To understand the planets in our solar system, we have to study them in the context of their moons. This is as true of our planet Earth as it is of Jupiter. One problem Earth has to deal with that so far we haven’t had at Jupiter is the need to calibrate multiple, simultaneous missions to make sure they are all measuring things the same. NASA alone has over twenty spacecraft studying our world, and researchers are turning to the Moon for calibration.

In a NASA update on the air-LUSI telescope, Principal Investigator Kevin Turpie said: Having a common calibration source outside of the Earth will help us reach this objective. Once air-LUSI measurements are used to improve the accuracy of the total amount of light coming from the Moon, we can take extensively more accurate measurements of Earth using current and future space-borne observatories.

Air-LUSI most recently flew on March 12 to16 onboard NASA’s ER-2 aircraft, a civilian modified U2 spy plane that can fly at an altitude of 21 kilometers, which places it above 95% of the atmosphere. It measured the Moon’s brightness near full.

Turpie further explains: The Moon is extremely stable and not influenced by factors on Earth-like climate to any large degree. It becomes a very good calibration reference, an independent benchmark, by which we can set our instruments and see what’s happening with our planet.

The Moon’s brightness also isn’t affected by artificial light or other more human factors, at least not yet. For now, this nearby world will be our standard candle for measuring planet Earth.

More Information

NASA press release