WE HAVE BARELY LEFT EARTH — AND THE NUMBERS ARE SHOCKING Humanity has sent people to the Moon, built machines that can see billions of light-years away, and created spacecraft that have been traveling through space for decades. The observable universe is about 93 billion light-years across. It contains an almost unimaginable number of galaxies, stars, planets, and worlds that we may never be able to reach. Yet the farthest any human being has ever traveled from Earth is only about 1.3 light-seconds. That record was set during the Apollo missions, when astronauts traveled to the Moon. Light can cross the greatest distance humans have ever traveled in roughly 1.3 seconds. But crossing the diameter of the observable universe would take light about 93 billion years. Voyager 1, one of humanity's most distant spacecraft, has been traveling away from Earth for nearly five decades. Yet even after all that time, it has covered only around 22 light-hours. The universe is so enormous that our greatest journeys barely register on its scale. We have reached the Moon. We have sent robots beyond the planets. We can detect galaxies from the early universe. But in terms of the cosmic ocean around us, humanity is still standing on the shoreline. Source: NASA Glenn Research Center, “Seeing the Earth, Moon, and Sun to Scale” (2023)