Nana: Hey brat, over here.
Nina: Nana, is that really you? Calling me for a voluntary chat? Or are you a changeling?
Nana: Oh, it’s me alright. Decided to give you a taste of your own karma.
Nina: Go on, Nana. This should be fun.
Nana: Do you know how rust is formed?
Nina: Sure, when oxygen combines with water molecules to interact with iron, it forms iron oxide which is colloquially called as rust. It’s basically a corrosion of the iron metal. Why are you asking? It’s strange that you would call me over to chat on rust.
Nana: Well, if you are so smart, answer this. Everyone knows there is no air on moon and consequently no oxygen. So how can there be rust on moon?
Nina: Who says the moon is rusty? You must be misinformed.
Nana: It’s the NASA that says so. And this was a key finding from Chandrayaan-2 observations.
Nina: That’s so unbelievable. Ok, I’ll bite. Explain the riddle.
Nana: The moon has no air but it is awash with hydrogen from the solar wind flows. Rust is produced when oxygen removes electrons from iron; hydrogen does the opposite by adding electrons, which means it’s all the harder for rust to form on the hydrogen-rich moon.
Nina: Why are you so contrarian today? Explain.
Nana: Earth is in a magnetic field bubble and solar wind stretches this bubble to create a long magnetic tail in the downwind direction.
The moon enters this tail three days before it’s full, and it takes six days to cross the tail and exit on the other side.
During these six days, Earth’s magnetic tail covers the moon’s surface with electrons, and all sorts of strange things can happen. Dust particles on the moon’s surface might float off the ground, and moon dust might fly into a dust storm, according to NASA.
Oxygen from the Earth travels on this magnetic tail to land on the moon, where it interacts with lunar water molecules to create rust.
Nina: Wow, Nana. You have really outdone yourself. Now, I understand why the moon is rusty.
Nana: It ain’t just the moon that is rusty. You have been rusty of late as well, walking science almanac.
This post is a part of the #NinaAndNana series I co-host with Kanika G.
PS: Here is a dystopian sci fi story on moon I wrote a while ago.