The time-viewer was a device that allowed people to view the past. Initially, the time-viewer was used by police and prosecutors, as the cost of using it was quite high. Soon after, it was put toward more lurid uses, recording sensational murders and sex-scandals for legal and bootleg sale. This source of income made it possible for the time-viewer's use for academic purposes, as historians, astronomers, and cosmologists used the time-viewer to investigate history and the universe. Recordings of these events were also recorded, again to pay for the viewer's use.
However, it was when the cosmologists tried to look before the Big Bang that the course of humanity truly changed. After three cosmologists inexplicably died looking at the period before the beginning, the French government began an investigation (the last victim, Jacques Carpentier was French). The first inspector on the case, Jean Darlan, also died, and so his friend and colleague, Jacob Dreyfus (a Jewish descendant of Alfred Dreyfus), to determine what had happened.
Dreyfus carefully went over Darlan's copious notes and viewed Darlan's death. He finally reached a possible theory, and decided to look into the past himself. After saying the Sh'mah, he looked into the past, and into the face of God. He survived, and the brief exchange he had with God proved that indeed, the Jews were God's chosen people. The world converted to Judaism in short order.
The idea of looking into the future was only briefly considered by Chaim Alexov and Moishe Hawkins. However, they quickly agreed that humanity had pushed its luck by looking into the past, and so it was better to leave well enough alone. Thus, it was a surprise three centuries later when a comet hit Earth.