After Sun's 'Solar Tsunami'

(News Today) - Skywatchers in the UK will get a second chance to witness the Northern Lights tonight after missing out on the spectacular sight last night.

Parts of northern America, in particular the state of Michigan, were lucky enough to be given clear skies last night and managed to catch the incredible display.

And David Gavine, the director of the British Astronomical Association's Aurora division, said that there is every chance the UK might be able to see similar views tonight.

'I am looking into reports that Denmark saw aurora last night, which is exciting because they are on the same latitude as Scotland,' he said.

'So there's every chance, if the skies are clear that we might see something tonight.'

Even though northern states like Michigan are far further south than the UK they are still more likely to see the Northern Lights. This is because the aurora appears along Earth's geomagnetic latitude rather than geographic latitude.

Earth's geomagnetic Pole is based in northern Canada rather than the North Pole meaning the viewable zone for aurora is tilted so that northern states in the US are much more likely than the UK to see a display.

The prospect of seeing the aurora borealis from the UK is because two minor solar storms that flared on Sunday are shooting tons of plasma directly at Earth. Usually only regions closer to the Arctic can see the aurora of rippling reds and greens, but solar storms pull them south.

Early on Sunday morning, the Sun's surface erupted and blasted tons of plasma - ionised atoms - into interplanetary space.

'This eruption is directed right at us, and is expected to get here early in the day on August 4th,' said astronomer Leon Golub of the Harvard-Smithsonian Center for Astrophysics (CfA). 'It's the first major Earth-directed eruption in quite some time.'

The eruption, called a coronal mass ejection, was caught on camera by NASA's Solar Dynamics Observatory (SDO) - a spacecraft that launched in February. SDO provides better-than-HD quality views of the Sun at a variety of wavelengths.

'We got a beautiful view of this eruption,' said Golub. 'And there might be more beautiful views to come, if it triggers aurorae.'

When a coronal mass ejection reaches Earth, it interacts with our planet's magnetic field, potentially creating a geomagnetic storm. Solar particles stream down the field lines toward Earth's poles.

Those particles collide with atoms of nitrogen and oxygen in the atmosphere, which then glow like miniature neon signs. Aurorae normally are visible only at high latitudes. However, during a geomagnetic storm aurorae can light up the sky at lower latitudes.

Sky watchers should look toward the north this evening and tomorrow evening for rippling curtains of green and red light. The Sun goes through a regular activity cycle about 11 years long on average. The last solar maximum occurred in 2001. Its latest minimum was particularly weak and long lasting.

This eruption is one of the first signs that the Sun is waking up and heading toward another maximum. The storms are not expected to be much of a threat to satellites or power grids.

Source : kompas

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