The Oort cloud is a huge spherical cloud of comets and dust that extends three light years from the Sun in all directions. The fact that the cloud is spherical rather than disc-shaped sets it apart from other collections of debris in the solar system, such as the asteroid and Kuiper belts. The sphere is so large that its edge is closer to our nearest star than to the sun itself. The edges of the Oort cloud generally represent the limits of the sun’s gravitational influence — comets that stray too far from the edge get lost into space and become interstellar wanderers.
The Oort cloud was first theorized in 1950 when Jan Oort observed that there were no comets with orbits that indicate they come from outside the solar system, that there is a strong tendency for comet orbits to take them out as far as 50,000 AU (50,000 times the distance between the earth and the sun), and that these comets arrive and depart randomly in all directions.
This led to the hypothesis of the Oort cloud, a cloud that cannot be directly observed with telescopes because the comets that make it up are too small and far apart. It is estimated there are about a trillion comets in the Oort cloud, with a combined mass 100 times that of the Earth. It is theorized that Oort cloud objects actually formed relatively close to the sun, closer than Neptune’s orbit, but were ejected into huge parabolic orbits when they were slungshot by the gravity wells of huge planets like Jupiter.
(Source: Wise Geek)
Picture yourself as the sun. Around you are the planets. These are your fellow wanderers through the cosmos. Their orbits may be brazenly intimate or freezingly estranged but you are entwined, nonetheless.
Farther out, beyond your most distant, least agreeable companions is the Oort Cloud of people you do not actually know. You may be at the same school, in the same workplace, walk the same pavements, at the same bus stops. But you don’t know them. If you do see them, there’s the vague recognition of having seen a face before which stops way short of ‘oh, them again!’
Then something happens to perturb that situation. The human equivalent of a passing star or molecular hydrogen cloud: maybe a random comment on a Facebook picture or a chance mention in a fanzine. But something happens.
The person who was light-years away now falls toward you. A smile becomes a ‘hello,’ a wave becomes a drunken hug on a dancefloor. You know who they are, they know who you are.
Maybe a stable orbit will form. They won’t be a planet but they could be comets, passing by every now and then. Hell, that might be more fun than some of the planets who cruise round you, grumbling and groaning. Yeah, maybe that happens. After all, who doesn’t need more comets?
Or maybe this will happen…
They fall into you. You fall into them. The heat and intensity is unbearable. You feel that you’ll both evaporate away, immolated by the fierceness, the sweetness of your trajectories. They’re closer than any planet, they’re more important than anything or anybody.
And then, they’re gone. The sharp angle of the approach made them slingshot away from you. The speed of the fall, the directness of their line into you is what now propels them away from you. If there had been less attraction, they might have stayed in a stable orbit or maybe even ended up back in the cloud of unknowns.
But you were too intimate for that. As they recede, red-shifting with the pain of the affair, you know you’ll never know them again. Texts won’t be returned, letters won’t be read, no further information can possibly bridge the sparkling, quotidian coldness between you both.
They go beyond the Oort Cloud. They’re tens of light-years away now, heading towards other attractors.
And you’re on your own again.