The coronavirus pandemic has lowered the temperature on the Moon.

Astronomers have shared intriguing data from the Lunar Reconnaissance Orbiter (LRO). This spacecraft orbits the Moon at altitudes ranging from 20 to 165 kilometers and is equipped with a radiometer—a device used to measure radiation power. It helps to determine the temperature of the lunar surface.

An analysis of its data over the past few years revealed abnormal nighttime cooling on the Moon in April and May of 2020: in the areas not illuminated by the Sun during this time, temperatures dropped by several degrees, and on some days, by nearly 10 degrees. Notably, this phenomenon was observed specifically on the side of the Moon that faces Earth.

When night falls on the near side of the Moon, it does not completely succumb to darkness. By closely observing the lunar month, one can notice that the dark part of the surface is still discernible. This phenomenon is referred to as "ash light." It occurs because sunlight is reflected off the Earth and falls on the Moon. It turns out that the planet not only "illuminates" it but also slightly warms it.

Astronomers examined temperatures in six different locations: two points in the Ocean of Storms, and one each in the Sea of Serenity, Sea of Rains, Sea of Tranquility, and Sea of Crises. All selected regions are located in the equatorial and mid-latitudes of the Moon, where the most sunlight reaches. It was discovered that during the spring of 2020, a similar trend was observed during lunar nights everywhere: it was noticeably colder.

This was reported by scientists from the Indian Laboratory for Physical Research. In their article, published in Monthly Notices of the Royal Astronomical Society, they provided an unexpected explanation for this unusual phenomenon: it is a consequence of the coronavirus lockdown.

The researchers emphasized that the heating of the Earth's atmosphere by the Sun causes it to emit infrared radiation. The "amount" of this radiation depends on the concentration of greenhouse gases in our air. The more greenhouse gases present, the more infrared light is emitted from the planet, noted the physicists.

The spring of 2020 was marked by the strictest restrictions due to the Covid-19 pandemic: industrial production decreased, traffic jams vanished due to the self-isolation regime, and all of this temporarily reduced anthropogenic emissions. Consequently, less infrared radiation was emitted from the atmosphere and reached the Moon. The scientists concluded that this was what reduced the surface heating.