“What is a Light Year and Why Do Astronomers Use It to Measure Cosmic Distances?”
A light year is a measure of astronomical distance: Light travels through a vacuum at exactly 983,571,056 feet, or 299,792,458 meters per second, making one light year 6 trillion miles, or 9.7 trillion kilometers. Image: iconacolor via Getty Images SPACE — Contrary to its name, a light year is a measure of distance, not time. … Read more