The noble gas that makes up about 0.93% of the Earth's atmosphere is argon. Argon is a colorless, odorless, and inert gas, which means it does not readily react with other substances. It is the third most abundant gas in the Earth's atmosphere after nitrogen and oxygen. Argon's primary role is in various industrial applications, such as welding and metal fabrication, where it is used to provide an inert atmosphere that prevents oxidation. Additionally, it is utilized in the production of neon signs and as a filler gas in incandescent and fluorescent light bulbs.