illustration of Earth's magnetosphere

Earth’s magnetosphere cracked under pressure

Contributed by
Dec 7, 2016

Plasma bursts. Total radio blackouts. Auroras flashing in space like cosmic Christmas lights. If all this galactic chaos sounds eerily enough like a studio brainstorming session for the next Ridley Scott movie, it could be—but it actually happened.

The most epic disaster movie that never existed was captured by the GRAPES-3 muon telescope at the Tata Institute of Fundamental Research in Ooty, India. The opening scene was a coronal mass ejection. Plasma spewing from the solar corona, that glowing halo of ionic violence surrounding the sun, zoomed toward Earth at over 2,000 times the speed of sound. When the force of the impact on our magnetosphere compressed it to less than half its million-kilometer radius, it literally cracked under pressure. This phenomenon roused a beast of a geomagnetic storm so monstrous, it splashed the northern sky with rainbows of aurora borealis and made sure no one in the the uppermost latitudes would be tuning in to the radio anytime soon.

“The simultaneous occurrence of the burst in all nine directions suggests its origin close to Earth,” says Dr. Pravata K. Mohanty, who studied this phenomenon at the Tata Institute with his astrophysicist colleagues . “It also indicates a transient weakening of Earth’s magnetic shield.”

GRAPES-3 muon telescope

Think of the magnetosphere as an invisible shield that defends our planet from showers of harmful cosmic rays issuing from the sun and other stars. It is an expanse of space surrounding our planet in which charged particles are manipulated by Earth’s magnetic field (generated by electrical currents around its liquid metal core), and usually deflects these death rays. Unfortunately, even such a superpowered line of defense isn’t invincible. Data from GRAPES-3 indicates that the fissure which set off all sorts of pseudo-apocalyptic phenomena is the result of magnetic reconnection. When electrically conductive plasmas warp the magnetosphere and convert magnetic energy into thermal and kinetic energy, it’s about as close to anarchy as you can get at the molecular level.

Geomagnetic storms can do much worse than disconnect the classic rock station. They wreak havoc on anything electrical even if you don’t see sparks flying from the phone lines like they would in some epic sci-fi catastrophe scene. These storms can also mess with pipelines and throw planes, ships, satellites and even your car’s GPS off course. While this means migraines for astronomers and air traffic controllers, can it really suck your Caribbean cruise into the gaping chasm of the Bermuda Triangle? Probably not. Humans are also at risk for radiation poisoning from a disruption in the magnetic field, though this potentially lethal threat to astronauts is highly unlikely for those of us who are earthbound.

While the magnetosphere did self-heal like something out of science fiction, this wasn’t before a sprinkling of particles from cosmic rays (hardly as glittery as it sounds) floated through the crack into our atmosphere. GRAPES-3 interpreted these particles as evidence of a solar burst when Earth’s magnetic field started acting strange and bent them across every time zone. Mohanty and his colleagues remain excited about and what this phenomenon can tell us, hinting that “[it] may hold clues for a better understanding of future superstorms that could cripple modern technological infrastructure on Earth, and endanger the lives of the astronauts in space.”

Meaning, the analysis of data from cosmic monitors like GRAPES-3 could influence more advanced protection measures in the face of an impending solar storm, and keep disaster movies where they belong—on DVD. 

(Via Science Daily)

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