Scientists solve northern lights mystery

An international team has discovered that when Earth's "magnetotail" snaps out in space, the northern lights start dancing across Canada's skies.

One explosive release in February - which occurred about 127,000 kilometres away, or a third of the way to the moon - sent enormous amounts of energy hurdling towards Earth. A minute-and-a-half later a spectacular aurora display lit up the skies, say the scientists, whose work with five NASA satellites and 20 ground stations across Canada and Alaska is revolutionizing our understanding of space weather.

"We discovered what makes the northern lights dance," lead investigator Vassilis Angelopoulos of the University of California, Los Angeles said in announcing the discovery Thursday.

The Aurora Borealis or Northern Lights dance across a starry night sky at the Yellowknife Boat Launch on Great Slave Lake.

Scientists have been trying to figure out for decades what makes the aurora swirl and undulate through the northern and southern skies.

The $200-million system of satellites and ground stations has, in effect, allowed them to "fly into the eye of the storm," says space physicist Ian Mann from the University of Alberta, a member of the team that has published its new findings online in the journal Science.

They say explosive short-circuits, or reconnections, in Earth's magnetic field lines trigger the onset of so-called "substorms" which cause the aurora to suddenly brighten and dance.

Earth's magnetic field, which protects the planet from harsh solar radiation, absorbs energy from the solar wind, which is constantly buffeting the planet. The wind stretches Earth's magnetic field lines far off into space producing the magnetotail, says NASA scientist David Sibeck. But he says the magnetic field lines can only be stretched so far before they snap "like rubber bands."

"You build up these big currents, you store lots of energy and then suddenly BANG, they snap," Sibeck told a media teleconference. Vast amounts of energy are then flung back toward Earth, powering up the aurora in both the northern and southern hemispheres.

Such "substorms" typically occur several times a day. They vary greatly in intensity, with some dumping so much energy into Earth's atmosphere that they can damage satellites, endanger astronauts and disrupt power lines and communications on the ground, say the scientists, who hope their work will lead to better space weather forecasts.

To try find out what causes the spectacular light shows, NASA and its partners launched a flotilla of five identical satellites, the size of washing machines, in February 2007. The satellites line up on the same side of the Earth once every four days and can pinpoint where and when substorms begin. They can also track the corresponding disturbances "spreading like wildfires in space," says Sibeck.

The satellites are coupled with 20 ground stations, which have magnetometers and sophisticated cameras pointing skyward. They measure the currents and aurora swirling through the heavens during substorms.  

"We're talking about million-amp currents pumped into Earth's atmosphere," says Sibeck. The cameras snap pictures every three seconds, enabling the scientists to follow aurora shows across the continent from Alaska to Newfoundland.

The system was perfectly aligned to catch the Feb. 26 substorm. One satellite was on the far side of the magnetic field lines that snapped, or reconnected, 127,000 kilometres from Earth. The other four were closer to Earth and measured the resulting power surge as it raced back toward the planet. The ground stations caught the aurora lighting up about 1.5 minutes after the initial explosion, says Angelopoulos.

"It's a quite a beautiful sequence of cause and effect," says Mann.

"We can pinpoint where the action was right at the beginning of the boom, and then we can see the effect twang down toward the planet and release energy in the form of the northern lights over Canada and Alaska."

It's "pretty wild" to think reconnecting magnetic field lines more than 100,000 kilometres away can get the aurora dancing overhead, says Eric Donovan of the University of Calgary, who heads the Canadian component of the project.

He says the finding is just "a taste of what's to come" from the mission, which is revolutionizing understanding of the aurora.

"It is going to change the field of space physics forever," says Donovan, noting there are all kinds of strange and mysterious features in the northern lights. "What we don't know outnumbers what we do know."

http://www.canada.com/topics/technology/story.html?id=9ed5d2ac-c4f5-4299-b92d-2ed4e793743c

Its taken NASA this long to find this out? No wonder a manned flight to mars is so far away

Perhaps now they can invest all of that time and money into something useful.

The ignorance of some posters astounds me.

You can't just throw money at a mission to mars and go there. It's much more complicated. Learn to appreciate the hard work NASA does and be grateful the US has an agency like NASA, most countries don't.

Probably because most countries would rather spend money on other, useful, projects.

NASA is not useful? Do you even know what NASA does. NASA is not just a Space Agency. Do you even know what NASA stands for?

The work NASA is doing now is vital because when our resources run out, we'll need somewhere else to find them, likewise we will need to vacate off of this planet if we want to survive. Don't give me that useless bullshit, a lot of people have died doing 'useless' things according to you then. Show a bit of respect.

If everyone was like you we'd be in the stoneage, for why should we bother pursing useless knowledge?

So, wait, you expect NASA to find oil on the moon? If you do think that, you better learn how oil was made.

Google tells me that NASA stands for National Aeronautics and Space Administration, which means it covers pretty much what I expected it to cover.

Did I say oil? No. Oil is not the ONLY resource in the whole world. Every heard of He3, Gold, Silver, etc?

Notice the Aeronautics part. I'll simplify it for you. It means things aircraft in the sky. You need to study ALL aspects of what is in the sky in order to fully understand it and therefore make your aeroplanes/shuttles able to resist certain events.

What is wrong in spending money on solving something like that?

Ok, let's all scrap the space agencies and sit here continuing with 'important projects' for the next 600 million years until this planet becomes uninhabitable due to heat. Let's also hope nothing like a comet or asteroid hits us, because that means we have to use science and that's a bad thing because it is money that could be spent on more useful projects.

Please do not talk on a subject of which you have no knowledge. If you come out with a half arsed reply showing no understanding I will simply ignore it.

rofl at this thread.

Someone post some pictures of the Northern Lights, quick...and calm these guys down. This should be a beautiful thread.

ohhhwww pretty!!

and cool!