What Do Stars Look Like?
When people think of stars, what images come to mind? I’ve seen many different movies and TV shows where the characters look at the stars in the skies above, and sometimes even try to touch them with their hands! There is a real fascination with these heavenly bodies that are often taken for granted by the human species. A star is usually an ordinary, luminous celestial object made up of a rotating, hot plasma held together by its mutual gravity. The very closest star to Earth is known as the Sun, at only 4.6 light-years away.
Stars can be classified according to the elements that make up their surface and composition. One of the most common types is a gas star, made mostly of hydrogen (with helium making up the main component in a few stars), with many times more iron than hydrogen. A main reason that stars have a “gas” like appearance is because their surface is filled with very hot and dense gaseous matter, which in turn is electrically charged. The other main class of stars is a rocky star, with extremely high composition of iron (especially rich in lithium), aluminum, and a small percentage of other elements. Although stars can also be made of matter that does not have a “gaseous” composition, this is rare in nature.
Stars can be grouped into two main sequences: main sequence stars (with only one star in the main sequence) and secondary sequence stars (which contain two or more stars in the main sequence). In a main sequence star, all of the elements that make up the star are in their most stable state, i.e. together. In a secondary sequence, elements that are relatively unstable begin to combine and sometimes become much more volatile. Whether you call a star a “star” depends on your personal preference.