The beginning of the 20th century brought the start of a revolution in physics. The long-held theories of Newton were shown not to be correct in all circumstances. Beginning in 1900, Max Planck, Albert Einstein, Niels Bohr and others developed quantum theories to explain various anomalous experimental results, by introducing discrete energy levels. Not only did quantum mechanics show that the laws of motion did not hold on small scales, but even more disturbingly, the theory of general relativity, proposed by Einstein in 1915, showed that the fixed background of spacetime, on which both Newtonian mechanics and special relativity depended, could not exist. In 1925, Werner Heisenberg and Erwin Schrödinger formulated quantum mechanics, which explained the preceding quantum theories. The observation by Edwin Hubble in 1929 that the speed at which galaxies recede positively correlates with their distance, led to the understanding that the universe is expanding, and the formulation of the Big Bang theory by Georges Lemaître. COUNT 5
QSN1 What science subject explains anomalous results? ANS1 quantum theories QSN2 What year did Einstein discover the theory of general relativity? ANS2 1915 QSN3 Quantum theories became which subject in 1925? ANS3 quantum mechanics QSN4 Which scientist noticed the relationship between the speed and distance of galaxies? ANS4 Edwin Hubble QSN5 Edwin Hubble's discovery about galaxies allowed for which theory by Georges Lemaitre? ANS5 the Big Bang theory