“Few people without a training in science can realize the huge isolation of the solar system. The sun with its specks of planets, its dust of planetoids, and its impalpable comets, swims in a vacant immensity that almost defeats the imagination. Beyond the orbit of Neptune there is space, vacant so far as human observation has penetrated, without warmth or light or sound, blank emptiness, for 20 million times a million. That is the smallest estimate of the distance to be traversed before the very nearest of the stars is attained.”—H.G. Wells, 1897.
It can be easy to forget that we exist in isolation, adrift in a sea of nothingness. Earth’s atmosphere provides us with the familiar, deceiving comfort of blue skies during the daytime, when in reality our planet is alone and completely enveloped in darkness. As made clear in the passage above, there really is nothing filling the void between our outer solar system and the nearest star, Proxima Centauri (PC), which is loitering at a distance of 4.24 light years from Earth. This may sound like a relatively short distance to travel is terrifyingly long. It takes light waves—traveling at the absurd cosmic speed limit of 1 billion km/hr—over four years to reach us from PC. Of course, even our fastest spacecraft do not even come close to reaching the speed of light, our fastest craft, the New Horizons probe, travels at a mere 60,000 km/hr. Assuming a straight path at this speed, it would take us just over 80,000 years to reach the nearest star (translating to somewhere around 2,700 human generations). Between us and PC exists nothing but the vacuum of space, with an average of one hydrogen atom per cubic centimeter.
Our solar system, floating in an obscure corner of an average galaxy that is 100,000 light years across, exists as a mote of dust. There is no sign of any other cosmic inhabitants other than us, and it could very well be that we exist entirely alone in this universe. I’m glad that we have each other.