'Long Distance' ETI Communication?

摘要

When I was a young boy in the early 1950s, my father, who was not a scientist, took me outdoors to view the Moon through our three-inch refractor. He asked me how long it would take a flashlight beam to "hit" the Moon. I thought that it would be instantaneous, so I said, "Real fast-zero time." My father then told me that, in fact, it would take about a second-and-a-half since light from my flashlight traveled at a limited speed. He then told me about Albert Einstein, that light could only go just so fast and that "nothing could go faster than light."