How did the moon get to be like it is, and why is it so different Earth in terms of the fields that it has? Join us as we discuss how the Moon's magnetic field disappeared a BILLION years and a study just Discovered Why!
If you were to try and list all the things that are important to the Earth that are outside the Earth itself, the top two things you'd likely list are the sun and the moon. Both the sun and the moon play a BIG part of what's going on in our world, from the heat that we get, to the light that we see both in the day and in the nighttime, and their gravities both keep us in a stable orbit and affect things like our oceans in a fair way. But, as we continue to look at the moon and the sun, we continue to wonder how they came to be, and what changes they had over the years.
Now, a recent study has shown that not unlike the Earth, the moon once had a very strong magnetic field once upon a time. But around a billion years ago, it basically disappeared.
How is it possible that we know this? Moon rocks. Some of the rocks that we had gotten from the moon were formed via impacts, probably from meteors or even asteroids (albeit small ones) and when these impacts formed new rocks, they gave a "snapshot" of the magnetic field to the rocks themselves via the grains inside them. It's complicated, but it's science.
Anyway, by examining these rocks, it was found out that about a billion years ago, the magnetic field of the moon dropped from a very strong entity to only 0.1 microteslas — around 500 times weaker than the Earth's today. Which is a significant drop no matter which way you choose to look at it.
But how is it possible that the magnetic field of the moon had dropped like that a billion years ago? That would be the dynamo that was powering the field itself. Or in other words, the liquid core of the moon. A liquid core is needed to make a electromagnetic field, and while the moon did have one at one time, by the point of a million years ago, it had cooled and crystallized, or so we speculate, and due to that, the field diminished in power by a large margin.
'A strong field on the moon may have shielded the surface from the solar wind, the supersonic plasma emitted from the sun,' planetary scientist Benjamin Weiss of the Massachusetts Institute of Technology told Newsweek.
He went on to note:
'This may have prevented the surface from being space weathered and the soil becoming rich in solar gases, like it is today.'
So basically, how the moon looks right now may be directly tied to the loss of its magnetic field, which if that sounds familiar, that would be because it's the same thing that happened to Mars. The red planet once had a powerful atmosphere and magnetic field, but eventually that changed, and now Mars does not have an intrinsic global magnetic field. However, it does have a magnetosphere due to interactions with solar winds.
But that's not enough to keep a lot of the solar radiation from bombarding the planet, and thus making the atmosphere even more unstable. As a result, Mars looks like it does right now, and that might have been what happened to the moon once its core cooled down.
Scientists also point out that when the magnetic field of the moon was up, it might have been closer to the Earth.
'Furthermore, the Moon was likely about twice as close to the Earth during the time the Moon was inferred to have a strong magnetic field compared [with] today.'
This would be a very interesting twist on the history of our planet, because as you hopefully know, the moon drastically affects things on Earth, including the gravity it exerts on the planets oceans. So, if it was "twice as close" as it is now about a billion years ago, that would mean that the Earth has gone through some serious tidal shifts because of the placement of the moon.
Not to mention, this would further show how the moon is drifting away from the planet. The gravity of the two massive objects do seem to imply that they are in a "locked formation" with one another, but that's actually not true. The forces are slowly pushing them apart, and so every year, the moon gets 1 inch away from Earth. Granted, that's not a lot of movement for a lot of time, as it would be over a decade before it would be another foot away, but eventually, that will affect the Earth in a significant manner.
Video Chapters:
00:00 Introduction
00:21 The Moon Once Had A Very Strong Magnetic Field
01:42 The Role of Dynamo Theory in Moon's Magnetic Field
06:10 The Magnetic field
08:20 Giant Impact Theory
10:00 Why Is It Important To Dissect?
#insanecuriosity #moon #magneticfield
