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 Before the Copyright Act of 1976 became effective on 1 Jan 1978, unpublished works were.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.
The Copyright Act uses the phrase works of authorship to describe the types of works that are protected by copyright law. This purposefully broad phrase was chosen by Congress to avoid the need to rewrite the Copyright Act every time a new medium was discovered.