What Will Happen When Earth’s Magnetic Poles Reverse?


Hey there and welcome to Life Noggin! Our Earth is pretty awesome. It’s basically a spinning rock flying through
space, carrying humans, animals, and friendly animations with it. And it also has a magnetic field that protects
us from radiation from space and coronal mass ejections from the Sun. And the Earth has had this magnetic field
for millions of years. You can think of the Earth as a giant bar
magnet, where the magnetic field lines go from magnetic north to south. Currently, the magnetic north pole is near
the geographical north pole and likewise for the south. So, if your body is pointed north, a magnetic
compass in your hand would be pointing north too. But it hasn’t always been that way. In fact, around 800,000 years ago, if you
were facing north, the compass needle would point to the south. In other words, the magnetic field was reversed. But how? This is actually something that happens relatively
often…well, often relative to the age of the universe. See, for the past 20 million years or so,
the Earth’s magnetic field reverses about once every 200,000 to 300,000 years. But it’s been about 780,000 years since
the last time the field reversed. However, when it does happen, it doesn’t
just reverse instantaneously — you won’t walk outside one day and Google maps will
have no idea which direction is which. Instead, this reversal takes hundreds, if
not thousand of years to do. And recent research by the ESA shows that
the Earth’s magnetic field is weakening at a rate ten times faster than they previously
thought — about 5 percent per decade — which is a sign that the magnetic field may be starting
the process of reversing. And it’s possible that this reversal may
even happen within some of our lifetimes. But before you panic, don’t worry, we’re
not all going to die because of this. There isn’t any evidence to suggest that
magnetic field reversals in the past have led to any mass extinctions. And even if the magnetic field does continue
to weaken, we still have the atmosphere to protect us from some harmful radiation. The main concern is that power grids and communications
systems may be at risk. And also, any animals that use the magnetic
field to navigate — like pigeons — might be a little confused for a while. Heh…look at that poor pigeon go. But why does this reversal even happen in
the first place? Well, the reason that the Earth even has a
magnetic field has to do with the molten iron in the outer core. And the motion of that molten iron, along
with some complicated physics, generates a magnetic field through something called the
dynamo effect. And for reasons still unknown to scientists,
the molten iron’s motion must somehow change to reverse the magnetic field. It’s not an incredibly satisfying answer,
but hey, that’s why we have scientists researching the topic! But rest assured knowing that you aren’t
in danger if the magnetic field reverses anytime soon. After all, it could be in your lifetime, or
a thousand or more years from now. Only time will tell. Speaking of time, do you think you could survive
2.5 million years ago? Check out this video. There’s a link in the description if you’re
on mobile. Make sure you come back every Monday for a
brand new video. As always, I’m Blocko and this has been
Life Noggin. Don’t forget to keep on thinking!

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