In terms of time, a lightyear is, well, just one year. It’s a little more than a major league baseball season if you include spring training and post season games. One year is not much time; at least it’s not much time at my advanced age. My kids, however, might think it’s an eternity.
My contemporaries are probably better qualified to give the technical details of the distance the starship Enterprise travels in a lightyear but I can tell you this, it’s a remarkably long way.
A lightyear is the distance covered by light in one year and light travels about 186,000 miles a second, somewhat faster than Nolan Ryan’s fastball in his prime. In one year, light travels 5.86 trillion miles. It takes the suns light over 4 hours to get to the edge of our solar system, assuming Pluto is near that edge. Therefore, that light beam, if possible, could travel to Pluto and back over 1,060 times to equal the distance light travels in one year.
I tried explaining to my kids, when they were younger, the value of a million dollars. It was difficult to express, particularly when I didn’t, and still don’t, have a tangible grasp of that value myself. So it is the same when trying to describe the distance of a lightyear when I haven’t experienced that trip and probably never will.
This is how I try to wrap my feeble brain around the concept of a light year. Our moon is about 230,000 miles away. It took the Apollo astronauts about 3 days to get there at about 3,200 miles per hour, a speed just slightly more than most drivers on I-294 around Chicago. If the astronauts were to travel at the speed of light, they would arrive in just over a second saving NASA significantly on food supplies.
It is much easier to describe distance in terms of lightyears than actual miles for astronomers considering the implausible immensity of space. Our nearest star neighbor, Centauri, is about 4.4 measly lightyears from Earth or, in terms of miles, about 25,848,247,439,139 miles. That’s 25 trillion. A trillion is an unimaginable number except to our beloved politicians who like spending that kind of money. Our Apollo astronauts had to pack enough peanut butter to last over 900,000 years to get to Centauri at 3,200 miles an hour. Light, on the other hand, takes only 4 years. Centauri could flicker off today but we wouldn’t know it for 4 years.
I hope this provides a slight overview of a lightyear.