to change color. Despite everything, the stars do not stop emitting light at any time.
All of this is an optical effect -atmospheric scintillation- produced by disturbances in the atmosphere, since, despite the fact that it is transparent, it is not uniform. The gases that make it up are at different temperatures, have different densities and are subject to turbulence, characteristics that prevent light from traveling in a straight line and being subjected to numerous refractions.
etymologically languages It derives from the Latin tilillare, which can be translated as tickle, and that is because, in a way, tilillar means moving a part of the body with a slight and rapid tremor, like the one we do when we are tickled.
Less in dry climates
The stars twinkle, therefore, because the atmosphere is not homogeneous, it undergoes pressure and temperature oscillations. This causes the air to move in a chaotic way, the warmer rising and mixing with the colder when the sun warms the earth’s surface.
The climate also influences the way in which we observe how the stars twinkle, when they are observed from places with a more humid climate the effect is greater, since the humidity makes the air denser and, therefore, the image be less sharp.
Tililar poses a real problem for astronomers, a phenomenon known as ‘seeing’ –vision-, which is why it is very important to properly choose the place where they should place their telescopes, favoring dry places and high altitudes.
Experts point out that the best observing conditions are obtained with a seeing diameter of less than 0.4 arcseconds and this is achieved in high-altitude observatories, such as Mauna Kea, in Hawaii.
The sun doesn’t shine
The seeing phenomenon It also happens the other way around, if we travel by plane we can see how the streetlights, headlights and lights of towns and cities blink, even though we are a few kilometers away.
Planets generally shine brighter than stars because they are closer to us, so the thick beam of light they reflect is less affected by atmospheric refraction and therefore does not flicker.
If we look at the night sky and see an object that does not blink, it is probably Mars, Venus, Mercury or Jupiter. By the way, the stars do not twinkle from Mars, since the red planet has an atmosphere about a hundred times thinner than that of our planet.