So far, at least three separate previously unknown or simply unconfirmed things were discovered about our immediate observable Universe this year. The most recent one involves the moon, and even though not very relevant, it is still an important thing to know. According to a study from the University of Washington, the moon directly affects rainfalls on Earth.
It all started as an accidental observation
As University of Washington doctoral student Tsubasa Kohyama was studying atmospheric waves one day, he accidentally observed a slight oscillation in the air pressure.
This determined the doctoral student, along with his sub-supervising professor Dr. John M. Wallace, to start investigating the phenomenon.
They would eventually reach the conclusion that the phases of the moon influence rainfall levels on Earth, albeit just by 1% compared to the total rainfall variation.
The scientific process behind the study
For two years, the two authors looked at data related to air pressure and the position of the moon.
They looked at 15 years’ worth of data obtained from both NASA and the Japan Aerospace Exploration Agency (JAEA’s Tropical Rainfall Measuring Mission used a satellite for this from 1998 to 2012), making sure to collect as much needed information as possible.
They also had access to data from 1932 and even 1847, tying air pressure and temperature changes to phases of the moon.
By using whatever resources they had, including a previous University of Washington paper confirming that air pressure varies depending on the moon’s phases, the team managed to finish their paper after a few years, finally getting the answer they were looking for.
M-O-O-N – that spells moon
As it turns out, the reason why the moon affects the earthly rainfall is because of its gravity’s effect on the Earth’s atmosphere.
When the moon is either overhead or underfoot, the air pressure in that point is slightly higher, as the moon’s gravity causes the atmosphere to bulge toward it for a little.
This causes the air pressure in that area to also slightly elevate, heating up the air in the region.
You’ve probably noticed in the searing heats of this summer, if you didn’t know already, that warm air can hold more moisture (this is why dry heat feels better).
Therefore, the increased humidity causes more precipitations in that area.
Now, the study authors warn that the change is of only about 1% compared to regular rainfalls, so it is virtually insignificant; however it is useful to know in future air pressure studies.
Image source: Pixabay