While not an invention in the literal sense – it was not a creation per se – Einstein’s Special Theory of Relativity was, and is, one of the most ground breaking science breakthroughs of all time. This was made in 1905, and built on the three century old Galileo principle of relativity. Some of the central assertions to this theory are that time and space are relative to the observer, the speed of light is the maximum attainable velocity in the universe, and that mass and energy are interchangeable according to the equation E=mc^2.
While Einstein cannot be credited with the invention of the atomic bomb, the famous equation above is the theoretical basis of it. Energy (E) = mass (m) x the speed of light in a vacuum (c^2). The most famous consequence of this was its application in the atomic bomb – By measuring the mass of different atomic nuclei and subtracting from that number the total mass of the protons and neutrons as they would weigh separately, one could obtain an estimate of the binding energy available within an atomic nucleus. This could be (and was) used in estimating the energy released in the nuclear reaction, by comparing the binding energy of the nuclei that enter and exit the reaction.
Einstein also gave the solution to the question, “Why is the sky blue”, in 1911, through a formula that explained how light scattered off of air molecules.
In 1916, Einstein expanded his Special Theory of Relativity to include a General Theory of Relativity. This theory is primarily concerned with large scale effects of gravitation. This has been one of the cornerstones of cosmology and our understanding and view of the universe – primarily that large celestial bodies produce curvatures in space-time, which forms a gravitational field. From a planets gravitational pull of its moons to black holes, the General Theory of Relativity is incredibly broad.
The Bose-Einstein Condensate is a state of matter formed by bosons cooled to temperatures very near to absolute zero. It was proposed by Einstein in 1925 and built upon the work of Satyendra Nath Bose, hence the name.
Einstein was an incredible individual who changed the way we see and explain our universe – even over 50 years after his death, this theories are still in use and referenced.