The moon is getting dusted off, and some of its contents – like lunar rocks – are becoming the center of a new debate. The newly ignited debate stems around what was a magnetic field around the moon and the strength of that very field. Scientists have long speculated and hypothesized that the moon had a magnetic field of its own at one time that was generated in part by the electrically conductive fluids that rest at the core of the moon.
It’s been dubbed as “the moon’s magnetic heart,” and the reach of the magnetic heart was definitely impressive. Researchers are now convinced that the magnetic field that was present on the moon – as is evident by the lunar objects that have been returned to Earth from early Apollo missions suggest that the magnetic field was stronger than the one present on Earth today.
According to those scientists that magnetic field was likely present billions of years ago, being long gone today, but its existence was something that they were previously uncertain about. Even more curious was the question surrounding the reason the magnetic field existed. Some scientists believed that an outside force was at play – which scientifically was possible – while the others believed internal workings of the moon were what created the magnetic field.
Scientists pointed out that “The moon is intermediate between a planet and a small body like an asteroid, so establishing whether the moon had an ancient dynamo could help show that it was a highly evolved body differentiated into layers like Earth,” even going as far as to say, “This would tell you about the origin of the moon – some models say the moon started off cold and unmelted, while other suggest it was created from a giant impact and predict should have been hot.”
Overall, a lot of uncertainty around the moon has existed for decades, even before the Apollo missions and the decade-long race to get to the moon in the 60s. Earth has a magnetic field strength today of 50 microteslas, according to Benjamin Weiss, a planetary scientist at MIT – and the co-author of this study. For roughly a billion years after, the moon was formed it had a magnetic field strength of 70 microteslas.
However, if the core is what generated the magnetic field – which scientists are currently leaning toward – it would have done so miraculously since the moon has a very small core in comparison to Earth. The size of the core is what ultimately dictates the strength of the magnetic field. Now scientists must grapple with understanding why it died, and why it died slowly over time.