COVID-19 created chaos on Earth, but a new study has suggested that the impact of this global pandemic extended far beyond our planet.
Researchers discovered that the surface of the moon may have been indirectly impacted by global lockdown.
The team found that nighttime temperatures on the lunar surface dropped significantly during the strict COVID-19 lockdown period from April to May 2020.
They believe this strange phenomenon can be explained by a significant decrease in greenhouse gas emissions during lockdown, which ultimately led to cooling of the lunar surface.
Nighttime temperatures on the lunar surface significantly dropped at six different sites during the strict COVID-19 lockdown period from April to May 2020, new research suggests
‘The Moon has possibly experienced the effect of COVID-19 lockdown, visualized as an anomalous decrease in lunar nighttime surface temperatures during that period,’ the researchers stated in their report.
A pair of researchers from the Physical Research Laboratory in Ahmedabad, India, analyzed lunar nighttime surface temperatures at six different sites on the moon’s nearside – or the side that always faces Earth.
These temperature records were created by NASA’s Lunar Reconnaissance Orbiter (LRO) which launched in 2009.
The LRO is equipped with an instrument that uses seven thermal infrared cameras to take the temperature of the lunar surface.
The team looked at temperatures recorded from 2017 to 2023, uncovering something strange in the data taken between April and May 2020.
Across all six sites, the researchers found an anomalous dip in temperatures ranging from eight to ten degrees kelvin (or roughly 14 to 18 degrees Fahrenheit) that appeared to correspond to this period of lockdown.
The lowest of all the temperatures was recorded one of two sites in Oceanus Procellarum – a large, dark plain on the moon’s nearside.
There, temperatures dropped as low as 96.2 K, or -286 F. For comparison, temperatures at this site went as high as 131.7 K, or -222 F, in 2022.
The average temperature of the moon at its equator and mid-latitudes ranges from -298 F during lunar nighttime to 224 F during lunar daytime.
The researchers analyzed lunar surface temperature data taken by NASA’s Lunar Reconnaissance Orbiter.
The researchers hypothesize that this cooldown was caused by a sudden drop in radiation being emitted from Earth as human activity ground to a halt during lockdown, which in turn reduced the amount of heat escaping the atmosphere.
They published their findings this month in the journal Monthly Notices of the Royal Astronomical Society: Letters.
The first wave of COVID-19 swept across the world in March 2020. At this time, vaccines were not yet available.
So, governments around the globe issued strict lockdown protocols in an attempt to slow the spread of the virus. By April, roughly half of the global population had been asked or ordered to stay inside.
This significantly reduced the amount of terrestrial radiation being generated on Earth. That’s because lockdown interrupted many greenhouse-gas-generating activities such as commuting, industrialization and mining.
Lockdown reduced global daily greenhouse gas emissions, which in turn reduced the amount of heat radiating off of Earth
A reduction in Earth’s radiated heat could explain why the lunar surface cooled down in the spring of 2020, the researchers argue
In fact, research has shown that daily global CO2 emissions dropped roughly 17 percent by early April 2020 compared to average 2019 levels.
When sunlight reaches the Earth, some of that radiation is absorbed by our planet’s surface and atmosphere. This causes the Earth to heat up, thus generating terrestrial infrared radiation – or radiated heat.
When there are high concentrations of greenhouse gases such as CO2, water vapor and methane, these gases absorb Earth’s terrestrial heat and then re-emit it back into space.
But during lockdown, a global reduction in emissions led to a decrease in cloud cover and atmospheric pollutants over many nations. Therefore, the amount of heat emitted by Earth also decreased, the researchers explained in their report.
The temperature dip that the researchers detected across the moon’s near side – or the side that always faces Earth – suggests that some of our planet’s emitted heat impacts and warms the lunar surface.
This would explain why the temperature of the lunar surface decreased during a period of decreased greenhouse gas emissions.
More research is needed to establish conclusive links between the two phenomenon, the researchers stated in their report. But this study points to lunar surface temperatures as a new way to study the effects of climate change on Earth.