I believe it's quadratic, as quadratic matches the second time while linear matches the first time you find the differences.
World War 1 because as Taskmasters said on this website, "Dadaism was an art movement of the European avant-garde, in the early 20th century, which was heavily influenced by World War I. It was anti-war and anti-bourgeois, and had political affinities with radical left. Some of the key figures of the Dada movement were: Hugo Ball, Emmy Hennings, Hans Arp, George Grosz, Max Ernst, Beatrice Wood, Tristan Tzara, Francis Picabia, etc. The movement influenced later styles in art such as Surrealism, Nouveau Realisme, pop art and Fluxus." (I quoted another guy's answer a.k.a. Taskmasters.
Around a distant star, two planets similar to Earth collided and were destroyed, astronomers said today.
The somewhat speculative scenario is based on the leftovers: a ring of debris around the star that includes a million times more dust than now circles our sun.
