IMG_1815.jpeg

# Polar Auroras **6.4 Polar Auroras** Have you ever seen the Northern Lights? These beautiful lights, called auroras, are produced by a phenomenon known as solar wind. **6.4.1 What is Solar Wind?** * Nuclear reactions within the Sun release a huge amount of energy. * This energy forms bubbles on...

# Polar Auroras **6.4 Polar Auroras** Have you ever seen the Northern Lights? These beautiful lights, called auroras, are produced by a phenomenon known as solar wind. **6.4.1 What is Solar Wind?** * Nuclear reactions within the Sun release a huge amount of energy. * This energy forms bubbles on the surface of the Sun. * Charged particles escape the Sun's gravity, creating solar wind. * Solar wind is a stream of small particles emitted from the Sun. **6.4.2 What are Polar Auroras?** Polar auroras occur when solar wind particles collide with particles in Earth's atmosphere. * When this happens at the North Pole, it's called aurora borealis (Northern Lights). * When it happens at the South Pole, it's called aurora australis (Southern Lights). **How are Polar Auroras Produced?** * When the Sun is active, it releases more solar wind particles than usual. * Earth's magnetosphere, a protective shield, handles the excess particles near the poles. * At the poles, the magnetic field lines on Earth enter and exit Earth's core. * The solar wind particles collide with the atmosphere, creating beautiful colors. **Colors and Appearance** * Polar auroras are usually blue-green or sometimes yellow. * Their colors can range from red to purple. * Their shapes are constantly changing and can appear as clouds, curtains, arcs, or rays. * They occur high up in Earth's atmosphere, above 90 km. **Seeing the Northern Lights in Quebec** * The Northern Lights (aurora borealis) are visible almost every night in northern Quebec (Nunavik). * Further south in Quebec or Montreal, they may only be visible 1-3 times per month. * Checking the Canadian Space Agency's website provides alerts about the best viewing locations for auroras. **Diagram of Earth's Magnetosphere** **(Refer to the diagram on the previous page to visualize the schematic of Earth's magnetosphere.)** This diagram shows how solar wind is deflected by the magnetosphere, with special focus on the interaction near the poles. **Important Concepts** * **Solar Wind:** A stream of particles from the Sun. * **Magnetosphere:** A protective shield around Earth, created by Earth's magnetic field. * **Thermosphere:** The layer of Earth's atmosphere where polar auroras form. * **Aurora Borealis (Northern Lights):** Polar auroras observed in the Northern hemisphere. * **Aurora Australis (Southern Lights):** Polar auroras observed in the Southern hemisphere.