In case you didn’t know, the universe is a terribly hostile place for most lifeforms. Take our own star, for example. The sun gives life to everything on Earth, but it is also a violent inferno (one that is capable of destroying all living things). Fortunately, for us, our planet has protection—it is surrounded by a magnetic force field. Okay, perhaps “force field” is a bit sensationalist, but the actual description is just as inspiring. The Earth is encased in a magnetic field, which is generated by the rotating, liquid iron core at the center of the planet (otherwise known as a “dynamo”).
And it seems that this magnetic field changes rather rapidly.
A magnetic field shift in our planet is nothing new. The poles have flipped several times throughout Earth's history. Around 800,000 years ago, we had our last flip. Prior to this, magnetic north hovered over Antarctica. Previously, scientists thought that this flip took centuries (some estimates suggested it could take as long as 7,000 years). They believed that this shift starts with the magnetic field weakening over the span of a few thousand years. Once this happens, the poles flip and the field springs back up to full strength again. However, a new study shows that the last time the Earth's poles flipped, it only took 100 years for the reversal to happen.
This is notable as, at present, the Earth's magnetic field is in a weakening stage. Scientists previously predicted that a flip could come within the next couple thousand years. It turns out that it might come a lot sooner. Data collected from a European Space Agency (ESA) satellite suggests the field is weakening 10 times faster than scientists originally thought. However, there is still a bit of uncertainty, as it is difficult to account for all factors.
For starters, geologists still don't know exactly what causes the planet's magnetic field to flip. Moreover, our planet goes through periods of "low points," where the field weakens and then returns to full force. As such, it is difficult to tell whether this is just a low point or the start of a flip. But in either case, the main point remains: These flips happen a lot faster than we thought.
The scientists were able to make this discovery by testing layers of ash deposited by volcanic eruptions over the course of 10,000 years. These layers were found in a lakebed near Rome. According to a release from Berkeley, the magnetic field directions are "frozen" into these layers of ash, which could be reliably dated to find out when the reversals occurred and how long they took to complete. Ash layers from long-ago volcanic eruptions are mixed into the sediment. The ash is made of magnetically sensitive minerals that hold traces of Earth's magnetic field lines, and the researchers were able to measure the direction the field was pointing.
The sediment layers also showed the magnetic field was unstable for about 6,000 years before the abrupt flip-flop. Moreover, the period of instability included two low points in the field's strength, each of which lasted about 2,000 years (so as was previously noted, it is difficult to know if the current weakening is a real flip or not).
What The Flip Means For Life On Earth
As previously mentioned, the rotation of our planet's iron core acts like a giant magnet and generates the magnetic field that envelops the Earth. We need this field because (occasionally) our sun will produce violent solar storms. Solar storms generally occur as a result of variations in the Sun’s magnetic field lines. When these field lines fluctuate, the matter they contain is released out into the solar system (and by “released,” I mean that it explodes from the Sun in a hellish firestorm). These super-heated particles blast from the Sun at speeds exceeding 600 miles per second (1,000 kms), and they can contain over 200 billion pounds of material (100 billion kilograms). This is bad news for anything that is in the path of the explosion.
Without Earth’s magnetic field, these cosmic storms would strip away our atmosphere, destroying our cellular structure and evaporating our oceans in the process.
However, there is no need for panic. If a pole flip did happen sometime soon, it could cause a few technical issues, but little else. Scientists have looked through the geological timeline for any evidence of catastrophes that might be related to a magnetic flip (like massive, radiation induced die offs). They haven't found any. This indicates that the field weakens, but not to dangerous levels. However, lead author, Paul Renne, stated that more analysis of the impact that this flip will have on life on earth, and on our civilization, is needed.
The new study will be published in the November issue of the Geophysical Journal International.