What are aurora australis and aurora borealis? How are these triggered? (Answer in 250 words)

Introduction

Auroras are luminous displays in the upper atmosphere produced by interactions between charged solar particles and Earth’s magnetic environment.

Types

• Aurora borealis is the northern lights, visible mainly at high latitudes around the Arctic.
• Aurora australis is the southern lights, visible around the Antarctic and high southern latitudes.
• Colours depend on atmospheric gas and altitude: oxygen commonly produces green and red, while nitrogen contributes blue and purple hues.

How they are triggered

• Solar wind and coronal mass ejections carry energetic electrons and ions toward Earth.
• Earth’s magnetosphere guides particles along magnetic field lines toward polar ionospheres.
• Particles collide with oxygen and nitrogen atoms, exciting them; light is emitted when they return to lower energy states.
• Geomagnetic storms intensify auroras and can disrupt satellites, radio, navigation and power grids.

Significance

Auroras reveal solar-wind dynamics and magnetosphere-ionosphere coupling, linking space weather to technological risk on Earth.

Keywords: solar wind, magnetosphere, ionosphere, coronal mass ejection, geomagnetic storm.