A University of Wisconsin researcher believes that the Moon might be the best place from which to study climatic changes taking place on Earth.
According to Shoapeng Huang, National Aeronautic Space Agency (NASA) data collected over a period of 41 months in the 1970s show variations taking place in the Moon's surface temperature.
Accessing this NASA data collected through instruments left on the Moon's surface between 1971 and 1975 by the Apollo 15 mission, Huang reveals in an article published in the Advances in Space Research, that the daytime temperatures, affected by radiation coming from the sun, are not so interesting, but concludes that night temperatures on the Moon are driven by radiation from the Earth.
Opining that the Earth's radiation should decrease as rising levels of greenhouse gasses in the atmosphere retain more and more of the sun's energy, Huang says that 'if the Earth reflects less energy back into space, then the Moon should feel it.'
NASA records show a slight increase in night-time temperatures between 1972 and 1975, says Huang. He thinks this could be a consequence of 'global dimming', the phenomenon which led to cooler temperatures on Earth at the time. The dimming is thought to have been caused by an increase in reflective particles in the atmosphere.
Based on these results, Huang would like to see further investment in getting instruments to the Moon to monitor the Earth's radiation from there. He believes the Moon is the Earth's only stable natural satellite and does not have an atmosphere, biosphere or any water, all of which would interfere with radiation from Earth.
Meanwhile, NASA is already attempting to monitor earthshine using a man-made satellite instrument called CERES.
Bruce Wielicki of NASA, who runs the CERES experiments, does not agree with Huang's findings, and says that the Moon is actually a very poor place to monitor the Earth's changing radiation signals.
Using computer models to simulate Moon-based observations of earthshine, Wielicki found that the Moon's tilted orbit relative to Earth prevents the instruments on its surface from getting good measurements from the poles.
What is more, a day on the Moon lasts 28 Earth days. The mismatch makes it difficult to interpret variations in radiation, which can be caused by seasons on Earth, Wielicki says, and also observes that placing instruments on the Moon is much more expensive than launching them into low Earth orbit.