Answer: The hierarchical formation model suggests that galaxies may have been formed by subsequent mergers of smaller galaxies and that today each galaxy houses at least a supermassive black hole.
Explanation: During a fusion of galaxies, the stars that composes it suffer the tidal force, intensifying your action as the galaxies approaching. When two galaxies merges themselves, the astronomers believes that they loss a huge part of their mass, forming the supremassive black hole, that stays in the middle of the galaxie.
The supermassive black holes are originated from the evolution of high mass stars. They were formed by huge clouds of gas or clusters of millions of stars that collapsed on their own gravity when the universe was still much younger and denser.
The first human made object made to orbit earth was the Soviet Union's Sputnik 1, it launched the 4th of October 1957.
Explanation:
The average speed of a modern cruise ship is roughly 20 knots (23 miles per hour), with maximum speeds reaching about 30 knots (34.5 miles per hour).