Most people think of space as an empty void, but in reality, space is a chaotic environment filled with plasma and magnetic fields. Between the planets lies a sea of charged particles continuously flowing from the Sun, known as the interplanetary medium.
As explained by Universe Today, in addition to solar plasma, the outer space environment is also filled with cosmic rays and fine dust particles. In fact, the interplanetary medium is constantly changing and can have significant impacts on our planet. These changes mean that outer space actually has weather.
With its constantly rotating surface, the Sun drives nearly everything in the solar system, and space weather is no exception. All of this sends material and radiation from the Sun’s surface towards the orbiting planets.
The most fundamental component of space weather is solar wind.
Earth is Continuously Affected by Solar Wind
The most fundamental component of space weather is solar wind, as explained by the University of Chicago, which is a continuous flow of hot particles that fills the entire solar system at a speed of about one million miles per hour. This wind originates from the solar corona. The Sun’s atmosphere is incredibly hot, reaching several million degrees.
However, solar wind is also not uniform. According to NASA, the charged particles that make up solar wind form loops and flows influenced by the Sun’s magnetic field, with varying intensities. The strongest winds can be found in regions known as coronal holes, where magnetic field lines are open and directed straight out from the Sun’s surface. With varying speeds and intensities, solar wind is responsible for most fluctuations in space weather as it collides with Earth’s magnetic field.
Just like weather in Earth’s atmosphere, space weather even has severity scales similar to those used for classifying storms and earthquakes. These scales indicate that the strongest space weather events can destroy satellites, affect navigation systems, and even pose radiation risks to aircraft.
The Largest Structure in the Solar System is an Invisible Structure
According to Space.com, the Sun creates a gigantic bubble in space. Known as the heliosphere, it is filled with solar wind, protecting the entire solar system from harmful interstellar material. Inside the heliosphere, solar wind is influenced by the magnetic field.
In fact, the charged particles of solar wind carry the Sun’s magnetic field with them as they flow outward into space. This results in an invisible magnetic sheet filling the entire solar system.
The Sun oscillates between mild and violent extremes.
The Sun Has an 11-Year Weather Cycle
Almost all fluctuations in space weather originate from the Sun, but solar activity also changes over time. The solar cycle averages about 11 years, indicating that the Sun oscillates between mild and violent extremes.
As explained by Space.com, since December 2019, the Sun has been in its 25th solar cycle, although the exact duration can be difficult to predict as cycles can last anywhere from 8 to 14 years. This is caused by changes in the Sun’s magnetic field and active periods known for significant increases in sunspots on the Sun’s surface.
The more twisted, chaotic, and active the Sun’s magnetic field, the more likely sunspots will appear. According to a study published in the journal Astronomy & Astrophysics, sunspots are the result of strong magnetic field lines penetrating the Sun’s surface. This blocks the flow of plasma within the Sun, causing streaks of cooler, darker material.
In each cycle, solar activity transitions from a quiet period – solar minimum – to the most active phase – solar maximum. However, the exact level of activity for each cycle can vary significantly.
The Van Allen belts are too far from Earth to be dangerous.
Earth is Surrounded by Trapped Solar Wind
Earth’s magnetic field sweeps the solar wind, preventing most of it from colliding with our atmosphere, but it also traps a significant amount of wind in Earth’s orbit. As a result, two vast regions of space form around Earth, filled with dangerous charged particles. As explained by the Houston Space Center, these are known as the Van Allen radiation belts, which, although invisible, are hazardous.
The Van Allen belts are too far from Earth to pose a danger to most astronauts (technically, the International Space Station still resides within Earth’s upper atmosphere, according to NASA), but they are a concern for a specific group of astronauts – the NASA Apollo crews. Forbes explains how careful NASA scientists had to be to keep astronauts safe during these missions.
However, the Van Allen belts can still pose problems for spacecraft in lower orbits. Space weather can affect Earth’s magnetic field. A study in the journal JGR Space Physics refers to these events as Van Allen belt breaches, which can be caused by fast solar wind or coronal mass ejections from the Sun, causing the belts to generate high-energy electron showers towards Earth several times a year.
