In the early decades on the 20<sup>th</sup> century, two new theories of "modern physics", [[Relativity]] and [[Quantum Mechanics]], had come into existence. Both were known for being very abstruse. He popularized them, both for experts and for the general public. He particularly worked on getting relativity better known, both by the scientific community and by the public. [[General Relativity]] was something he worked especially hard at. | In the early decades on the 20<sup>th</sup> century, two new theories of "modern physics", [[Relativity]] and [[Quantum Mechanics]], had come into existence. Both were known for being very abstruse. He popularized them, both for experts and for the general public. He particularly worked on getting relativity better known, both by the scientific community and by the public. [[General Relativity]] was something he worked especially hard at. |