The Sun regularly hurls pieces of itself far larger than Earth straight at our planet. When one struck us in 1859, it didn't leave a crater—it set telegraphs on fire.
The Sun is not made of solid rock or liquid fire, but of plasma—a superheated, electrified gas. When the Sun’s intense magnetic fields twist, tangle, and snap, they violently fling massive amounts of this plasma into space in an event called a Coronal Mass Ejection (CME).
Right at the source, these eruptions dwarf our planet. A single solar prominence can extend hundreds of thousands of miles from the surface. By the time a CME travels the 93 million miles to Earth, the cloud expands to become tens of millions of miles wide, easily swallowing our entire planet as it passes.
Despite its monstrous size, the ejected material is incredibly diffuse. By the time it arrives at Earth, its density drops to just a few particles per cubic centimeter—emptier than the highest-quality vacuums created in laboratories. When this plasma cloud hits Earth, there is no physical impact.
Instead, a CME causes a magnetic collision. The charged particles carry their own magnetic field, which slams into Earth’s magnetosphere. This interaction funnels solar particles toward the poles, lighting up the atmosphere to create auroras. If the eruption is strong enough, it triggers a geomagnetic storm that induces powerful electrical currents in the ground. It was exactly this type of storm—the 1859 Carrington Event—that caused those nineteenth-century telegraph fires and generated auroras so bright that people could read newspapers at midnight. Today, a direct hit of that magnitude could overwhelm modern power grids and disrupt global satellite communications.