Science
The development of spaceflight within the second half of the century allowed the primary astronomical measurements carried out on or close to other objects in space, including six manned landings on the Moon. Space telescopes lead to numerous discoveries in astronomy and cosmology. Evolution turned a unified theory within the early 20th-century when the trendy synthesis reconciled Darwinian evolution with classical genetics. The molecular structure of DNA was discovered by James Watson and Francis Crick in 1953. Albert Einstein's theory of relativity and the development of quantum mechanics led to the replacement of classical mechanics with a new physics which incorporates two elements that describe several types of occasions in nature. Early in the 19th century, John Dalton advised the modern atomic theory, based mostly on Democritus's authentic thought of indivisible particles called atoms. Mental sicknesses are the leading explanation for disability in the US and Canada...