BRIGHT LIGHTS: Aurora Australis, or the "Southern Lights", glow in the sky over the town of Glen Oroua near Palmerston North, on April 1, 2001.

A large "blob" of supercharged solar gas is hitting the Earth around now but one of the country's leading astronomers says it is nothing to fear.

Canterbury University astronomer Alan Gilmore of the Mt John University Observatory at Lake Tekapo said people toward the southern end of the country might get a dramatic display of aurora australis or "Southern Lights" tonight.

Did you see the aurora? Click here to send us your images

"Assuming the sky is clear tonight we might have one, we will certainly be looking out for it."

But he cautioned against alarm, saying it was nothing to get "over excited" about.

Mr Gilmore said the data coming in from satellites indicated that massive sun flares have sent a wave of solar supercharged gas toward Earth.

It was not possible now to say whether there would be an aurora yet.

If it did occur and it was a strong aurora he said it was possible radio communications could be disrupted and international authorities would be worried about the safety of satellites.

Aurora australis, or the "Southern Lights", are common in the southern hemisphere and included a spectacular display across parts of New Zealand in April, 2001. The sky over the South Island also treated stargazers and photographers to a magical display of aurora australis in April this year.

NASA's Solar Dynamics Observatory says Earth's natural magnetic shield will protect the planet.

Auroral activity results from atomic particles spiralling into the earth's north and south polar atmosphere along magnetic field lines and then colliding with atmospheric molecules, resulting in the emission of energy in different forms including light.

Scientists have warned that a really big solar eruption could wreck satellites, power and communications grids.

Science writer Paul Sutherland, blogging on Skymania.com, says there have been two massive explosions on the Sun.

By chance, the explosions were aligned towards Earth, sending what Sutherland calls "a solar tsunami" toward Earth.

The solar outbursts on Sunday were recorded by several satellites including NASA's new Solar Dynamics Observatory which watched its shockwave rippling outwards.

UK solar expert Dr Lucie Green, of the Mullard Space Science Laboratory, in Surrey, followed the flare-ups using Japan's orbiting Hinode telescope.

"What wonderful fireworks the Sun has been producing," she told Skymania.

"This was a very rare event - not one, but two almost simultaneous eruptions from different locations on the sun were launched toward the Earth.

"These eruptions occur when immense magnetic structures in the solar atmosphere lose their stability and can no longer be held down by the sun's huge gravitational pull. Just like a coiled spring suddenly being released, they erupt into space.

Dr Green said if the eruptions do collide with the Earth's magnetic field the conditions need to be right for there to be an effect like the northern lights.