Radon is a dangerous gas. It is colorless and odorless and is always being emitted from our planet-don't worry, it's not enough to harm you.
Copyright for published works in the USA has been according to a federal copyright statute, since the first U.S. copyright statute in the year 1790. Before the Copyright Act of 1976 became effective on 1 Jan 1978, unpublished works were. protected by state law, known as common-law copyright.
See Circular 1, Copyright Basics, section What Works Are Protected. How is a copyright different from a patent or a trademark? Copyright protects original works of authorship, while a patent protects inventions or discoveries. Ideas and discoveries are not protected by the copyright law, although the way in which they are expressed may be.