What are auroras? What are northern and southern lights?

Why in News?  Recently, the night sky was lit up by northern lights, or aurora borealis, at Hanle village in Ladakh early . Northern lights were also witnessed in other parts of the world, including in the United States and the United Kingdom. Meanwhile, southern lights, or aurora australis, were spotted in countries such as New Zealand and Australia.

What are auroras?

• Auroras are essentially natural lights that appear as bright, swirling curtains in the night sky and can be seen in a range of colours, including blue, red, yellow, green, and orange.
• These lights primarily appear near the poles of both the northern and southern hemispheres all year round but sometimes they expand to lower latitudes .
• As mentioned before, in the north, the display is called the aurora borealis; in the south, it is known as the aurora australis.

What causes Auroras?

Sun’s Activity: The sun constantly emits a stream of charged particles called the solar wind. Sometimes, the sun has bursts of intense activity called solar storms, which release even greater amounts of these particles.

Earth’s Magnetic Field: Our planet is surrounded by a magnetic field that shields us from most of the sun’s particles. However, the field is weaker at the poles.

Particles Collide with Atmosphere:  When a solar storm hits, some of the charged particles travel down the magnetic field lines towards the north and south poles. These particles collide with atoms and molecules in Earth’s atmosphere, causing them to get excited.

Light Show: As the excited atoms and molecules relax back to their normal state, they release energy in the form of light, creating the colorful auroras. The color depends on the type of gas molecule that was struck. Oxygen glows green and red, while nitrogen gives off blue and purple hues.