What is space weather?
Just as weather on Earth describes changing conditions in our air, space weather describes the changing conditions in space around Earth. It is driven almost entirely by the Sun. The Sun constantly sends out a stream of tiny charged particles called the solar wind, and sometimes it releases sudden bursts of energy and matter that reach Earth.
Key idea
Space weather is caused by solar activity. When the Sun is more active, space weather is more intense, and its effects on Earth's technology become stronger.
Storms from the Sun
Two important events create rough space weather. A solar flare is a sudden, powerful burst of radiation from the Sun's surface. A coronal mass ejection (CME) is a huge cloud of charged particles thrown out into space. If this material is aimed at Earth, it can arrive in one to three days and disturb our planet's surroundings.
Luckily, Earth is not defenceless. Our planet's magnetic field forms an invisible shield called the magnetosphere. It deflects most of the charged particles around the planet, protecting living things on the ground.
Effects on Earth
Example
When particles from the Sun follow Earth's magnetic field toward the poles and strike gas in the upper atmosphere, they make the sky glow. This beautiful light is called an aurora, seen near the north and south poles.
Strong space weather can also cause problems. It can damage satellites, disrupt radio and GPS signals, and even overload power grids, causing blackouts. Because we depend so much on technology, scientists monitor the Sun carefully to give warnings.
Remember
- Space weather comes from the Sun, not from Earth's own weather.
- Earth's magnetic field protects us from most solar particles.
- Auroras appear near the poles.