FLare

A large solar flare in comparison to the size of the Earth. Credit: NASA

Well, what’s happening on the Sun? That’s the question astronomers are puzzling over. As we were all enjoying another glorious spring weekend across Australia, a powerful X-class flare, one of the biggest you can get, ripped through the Sun’s lower atmosphere and sent a blast wave directly toward Earth.

It hit us early Saturday morning travelling at over 1400 kilometres a second. All across the globe, in the higher latitudes, people were reporting beautiful auroral activity, those amazing ribbons of light that dance across the night sky.

Flares of this size can cause power station failures, blackouts and electronic communication problems. Airline companies who rely on GPS satellites for global positioning are most at risk because solar flares have been known to knock their satellites out of commission.

Safe image projection using a telescope or binoculars. Cr. Swansea Astro Soc.

The amount of energy released by a flare can be equivalent to millions of hydrogen bombs exploding at the same time – ten million times greater than that released by a volcanic eruption. What causes a solar flare? It’s when magnetic energy that has built up is suddenly shot out into space, mostly around sunspots. This flare was around 100,000 kilometres long!

Watch for more news of flares because right now the Sun is going through a period of heightened activity. Astronomers call it the ‘Solar Max’ and it occurs every 11 years. You can see sunspots, but not directly, even glimpsing the Sun directly can damage your eyes,

The simplest safe method of looking at the sun is to watch the Sun’s image projected onto a piece of paper. Poke a small hole in an index card with a pencil point, face it toward the Sun, and hold a second card about a meter behind it in its shadow. The hole will project a small image of the Sun’s disc onto the lower card.

You can use binoculars or a small telescope to project an image of the Sun onto a screen or white sheet of paper but don’t look into the eye end! Instead, let the sunlight fall onto the paper behind where you normally look through. You’ll see a neat image of the Sun and sunspots – then listen for the cries of Wow!

On September 23 in Australia we experience the Spring Equinox, the Earth’s poles are the same distance from the Sun but remember, temperatures on our planet are not determined by the distance of the Earth from the Sun. Rather it is the angle of the Sun’s rays striking the Earth.

In Summer, the Sun is high in the Sky and the rays hit the Earth at a steep angle. In winter, the Sun is low in the Sky and the rays strike the Earth at a shallow angle.

The seasons are governed by the tilt of the Earth’s axis in space as it journeys around the Sun in a year. When the South Pole of the Earth is tilted towards the Sun, this is our Summer. Six months later, when the South Pole is tilted away from the Sun, it’s our Winter. In between these we have Autumn and Spring. Enjoy it!