eli5-what is a lunar standstil
In: Planetary Science
It is simply when the Moon reaches its furthest point north or south in the sky. Kind of like a solstice, but with the Moon.
There is an upcoming major lunar standstill in 2025 and they happen every 18.6 years.
There are also minor standstill, which happens half way through the 18.6 year cycle. The last being in 2015 and the next being in 2034.
The major lunar standstill the Moon reaches a declination of 28.72° (North or South) that means it will be directly above your head at a lattitude of 28.72° (north or south depending on which one the Moon is at)
During a minor lunar standstill, it only reaches a declination of 18.13° (again, north or south)
If you were to watch this entire lunar cycle as a big 18.6 year time-lapse, the Moon would drift up and down throughout the process, but the standstill is a maximum that it reaches.
The Earth is tilted about 23.4°, and the Moon’s orbit is tilted about 5.3° relative to the Earth’s orbit, so when they add together, you get 28.7° and when they subtract, you get 18.1°. The Earth and Moon just sync up perfectly to get these maxima every 18.6 years.
18.6 years is also the length of the cycles on which lunar and solar eclipses occur during
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