For decades, scientists have watched our resident star go through violent fits, projecting charged particles and whips of brilliant gas out into space. Like a string of volcanic eruptions on a colossal scale, our sun puts on an incredible stellar light show day in and day out, but one element of its repertoire has had astronomers scratching their heads for decades. Among the arcs of fire and pillars of million-degree gas lie the breeding grounds for something far more strange.
The Solar System’s Biggest Lava Lamp
The sun is a massive nuclear furnace whose core burns at a staggering 27 million degrees. Its surface, by comparison, is only about 10,000 degrees. The heat differential creates convection currents within the star, where hotter material from the center of the sun rises to the surface, and denser, cooler material from the surface sinks back down toward the core. On the surface, further differences in temperature cause a dizzying array of reactions where warmer and cooler pockets mix and hot spots eject bursts of charged particles into space. This turbulence occasionally allows for the formation of massive plasma bubbles that can be up to 500 times the size of Earth.
Astronomers studying solar activity have determined that these blobs, called periodic density structures, form in the sun’s corona. They’re made of charged particles, and they appear to form at somewhat regular intervals, dictated by the sun’s surface activity. When solar winds kick up, they can form eddies that gather blobs of charged particles. The density of these swirling masses increases to form a periodic dense structure before being kicked out into the solar system where they travel millions of miles before dissipating.
Bubbles Of Doom?
As horrifying as giant tumbling orbs of plasma sound, the danger presented by these roiling masses is relatively small. Despite being tens to hundreds of times the size of our planet, periodic dense structures are mere bubbles of ionized particles. They also don’t travel outward from the sun in a ring. For one to even come close to Earth, it has to first be on a collision course with the planet, which isn’t a guarantee. When they do line up with our trajectory, it’s not much different from being brushed by a solar storm. Earth’s magnetic field dissipates any charged particles it comes in contact with until the bubble has passed, taking the particles with it.
At worst, one of these periodic dense structures could knock out power grids, and at best, they could result in some beautiful auroras. Although their description sounds like a deadly weapon straight out of science fiction, they’re no more harmful than any other burst of radiation from the sun. Diagrams of the solar system make it seem like one of these massive blobs of plasma would have a hard time missing us, but there is so much space between the sun and Earth, even something 500 times the size of our little planet would be more likely to miss us than it would be to hit us.
A Lot Of Hullabaloo
Although astronomers have been gathering data on these bizarre storms for the past 11 years, they’ve only just been able to release their findings. The sun experiences “seasons” of a sort. Electromagnetic activity on the sun’s surface runs in 11-year cycles, and scientists had to track the progress of these periodic dense structures throughout a cycle to even begin to understand them. They’ve determined that the plasma bubbles form more often during peaks in solar activity and less during calmer periods. Studying their formation processes over further cycles will help us understand more about how they come to be and allow us to potentially predict their formation in the future.