On September 18, 1941, the Brooklyn Dodgers were in Pittsburgh to play a game against the Pirates. In the fourth inning, with the score tied 0-0, announcer Red Barber’s radio broadcast was disrupted, and listeners suffered 15 minutes of silence. When the broadcast resumed, the Pirates had scored four runs. In a tight World Series race, Dodgers fans were irate and called the radio station to complain. 

Thousands of baseball fans had experienced the practical effects of a geomagnetic storm in Earth’s atmosphere that began with a plasma eruption 93 million miles away, on the surface of the Sun. But excuses of sunspots and magnetic disturbances did not temper the frustrations of Dodger fans who saw their team go on to lose to the Pirates, 5-6. Nor did the magnificent red, purple, and green light show that lit up the sky from Maine to Florida. Lights of the aurora and blackouts from radio communications are only a few of the effects we experience from this phenomenon we call space weather.

Sun-Earth Interaction

Our Sun is a huge ball of gas and plasma that churns on the visible surface, much in the same way that water boils in a pot. That rolling motion creates complex magnetic fields that can produce sunspots, areas slightly cooler than the surrounding areas on the Sun. These active regions of magnetic activity can also create solar flares—huge explosions that release electromagnetic energy, such as radio waves, X-rays, and ultraviolet radiation, into space. The Sun can also eject part of itself, an event called a coronal mass ejection, and that material can sometimes head towards Earth.

The Sun and Earth are constantly interacting. The Sun provides warmth and light and the Earth’s magnetic field protects us from the Sun’s more dangerous radiation. But extreme events on the Sun can create space weather—major disturbances in the bubble around the Earth where the Earth’s magnetic field dominates. 

On September 10, 1941, a group of sunspots formed near the eastern limb of the Sun and slowly revolved with the Sun until they faced towards the Earth. The sunspots were extraordinarily large, even visible with the naked eye alone (with eye protection, of course!). From these observations, scientists warned radio operators that they could experience major disruptions in the coming weeks. On September 17, a week after, scientists observed a solar flare, and less than a day later they reported the arrival of a coronal mass ejection, creating a major magnetic storm on Earth.

Impacts On Earth

Space weather has always been with us, most noticeably observed in the aurora around the north and south poles. But we have become more vulnerable to what’s happening in Earth’s atmosphere and in space as we’ve relied more on electrical systems and electronics. 

When material from the Sun nears Earth, it gets pulled along Earth’s magnetic field, funneling plasma and charged particles towards the northern and southern poles. That light and material interact in the Earth’s upper atmosphere to produce an extravagant light show. Auroras are typically only seen near the poles, but the September 1941 storm was so great that people in Canada and much of the United States witnessed this auroral light. 
    
Space weather can also cause power outages. This happens when geomagnetic activity creates a change in the electric fields in Earth’s crust. While no power outages were reported in 1941, as a result of this storm, power companies experienced variations in the voltages across power lines.

The first televised professional baseball game was in 1939, but by 1941, there were still fewer than 10,000 households with a television set. Most Americans still relied on the radio to keep up with their favorite baseball team. Radio used the high ionospheric layer of Earth’s atmosphere as a reflector. Solar activity, such as flares and coronal mass ejections, disrupt the reflecting layer and create radio fadeouts.

Predicting Space Weather

The impacts of the 1941 storm were minor compared to what it possible with a larger geomagnetic storm. Today, the Space Weather Prediction Center (SWPC), is responsible for monitoring and forecasting disruptions to Earth’s space environment and magnetic field. Using a series of sun-observing satellites in space, SWPC gathers data on the Sun’s activities and predicts possible impacts to Earth. 

Many groups use SWPC’s forecasts to protect people and equipment. During a strong solar storm, there is a greater chance that astronauts aboard the International Space Station (ISS) will be hit with damaging radiation. NASA monitors radiation exposure possibilities and can direct astronauts to hunker down in areas of the ISS that are better shielded from radiation. The Federal Aviation Administration (FAA) monitors possible loss to radio communications for commercial airplanes on routes close to the poles. Pilots can be instructed to divert flights if needed. Space weather can hinder operations of satellites in space, damaging solar panels and degrading electronics. A forecasted geomagnetic storm can alert satellite operators to put satellites in a “safe mode,” avoiding the worst potential harm to the system.

As we become more reliant on space-age technology, our ability to understand and predict space weather becomes even more important.