Earth's magnetic field has anomaly!

 As the seniors were discussing, the earth's magnetic field is constantly changing, and every 200,000 or so years, on average, it reverses! Compasses will point south someday, as they have many times in earth's history. 

From computer simulations, one thing that happens before a reversal is the earth's overall magnetic field weakens, and then anomalies in the field begin to form - small regions of the field where it begins to reverse itself, due to complex fluid dynamics going on in the earth's liquid iron outer-core. Scientists are identifying such anomalies, suggesting that the weakening field (the has in fact decreased at a quick pace over the last few centuries) may be getting set for a full reversal! This is something to follow in the coming years, to see how the field evolves.