This Sunday (5), at 7:04 pm (Brasília time), the Moon reaches perigee, which is the closest point in its orbit to Earth. At the time, it will be positioned in the constellation Pisces.
According to the platform In-The-Sky.org, the Moon’s distance from Earth varies because its orbit is not perfectly circular – it is slightly oval, tracing a path called an ellipse. As it traverses this elliptical path around our planet each month, its distance varies between 356,500 km at perigee and 406,700 km at apogee (farthest point).
The angular size of the star also varies by the same factor, between 29.4 and 33.5 arc minutes. Upon reaching perigee, our natural satellite becomes up to 14% brighter in the sky, when visible. This, however, is difficult to detect in practice, as the Moon’s phases are changing at the same time.
On Monday morning (6), the Moon will reach perihelion, which is the point of its orbit closest to the Sun. This happens at 5:34 am, when it will be 1.0067 astronomical units (AU) from our host star – something around 151 million km.
As on Wednesday (8), the Moon will begin to pass between the Earth and the Sun, it is almost in the new phase, a period in which its face illuminated by the star is not facing us, which is why we can hardly observe it to the naked eye.
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About the phases of the Moon
The new moon marks the beginning of the month in lunar calendars, such as the Muslim, and in lunisolar calendars, such as the Jewish, Hindu and Buddhist.
A lunation or lunar cycle, as the time interval between new moons is called, is subtly variable, with an average duration of 29.5 days. During this period, it goes through four main phases (new, growing, full and waning), and each one lasts for approximately seven days.
There are also “interphases”: waxing and waning quarters (between the new and full phases) and waning gibbous and waning quarters (between full and waning).
