The South Atlantic Anomaly

Transcript

For years people believed that there was a part of the Atlantic Ocean where ships and planes would disappear called the Bermuda Triangle. It turned out that ships and planes didn’t disappear there at any higher rate than they did elsewhere, and it just wasn’t a thing.

However, researchers did find a place where the vessels which traveled into it had a far higher rate of catastrophe.

This area was in outer space.

Learn more about the South Atlantic Anomaly, the spacecraft killing zone of outer space, on this episode of Everything Everywhere Daily.

Ever since Sputnik was launched into Earth orbit becoming the first artificial satellite, we have had to deal with the issue of satellite failure. This isn’t really a mysterious phenomenon.

Satellites require energy, and if they are battery powered they will eventually run out of power. Even if they have solar panels, they need batteries for when the satellite is on the dark side of the Earth, and batteries, just like in your smartphone, degrade in performance over time.

Space is also just a very harsh environment. You have extremes in temperatures, exposure to a vacuum, and you can collide with very small particles called micrometeors at very high velocity, which can do a lot of damage over time.

So, when a satellite fails, it isn’t totally unexpected.

However, as we put more satellites into space and gathered more data, a pattern began to appear. A very puzzling pattern.

A large number of satellites all experience problems, or failed, in the same region above the Earth. It didn’t matter if it was day or night, or where that part of the Earth was pointed, something was happening in that spot.

That area was above South America and a large part of the South Atlantic Ocean.

It was dubbed the South Atlantic Anomaly, or as it is sometimes known, The Bermuda Triangle of Space.

Just to give you an idea of some of the high profile problems which have occurred over this spot.

In 2016, Japan’s Space Agency lost their X-ray Astronomy Satellite called Hitomi over the anomaly. The system which orientated itself had problems when flying through the anomaly, and it is believed that instead of just rotating the satellite, when flying through the anomaly it might have just spun itself to death and self destructed.

In 2007, Globalstar which is a company with a fleet of voice and data satellites, lost several satellites after the electronics on board degraded after frequent trips through the anomaly.

The recent Space X Dragon crew module suffered computer problems when flying through the anomaly on the way to the International Space Station.

Speaking of which, the ISS, the Space Shuttle, and Skylab from the 1970s all experienced computer and electronic problems while over the South Atlantic.

Astronauts have recorded seeing white lights flash before their eyes when traveling through this region.

So what is happening? Is it some rogue government shooting death rays into space? I’m not saying its aliens, but might it be aliens?

Actually the explanation for what is happening in the South Atlantic Anomaly can all be explained by science.

Understanding the anomaly starts with an understanding of the Van Allen Belt.

The Van Allen Belt was discovered by its namesake, Dr. James Van Allen of the University of Iowa. The belt is an area of high radiation which surrounds the Earth.

An incredible number of charged, energetic particles are shot at the Earth from the Sun. If you remember back from my episode explaining radiation, radiation is nothing more than high energetic subatomic particles and photons.

As the particles are sent towards the Earth, they are deflected by the Earth’s magnetic field. Our magnetic field is what prevents most of the radiation in space from reaching the surface of the Earth. If it didn’t exist, life on Earth would look very different.

When these particles are deflected away, they have to go somewhere, and many of them wind up trapped in the Van Allen Belt.

The discovery of the belt was in 1958 with the launch of the very first American satellites.

The Van Allen Belt extends from roughly 640 to 58,000 kilometers or 400 to 36,040 miles above the surface of the Earth.

For the most part, the belt is above the altitude where most low Earth Orbit satellites are positioned. For example, the ISS orbits at an altitude of about 254 miles above Earth.

OK, so if this is a belt around the entire Earth, what is so special about the spot over the South Atlantic?

Well, as it turns out, the Earth magnetic field isn’t perfectly smooth or symmetric.

The magnetic field is created by the iron in the liquid core of the Earth. It is constantly moving and changing slowly over time. This is why the magnetic north and south poles are constantly changing every year.

It turns out that the South Atlantic Anomaly is basically a dimple in the Earth’s magnetic field. In that spot, the magnetic field is weaker than it is anywhere else on Earth.

Because the magnetic field is weaker, the Van Allen Belt dips down to its lowest point of around 200 kilometres or 120 miles above the surface of the Earth.

When satellites fly through that region, they are being exposed to far higher radiation than they are anywhere else in orbit.

This is why computer equipment tends to fail when it flies through that region. The highly energetic particles can damage circuits and electronics causing failure.

It is also the explanation as to why astronauts would see flashing lights when they flew through the anomaly. The radiation was literally hitting their retinas causing their eyes to see flashes of light.

So, what can be done about the anomaly?

Well, it depends on the spacecraft. When the Hubble Space Telescope flies through the anomaly, they just don’t take observations. Ever. The radiation would cause problems with the electronic sensor, so they just never make observations in that region. It is actually something they have to really pay attention to because it will fly through the anomaly several times a day.

Other satellites either have to do that same thing, and shut off some of their important electrical system when they fly through, or they need to design the satellite with extra shielding to protect themselves from the radiation.

As for humans, the best you can do is provide extra shielding, which is what they have on the International Space Station. The crew quarters and other places where astronauts spend most of their time will have extra shielding to protect them.

The anomaly itself is slowly changing. It is moving about 12 miles per year to the east, and it might slowly be dividing into two separate anomalies, or one anomaly with two lobes. This is all due to changes deep in the Earth’s core, which are reflected in the magnetosphere in space.

Using paleomagnetic evidence, geologists have determined that the anomaly has been there for at least a million years and it is very slowly getting weaker.

In fact, some speculate that the anomaly might be the first stages of the reversal of the Earth’s magnetic poles, which happens approximately every 450,000 years, and we are well overdue.

So, there isn’t a whole lot you can do about the anomaly other than be aware of it and prepare for it. It is slowly changing, but not so fast that it will make a difference within our lifetimes.

So, unlike the real Bermuda Triangle, the one in space is no mystery. It can all be explained by science.