The asteroid belt is nothing but tourist traps, and the rest stops really thin out after Saturn. Some of you will want to consider flying. Luckily, at a Boeing 777's maximum velocity of 590 miles per hour, the trip to Pluto will take only about 680 years.
Yet structures like the Pantheon and the Colosseum have survived for centuries, often with little to no maintenance. Geologists, archaeologists and engineers are studying the properties of ancient Roman concrete to solve the mystery of its longevity. âRoman concrete is . . . considerably weaker than modern concretes. Itâs approximately ten times weaker,â says Renato Perucchio, a mechanical engineer at the University of Rochester in New York.
concretenoun [ U ] uk â /ËkÉÅ.kriËt/ us â /ËkÉËn.kriËt/. B2 a very hard building material made by mixing together cement, sand, small stones, and water: reinforced concrete. a concrete floor/path. a grey concrete building. More examples. The bomb shelter has concrete walls that are three metres thick. The foundation of the house is built from rubble overlaid with concrete.