On September 1, 1859, miners woke up to another sunny day after the Colorado Gold Rush. Or so they thought. To their surprise, they soon discovered that it was actually 1 o'clock; And the sky was not illuminated by sunlight, but by brilliant curtains of light.
The Fiery Glow Could Be Seen As Far As The Caribbean
Leading people in many areas to believe nearby cities were on fire. But the real reason it became known as the Carrington Event was a solar storm—one of the largest in recorded history.
Solar storms are one of the many astrophysical phenomena caused by magnetic fields. These fields are generated by the movement of electrically charged particles such as protons and electrons.
For example, Earth's magnetic field is generated by charged molten metals circulating in the planet's outer core. Similarly, the Sun's magnetic field is generated by large convective motions in the plasma that make up the star.
As this plasma slowly rotates, it creates regions of intense magnetic activity called sunspots. Magnetic fields that form near these regions are often twisted and strained.
And when they are spread far enough away, they fall into simple configurations, releasing energy that launches plasma from the Sun's surface.
These Explosions Are Known As Coronal Mass Ejections
Plasma - made up mostly of protons and electrons - accelerates rapidly, reaching speeds of thousands of kilometers per second.
A typical coronal mass ejection travels the distance between the Sun and Earth in just a few days, flowing along the magnetic field that spreads through the Solar System.
And those that cross Earth's path are drawn to its magnetic field lines, which fall in the atmosphere around the planet's magnetic poles.
This tidal wave of high-energy particles excites atmospheric atoms such as oxygen and nitrogen, causing them to rapidly emit photons at different energy levels.
The Result is The Spectacular Light Show We Know As The Aurora.
And while this phenomenon is usually only seen near the Earth's poles, strong solar storms can bring particles of high enough energy to light up large swathes of the sky.
The magnetic fields in our solar system are nothing compared to the magnetic fields found in deep space. Some neutron stars produce fields 100 billion times stronger than those found in sunspots.
And the magnetic fields around massive black holes shoot out jets of gas that stretch thousands of light-years across. However, on Earth, even weak solar storms can be surprisingly dangerous.
Although storms that reach us are usually harmless to humans, high-energy particles falling in the atmosphere create secondary magnetic fields, which in turn create eddy currents that short-circuit electrical equipment.
During The Carrington Event
the only widespread electrical technology was the telegraph. But since then, we have become more dependent on electric-only systems. In 1921, another powerful solar storm burned out telephone and telegraph equipment around the world.
The entire railway system in New York was shut down and a fire broke out in the central control building. Relatively weak storms in 1989 and 2003 shut down areas of the Canadian power grid and damaged several satellites.
If we were hit by a storm as powerful as the Carrington event today, it could destroy our interconnected, electrified planet. Fortunately, we are not defenseless.
After Centuries Of Observing Sunspots
researchers have learned that the sun's normal magnetic activity follows an 11-year cycle, giving us an idea of when solar storms are most likely to occur.
And as our ability to predict space weather has improved, so have our mitigation measures. Power grids can be shut down in advance of a solar storm, while capacitors can be installed to absorb sudden surges of energy.
Many modern satellites and spacecraft are equipped with special shielding to absorb the effects of solar storms.
But even with these security measures, it's hard to say how useful our technology will be during the next big event. It's possible that we'll only have the aurora overhead to light the way ahead.
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