There are fleeting ones, more or less bright and we can even distinguish them from planets by their light . However, if someone asks you, how would you define a star without saying “a bright point in the night sky?”
Stars are spheres of gas that is held together thanks to the balance between the gravitational force of the mass that makes it up and tends to group it together and the gas that tends to expand. Stars are highly energetic due to the nuclear reactions that take place inside them , of great power.
We can observe stars located millions of kilometers away thanks to this energy that they generate and that is emitted into outer space in the form of electromagnetic radiation ( light ), neutrinos ( ‘exotic’ particles ) and stellar wind ( gas ).
If you want to distinguish the brightness in the middle of the night from planets and stars, just analyze what the light you see is like: if it twinkles, it is a star . This flickering is due, as explained in the Spanish Astronomy Society, to the optical distortions produced by turbulence and the differences in density of the Earth’s atmosphere.
Stars have very different temperatures from each other. The coldest ones can reach surface temperatures of approximately 2000 ºC while the hottest can reach 50,000 ºC or can even become hotter.
The best known star is the Sun, whose surface temperature is around 6000 ºC, while its core reaches 15 million degrees.
