On April 6, 1802, Norwegian mathematician Niels Henrik Abel passed away. Abel is well known in mathematics for proving the impossibility of solving the quintic equation by radicals. In parallel to Évariste Galois - who also died young - , he laid the foundations of group theory.
On October 7, 1885, Danish physicist and Nobel Laureate Niels Bohr was born. Bohr made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922.