New Moon, The Invisible Phase
The Sun and Moon are aligned at the New Moon, with the Sun and Earth on opposing sides of the Moon. The New Moon is known as the "invisible phase" for two reasons: First, because of the Sun's, Moon's, and Earth's alignment, the side of the Moon that faces Earth is dark. This is referred to as a Syzygy or a conjunction. Second, the New Moon is visible in the sky during the day. It rises and sets at the same time as the Sun, putting it too near to the Sun's brightness for the human eye to perceive.
Despite this, there is one unique time when we can observe a New Moon: during a solar eclipse. In reality, the New Moon is only 'perfect' on this one occasion. Because the Moon's orbit around the Earth is somewhat inclined, the Sun, Moon, and Earth are not always precisely aligned during New Moon. It is occasionally feasible to spot a vanishingly tiny lunar crescent in the blue sky at the precise moment of New Moon with specialized equipment.
Because New Moon nights are so dark, they're great for seeing planets, meteor showers, and deep sky objects like star clusters, nebulae, and galaxies. Except during lunar eclipses, when Earth throws its shadow on the Moon, half of the Moon's surface is constantly lit by direct sunlight. Every day, the amount of light we can see from Earth fluctuates, and this is referred to as the Moon phase.
At the New Moon, the tides are higher. During the New Moon phase, the Moon and the Sun's gravitational forces combine to push the ocean's water in the same direction as they do during the Full Moon phase. Spring tides or king tides are the names given to these types of tides.
Religious and Cultural Significance of New Moon
Many religious and cultural holidays across the world are determined by the Moon. In the Chinese calendar, the New Moon in February marks the start of the Lunar Year.
The Moon becomes visible again around a day following the New Moon conjunction. The first phase, when only the tiniest sliver of a Crescent Moon is visible, was referred to as New Moon, while the darkest phase was referred to as Dark Moon. In certain societies, this old concept of the New Moon is still used to define the start of the months in the Islamic calendar.