The speed of light in vacuum, commonly denoted \(c\), is a universal physical constant that is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour).
Bibliography
“Speed of Light.” 2023. Wikipedia, March. https://en.wikipedia.org/w/index.php?title=Speed_of_light&oldid=1144915324.