The volcano hurling ash 12 miles high

National Geographic

It may not have done anything for 9000 years, but now Chile’s Chaitén volcano has decided to start erupting it’s doing it big-time. Blowing ash 12 miles up into the sky, it has caused stunning ‘dirty storms’ where the huge dust clouds have turned into ferocious lightning storms. The photos are pretty breathtaking – although I must say I’m glad I don’t live anywhere what seems like a volcano taken out of the apocalypse.

National Geographic It looks stunning, but just how do you get so much lightning at once? Basically, as the billions of ash and dust particles rub together in the sky, static electricity causes some of them to become charged – just like rubbing a balloon on your jumper can make it become statically charged.

These charged ash and dust particles can then trigger huge bolts of lightning, some reaching down to the ground and some staying between the clouds. The result: a dazzling show of light – and of course sound as well.

Map image

Chaitén’s not just making dirty storms – its ash clouds are spreading right over as far as the Atlantic Ocean, and it’s spewing lava out too (although not at a very high rate yet). It’s definitely something to keep an eye on over the next few days.

National Geographic’s done a great interactive detailing everything you could ever want to know about volcanoes – click here.

Planet Earth plunges into darkness for an hour

MSNBC

Whoa! What happened to Sydney in the photo above? Was there a major power outage or something?

Fortunately no – although what actually happened was something even more important than a power outage. At 8PM local time on March 29, Sydney was one of the first cities to participate in ‘Earth Hour’, in which households, towns and even major cities around the world turned off their lights for an hour to try to help save our planet. And as you can see from the photos, the effect was quite impressive.

NASA Earth Hour started last year as a Sydney-only event, but this year it’s spread to the whole world thanks to WWF funding. By the time you read this, chances are that it will be past 8PM in the U.S., where buildings from the CNN Center in Atlanta to the Golden Gate Bridge in San Francisco will be thrown into darkness.

It’s all very well doing publicity stunts like Earth Hour, but do they really make a difference? Skeptics would say they’re just a gimmick – people are more bothered about the excitement of a candlelit dinner than about the real message of Earth Hour.

NASA But I really do think it will make people think. In some cities office workers were forced to turn their lights off on Friday evening so that they didn’t have to go in again on Saturday – maybe next week they’ll remember to do it again. And of course any publicity about saving the environment is always a good thing.

Oh yeah, and there’s one other huge advantage of having lights out for an hour – as you can see from the Sydney photo, the normally orange, light-polluted sky turned black during Earth Hour, making it one of the only times Sydney residents can ever see the stars above their heads.

Let’s just hope that Earth Hour can become an annual tradition all around the world. Put March 29 in your 2009 diary!

Mega-tsunami imminent in the Mediterranean – 100 years and counting

The 2004 Indian Ocean tsunami, which killed over 200,000 people | Image: Wikipedia It’s not every day that you have the same experience as the people who lived on the Mediterranean island of Crete in AD 365: All of a sudden, the ground below them rose a massive 30 feet (10 meters) in a burst of tectonic activity. Even with all our knowledge how the planet works, I’d still be pretty confused if that happened to me tomorrow.

But the huge uplift wasn’t all that happened: a massive tsunami was unleashed that went on to kill tens of thousands of people across the region, as well as destroying the ancient Egyptian city of Alexandria. It ravaged huge areas from Greece down to Libya, and managed to carry ships up to two miles inland.

Map of the Mediterranean island of Crete

Scary? It almost sounds like a Greek myth. But the worrying thing is that new research suggests that a similar tsunami occurs every 800 years – after the 365 tsunami, another one took place in around 1300, meaning that the Mediterranean is due for another wave of destruction anytime in the next century.

Millions of people live around the area that would be affected, meaning that if a tsunami was to strike it would cause unimaginable devastation. It could well be worse than the tragic 2004 south-east Asian tsunami that killed over 200,000 people.

But wait a minute… how can scientists tell that Crete rose 30 feet in AD 365, and that another tsunami is due soon? They know about Crete because there is a line of animal and plant remains running along Crete at a height of around 30 feet, like the line in a bath where water has been up to. And they know another tsunami is imminent because they have carefully analyzed the miniscule movements of the tectonic plates over recent years, as well as looking back at records of the 365 tsunami.

Should we be worried, or is this just a scare story? Some scientists argue that the 365 tsunami was just a one-off event… I’m personally more convinced by the 800 year cycle story – you’ll have to decide for yourself.

Related: Did you know that Italy is currently on a collision course with Croatia – click here