Tähtiä

Tähtiä is the partitive plural form of the Finnish word tähti, meaning "stars." In Finnish, tähtiä is used when referring to an indefinite amount of stars or when the noun is the object of a verb requiring the partitive case. The term is commonly used in everyday language and in scientific contexts to discuss stars collectively.

In astronomy, a star is a luminous sphere of plasma held together by gravity and generating energy through nuclear fusion in its core. Hydrogen fuses into helium, releasing vast amounts of light and heat. Stars form from dense regions of interstellar gas within molecular clouds and evolve over millions to billions of years. Their evolution depends on initial mass: lower-mass stars settle on the main sequence for long periods, while more massive stars become red giants or supergiants and eventually end as white dwarfs, neutron stars, or black holes.

Observers distinguish stars by brightness and color. Apparent magnitude describes how bright a star appears from Earth, while absolute magnitude reflects intrinsic brightness at a standard distance. Distances to stars are measured in light-years or parsecs, often via parallax. Stars are classified by spectral types (O, B, A, F, G, K, M), which correlate with surface temperature and color and form the basis of the Hertzsprung-Russell diagram used to study stellar evolution.

Stars populate galaxies and are integral to their structure and history. The Sun is a typical G-type main-sequence star, serving as a reference for understanding other stars, including the many that make up the visible night sky. The Finnish term Tähtiä thus covers both linguistic usage and the vast astronomical phenomenon.