Dark Matter – Meaning and Importance

Dark matter was predicted in the past, but wherever scientists trained their telescopes and instruments in the heavens, they found only the hundred or so familiar chemical elements existing on the earth. Even stars in the farthest reaches of the universe are made of ordinary hydrogen, helium, oxygen, carbon, et cetera. On one hand, this was reassuring; we knew that wherever we traveled in outer space, our rocket ships would encounter only the chemical elements found on the earth. On the other hand, it was a bit disappointing knowing that there would be no surprises in outer space.

Submarine Definition & Meaning

The submarine has been one of the most important inventions man has ever seen. A submarine is a vessel that can travel on the surface of the water as well as underwater. It is shaped like a cigar, and can be tightly closed from all sides. There are different types of submarines, which can travel underwater at different depths. They are usually powered by disesel-elelectric engines, but some are nuclear-powered also

Failure of Quantum Mechanics without Relativity

Philosophical questions aside, in the 1930s and 1940s quantum mechanics was like an unstoppable Mack truck barreling down a highway, flattening all the problems that had puzzled physicists for centuries. One brash young quantum physicist, Paul Dirac, ruffled the feathers of many chemists when he had the nerve to say that quantum mechanics could reduce all of chemistry to a set of mathematical equations.