A billion years is commonly called an eon, especially in the contexts of geology and astronomy.
While "billion years" is perfectly acceptable, "eon" offers a more concise and technically relevant term when discussing vast stretches of time, particularly in scientific fields that deal with the Earth's or the universe's history. An eon is the largest division of geologic time.
Here's a breakdown to further clarify:
- Billion Years: This is the literal and most straightforward way to express the quantity of time.
- Eon: This is the formal term used in geology and astronomy to refer to a period of one billion years or more.
Therefore, both terms are correct, but "eon" carries a specific scientific connotation.
