The Sun is just one of many stars in the universe, holding mysteries waiting for humans to explore.
Brightness
Every star visible to the naked eye in the sky is much larger and brighter than the Sun. Among the 50 brightest stars visible to the naked eye on Earth, the faintest one is Alpha Centauri. However, it is still 1.5 times brighter than the Sun and not easily visible in the northern hemisphere.
Number of Stars Visible at Night
On nights with no moon or any other light sources, a person with good eyesight can see about 2,000 – 2,500 stars at the same time. So, when someone claims to see millions of stars in the sky, it’s just an exaggeration.
Colors
In reality, stars change colors as their temperatures change. Red represents the lowest temperature at which a star can emit visible light. Hotter stars emit white light, and the hottest stars appear blue.
Stars Are Black Objects
A black object is something that absorbs 100% of all electromagnetic radiation (light, radio waves, etc.) when it strikes it. In the case of stars, they absorb all the incoming electromagnetic radiation while simultaneously emitting more radiation into space than they absorb. Hence, they are black objects that emit intense light. A perfect example of this is a black hole, though it appears truly black and doesn’t emit light.
No Green Stars
Astronomers don’t observe green stars, except for optical effects due to telescopes or the observer’s vision and contrast. Stars emit a spectrum that includes green light, but the human eye-brain connection rarely creates green stars. They usually get mixed with other colors, and stars appear white. The most common sequence of colors, from lowest to highest temperature, is red, orange, yellow, white, and blue.
The Color of the Sun
The Sun’s surface has a temperature exceeding 5,800 degrees Celsius, corresponding to a wavelength in the green range (around 500 nanometers). However, when humans observe colors, the Sun appears in white or even slightly yellow.
The Sun Is a Dwarf Star
Stars that create energy through the fusion and synthesis of hydrogen include dwarf stars, giant stars, and supergiant stars. Giant and supergiant stars represent the final stages of a star’s life, while most stars with smaller sizes are in a mature evolutionary stage called dwarf stars. The Sun is a dwarf star, and it is sometimes referred to as a “yellow dwarf.”
Stars Don’t Twinkle
Stars may appear to twinkle, especially when they are near the horizon. When light from a star passes through Earth’s turbulent atmosphere, it goes through various layers of air, causing changes in color and brightness, making stars appear to twinkle. This phenomenon doesn’t occur when we observe stars above the Earth’s atmosphere.
Distance
On a clear night, we can see Deneb, a star in the Cygnus constellation, which is about 32 quadrillion kilometers away. This is the easiest star to see in the night sky during the fall and winter in the northern hemisphere.