Not only are there four metaphysical universes and four “prayer universes” — our prayers likewise affect the four parts of the day: daytime (say, from 6 AM to 6 PM), evening (from 6 PM to 7:30 PM), nighttime (from 7:30 PM to 4:30 AM), and daybreak (from 4:30 AM to 6 AM). The prayers we’d discussed up to now have touched upon how we transmit G- d’s Providence in the course of the daytime, so let’s now discuss prayer in the other parts of the day (as well as a prayer service that’s unique to special days).
First off, it’s important to point out that the morning service is the longest, most complex one because we need to help transmit enough of G-d’s Providence then to last the entire day. The afternoon (Mincha) service is accordingly fairly short, since only the evening has to be affected by it.
Now, since the difference between nighttime and daytime is greater than the difference between daytime and evening, and since a lot of effort has to be expended in order to transmit G-d’s Providence in the course of the night, the nighttime (Ma’ariv) service is longer than the afternoon one, and it includes the vitally important Sh’ma Yisrael and its blessings (though those blessings are much shorter than their morning version). The nighttime Sh’mone Esrei was originally not obligatory, but it has become our practice to recite it.
And though we’d expect there to be a prayer service between nighttime and daybreak, no official service was instituted in fact, since it would be too difficult for most of us to adhere to. There’s in fact a midnight service (“Tikkun Chatzot”), though, which centers on crying out to G-d to restore the Holy Temple and to end the Exile that some devout souls engage in, but it’s not at all obligatory. It was instituted by King David (while the other prayer services were instituted by Abraham, Isaac, and Jacob and thus have greater weight).
Finally, we add an additional prayer service (“Mussaf”) on Shabbat, The New Month (“Rosh Chodesh”), and on every Yom Tov, since those days merit an additional measure of Divine Providence (also see 4:6:12).