Last year I wrote a post about how the earth’s poles are switching. The few pieces of feedback I received were along the lines of:
Wtf are you talking about, Jeff?
There is no way this is true and even if it is I don’t care, please go back to writing about baseball.
Even my grandmother got in on the action:
Well, it’s been a year, so I thought I would give an update.
As a reminder, the earth’s magnetic field can change at any time. On average, it happens about once every 500,000 years. The reversal itself isn’t the problem, it’s the transition. During the process of reversal, there is a stretch of time between 100 and 1,000 years where the magnetic field is reduced to about 5% of its normal strength. And since humans rely on the magnetic field for protection from solar radiation, this can … uh … be a problem. In fact, scientists believe that past flips have led to mass extinctions.
So what actually causes these reverals? Here’s a quick explanation:
The Earth’s magnetic field is generated by the movement of molten iron in its outer core, through what’s known as the dynamo theory. We won’t know for sure until we actually get down there and do some investigating, but as far as scientific theories go it’s pretty well grounded.
Due to reasons we don’t fully understand, something causes the movement of the molten core to change — and thus the north and south poles switch. The most likely reason for the reversal is simply the general interaction and chaos of the massive dynamic forces at play — but there are some other hypothesized triggers, such as massive impacts, or significant plate tectonic shifts.
Now that you are thoroughly scared, let’s look at the facts.
It is true that the earth’s magnetic field – which extends 370,000 miles above the surface – is already starting to weaken, particularly over the Western hemisphere. However, it is also true that the field is strengthening in other parts, particularly over the southern Indian Ocean. Still, data suggests that the total field is weakening at about 5% per decade, a lot faster than previously thought.
It is not necessarily true that this will lead to mass extinction and certain death for the human race. While there seems to be a correlation to past extinctions, it could also be true that those extinctions were caused by something else – an asteroid impact, a nearby supernova, a gamma ray burst*, a solar flare, a black hole, aliens.
*A gamma ray burst is one of the most powerful events that can occur in the universe. It happens when a star’s core fuses into heavier elements until it eventually cant fuse anymore. And then what happens? Well, it collapses into a black hole, of course. In the process, it releases more energy in a few seconds than the sun will over its 10-billion-year lifetime. Gamma ray bursts are rare – in our galaxy, they’ll only happen in a few times in a million years – but it could really ruin our day if it happens to be pointed in our direction.
So … with regard to the poles, has anything changed in the past year? Eh, not really. Scientists still believe we are in the process of a magnetic reversal. Scientists are still unsure whether the result will be catastrophic (mass extinctions) or hardly noticeable (power grids are slightly affected).
It is pretty amazing that the universe allows us to live, considering everything that could go wrong. No black holes or asteroids or gamma ray bursts or solar flares in recent memory. No super-volcano eruptions that have caused a nuclear winter. No alien abductions. No super-viruses. No nuclear warfare. And for that I say: well done, everyone. Let’s keep it going for as along as possible.