Roughly approximately about 29.531 days, which is 4.2187 weeks.
Two weeks after the waning gibbous phase of the moon you will see a new moon.
The full lunar cycle is roughly 4 weeks, and from full-moon to new-moon is half the cycle, so it would take (roughly) 2 weeks to go from full to new moon.
A solar eclipse can only occur at the moment of New Moon. Two weeks after that moment is about 18 hours before Full Moon.
The moon has eight phases.
The Moon's phase is New Moon.
Two weeks after the waning gibbous phase of the moon you will see a new moon.
The full lunar cycle is roughly 4 weeks, and from full-moon to new-moon is half the cycle, so it would take (roughly) 2 weeks to go from full to new moon.
first quarter
The moon cycles through 4 phases every month. There are about 3 weeks between the first and last quarter phases of the moon.
Two weeks or, more precisely, about one half of the synodic period of 29.53 days.
A solar eclipse can only occur at the moment of New Moon. Two weeks after that moment is about 18 hours before Full Moon.
New Moon.
The moon has eight phases.
The Moon's phase is New Moon.
A waxing Moon can be seen when the Moon is larger in the sky, and is moving from the new Moon phase, and into the full Moon phase. A waning Moon is seen when the Moon is visibly smaller in the sky, and is moving from the full Moon phase, and into the new Moon phase.
The New Moon always occurs very close to the moon's "new moon" phase.
The moon will disappear when it is in the new moon phase, as ironic as that sounds.