BY : SYED HASHIR (3M) ROLL NO. 70

AURORA

CONTENT : 1 . What is Aurora ?2 . What causes an aurora ?3 . Why do aurora come in different

colours ?4 . Where can you see an aurora ?5 . Do other planets have aurora ?6 . Why do we care about aurora ?

What is aurora ? It is a mysterious and un predictable display of light mostly in the night sky .

The name aurora come from roman Goddes of Dawn .

Aurora borealis - Northern light

Aurora australis – Southern light

What causes an aurora ?

The sun energy is carried towards the earth in the solar wind ,a stream of electricity charged particles (mostly protons and electrons) flowing out from the sun in all direction .

When this energy collide with earth’s magnetosphere(The region of space controlled by earth magnetic field) the magnetosphere losses its equiliberium .

What causes an aurora ? To become stable again the excess

energy is released suddenly, with much of energy going into accl. Of electron .

The electron which come from earth magnetosphere transfer their energy to oxygen and nitrogen atoms and molecules making them excited .

As the gas returns to their normal state , they emit photons, small burst of energy in the form of light and aurora is formed .

At altitudes of 100-400Km from earth surface .

Why do aurora come in different colours ?

High energy electron - oxygen - Green colour High energy electron - oxygen - Red colourNitrogrn generally gives of blue colour

Where can you see aurora ?

Aurora usually occur in the ring shaped areas about 4,000Km in dia. around the magnetic poles of earth .

Usually occur in north and south poles because electrons are guided towards poles by earth magnetic field .

Aurora Borealis – North Aurora

Aurora Australis – South Aurora

Do other planets have Aurora ? Jupiter,Saturn,Uranus – Observed

mercury , Venus, Mars – Not Observed

Because

Mercury do not have atm.

Venus and Mars do not have global magnetosphere

Why do we care about aurora ? The rapidly changing current can cause unwanted electric currents to flow through the long communication lines producing didruption in communication .

Radio signals are refracted

Ionosphere (the upper atm. ) become rippled like a cardboard

Electron accelerating to high energies in the tail of magnetosphere can raise havoc (wide spread disruption) with satellites , damaging electronics and creating false commands .

THANK YOU !!!