When warm weather returns and nights become milder, many take advantage of the clear skies to observe the stars. And often, we notice that they seem brighter and more numerous in summer than in winter. But is this just an impression or a scientific reality?
Illustration image Pixabay
The answer lies both in our atmosphere and in the position of the stars in the sky during this season. In summer, the air is generally warmer and drier, making it more stable and transparent. Starlight therefore passes through fewer layers of turbulent or humid air than in winter, giving us the impression that they twinkle less and shine more brightly.
Additionally, summer often offers clearer skies. Nights may be shorter, but they are also more conducive to observations as we spend more time outdoors and enjoy the night sky more easily.
But there is also an astronomical reason: the summer sky is particularly rich in bright stars. Constellations like Lyra (with Vega), Aquila (with Altair), and Cygnus contain some of the brightest stars visible to the naked eye.
The Milky Way is visible all year round, but it is in summer that we can see its densest and most spectacular part, which points toward the galactic center located in the direction of the Sagittarius constellation. Although this galactic center is higher in the sky from the southern hemisphere, it remains observable from the northern hemisphere, though lower on the horizon. This brighter part of the Milky Way contributes to the feeling of a richer and more dazzling sky in summer.
If stars appear brighter in summer, it is thanks to an atmosphere more favorable for observation and a celestial arrangement particularly generous with luminous stars. A true gift from nature that turns our summer evenings into a celestial canopy to behold.