Observing Basics: Distances in Space

Light's constant speed helps astronomers and observers better understand the vastness of our universe.
By | Published: January 9, 2013 | Last updated on May 18, 2023
Light travels at a constant speed of 299,702,458 meters per second (186,282 miles per second). That’s equal to more than 670 million mph (1.08 billion km/hr). So the distance light travels in a year is known as the light-year, and it’s equivalent to 5.88 trillion miles (9.46 trillion km).

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