10 Things We Didn’t Know 100 Years Ago

Almost half a million of the people alive today were alive 100 years ago. These same people have seen so much during that time and we’ve learned far more than the great lights of that day could have ever imagined. Ironically, it was through some of those great lights that we have progressed as far as we have and, as Newton said so eloquently, “If I have seen further, it is by standing on ye shoulders of giants“.

1. James Chadwick discovers the Neutron. We didn’t know that there is a particle similar to the proton with the same mass but without an electric charge. Through various experiments involving helium nuclei, James Chadwick discovered the Neutron in 1932. Only within this year (March 2016) has the Standard Model of Particle Physics been completed with the confirmed discovery of the Higgs Boson, thereby completing the model that Chadwick and so many other brilliant lights contributed to.
2. DNA Discovered to be in the Shape of a Double Helix through the use of X-ray diffraction.
3. Vitamin C was discovered.
4. Antibiotics (Penicillin) were discovered and developed by Alexander Fleming in 1928 for which he shared the Nobel Prize in Physiology or Medicine in 1945 with Howard Florey and Ernst Boris Chain. Thus began the eradication of many deadly and heretofore untouchable infectious diseases.
5. The Universe was discovered to extend far beyond the Milky Way Galaxy. Known as the “Great Debate”, the issue was debated by Harlow Shapley and Heber Curtis and centered around the nature of the so-called spiral nebulae (we know them today to be spiral galaxies) and the size of the universe. Using the Period-Luminosity relation developed by Henrietta Swan-Leavitt and her studies of Cepheid Variable stars, Edwin Hubble unequivocally answers the question by observing these stars in the Great Spiral Galaxy in Andromeda with the 2.5 meter (100 inch) Mt. Wilson telescope.
6. Hydrogen was discovered to be the most abundant element in the universe. Cecilia Payne-Gaposchkin successfully defended her 1925 Ph.D thesis “Stellar Atmospheres, A Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars” wherein she established that hydrogen was the overwhelming constituent of the stars by a factor of one million and thus, the most abundant element in the Universe.
7. Tectonic Plates were discovered in 1915 by Alfred Wegener
8. Evolution of Modern Humans. Louis Leaky and his family begin their work in East Africa during the first half of the twentieth century, providing strong evidence for the proposition that the progenitor of the modern human race is traceable back to a common African ancestor.
9. CFCs (Chlorofluorocarbons) were observed to deplete and destroy Ozone
10. Einstein’s General Theory of Relativity has stood the long test of time over the intervening 101 years since he published the theory in November of 1915. The most recent and, arguably, the most visible test is the confirmed observation of gravity waves, postulated as an aspect of General Relativity.