light year
the DISTANCE light travels in a year
so 'light year' is not a measure of time.
usually the space is measured in light years
Usually light-years, or parsecs.
The distance between two stars is typically much greater than the distance between two planets. Stars are usually light-years apart, while planets in the same star system are typically within a few astronomical units of each other.
They are not. A supernova is an explosion of a star. Blue stars usually end their lives in such explosions.
Those are called "planets". The ancient Greeks distinguished "fixed stars" - which is what we nowadays simply call "stars"; and the moving stars, which in Greek is called "planets".A planet certainly looks like a star (a very bright star, in some cases), but nowadays they are not usually called "stars".
Astronomers use a method called parallax to measure the distance to nearby stars. By observing how a star's position changes when viewed from different points in Earth's orbit around the Sun, astronomers can calculate the star's distance based on the angle of this apparent shift.
This is not a question. There are hundreds of stars in the Universe. Some stars even form many constellations.
It is called a constellation.Constellations.Technically an asterism, but most people usually call it a constellation.
That doesn't make sense. There are stars, and there are planets. If you mean "planets around stars, other than the Sun", those are usually called "extrasolar planets" or "exoplanets".
Clusters of stars that all appear to lie at the same distance from us are called star clusters. There are two main types: open clusters, which contain young stars and are loosely bound together, and globular clusters, which contain older stars and are tightly packed.
Constellations are not stars. Groups of stars that look like they form various objects or shapes are called constellations.
An observatory is a place specifically designed for viewing stars and planets, usually equipped with telescopes and other scientific equipment. These facilities are often located in areas with minimal light pollution to maximize visibility of celestial objects.