How it happens

Streams of charged particles continually flow out from the sun, known as solar wind. Earth’s magnetic field deflects most of the solar wind away, but the magnetic field catches some particles in the plasma gale. These high-energy charged particles travel along the magnetic field lines to Earth’s poles

and plunge into the atmosphere, smashing into oxygen and nitrogen atoms.

The collisions excite the oxygen and nitrogen, giving the atoms extra energy. But excited atoms are not stable and quickly relax into a non-excited, or ground, state, releasing energy in the form of light particles, or photons. These photons make up the auroras.

Auroral shades

An aurora’s colour depends on the energy of the incoming charged particles and the type of gas particles that are colliding. Low-energy particles colliding with oxygen atoms at high altitudes, above 240 kilometres, make the oxygen atoms glow red.

A pale yellowish-green glow is produced by oxygen molecules about 100km above the earth. Rare, all-red auroras are produced by high-altitude oxygen, at heights of up to 320km. Nitrogen produces blue or purplish-red aurora.

More energetic particles slam into oxygen at lower altitudes, around 100 kilometres to 240 kilometres above Earth. Due to the incoming particles’ higher energy, they cause oxygen atoms to emit higher frequency light. It appears green.

The Auroral shapes

Auroral displays appear in many forms and shapes. Their features depend on conditions of both the atmosphere and Earth’s magnetic field. They can appear as patches or scattered clouds of light to streamers, arcs, rippling curtains or shooting rays, lighting up the sky with an eerie glow.

One common auroral form is a tall curtain of light, which trace particles raining in from space. The particles are drawn down by disturbances in Earth’s magnetic field called Alfvén waves.

What are auroras?

Auroras are lights that dance across the sky above Earth’s poles in two oval-shaped zones. They are the result of collisions between gaseous particles in the Earth’s atmosphere with charged particles released from the sun’s atmosphere.

The northern lights, or aurora borealis, are most visible in Alaska and Canada. The aurora borealis also shimmers above Greenland, Iceland and Norway. The southern lights, or aurora australis, can be seen over Tasmania, New Zealand and Antarctica.

Paralysed puppy can go for walks again!

Aparalysed puppy has taken her first walk in her new wheelchair after £7,000 was raised on GoFundMe to pay for it.

Pumpkin, the West Highland terrier, was born paralysed in her two hind legs and could only move by dragging her body forward, using her front paws.

Foster mum Tammie Fox started a fundraiser for treatment which has raised thousands and bought a wheelchair from disabled dog charity Winston’s Wheels.

Pumpkin is now happily moving around, finally able to run and go for walkies.

A breeder surrendered pumpkin to charity Breeds in Need, and Tammie took in the pooch, aged 10 weeks. Future treatment for Pumpkin is expected to cost up to £3,000, plus travel costs.

Published in Dawn, Young World, November 6th, 2021