The Reckoning

The Reckoning is an event in Sburb within Homestuck. As part of the continuing battle between dark and light, the Reckoning apparently occurs when the dark royalty uses the meteors from The Veil in an attempt to destroy Skaia. As part of a defense Skaia uses portals to transport the meteors elsewhere, specifically to Earth. Due to the timelessness of The Medium the meteors fall throughout time. These seemingly create many paradoxes by causing the children to become more embroiled in Sburb.

According to CarcinoGeneticist, the Homestuck Kids' session of Sburb will have the Reckoning occur much earlier, apparently on account of Jack Noir.

Paradox Clones
The Reckoning is an important part of the story of the Paradox Clones. According to CarcinoGeneticist this is how the babies are transported back in time, and across the earth to their respective guardians. CarcinoGeneticist states that they were sent through the defense gates.

Speculation
It is extremely possible that the various technologies that grew from the meteor craters are connected to the original labs and factories on the Veil meteors. This includes the Frog Temple as well as the bases seen at each childs House.