Imagine that you live alone in a dark, hilly wood that stretches for miles in all directions. You know your own forest well, having hiked and surveyed it as far as your feet and your tools allow. In all these explorations, you have never met another soul. For all you know, you're the only person there is.
Then one day, at the top of the highest point in your forest, you see a light in the distance. It's too far away to tell who or what is generating it. You have no idea if it's meant to catch your attention, or if you're merely observing the activity of something that has no idea that you are there.
But the light confirms a suspicion you've harbored for some time: You are not alone.
If there is intelligent life beyond this planet, this is the way astronomers and planetary scientists believe we will first notice it.
To read more, click here.