Science & Tech
Where is the solar max?
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Science & Tech
“Showtime!” Roger Woloshyn, a presenter at the Churchill Northern Studies Centre, in Churchill, Man., bellows as he walks down the hallway rapping on the bedroom doors of visitors who don’t immediately answer or snap to action.
Here, less than one kilometre from the icy shores of Hudson Bay, it is -35°C outside. But on this Friday evening in late March, the intrepid visitors who venture out onto the rock-solid northern tundra will be rewarded. Far beyond the Earth’s atmosphere, a fresh batch of charged particles recently burst from the surface of the sun, nearing the end of a 170,000-year journey that started at the sun’s core. The mass of matter and energy has radiated nearly 150 million kilometres through space on its way to triggering a light show over northern Canada. This evening’s aurora borealis above Churchill will be one to remember.
Twenty kilometres east of Churchill and on the edge of Wapusk National Park — Parks Canada’s denning sanctuary for nursing polar bears — the Churchill Northern Studies Centre has become a major stop in a growing aurora borealis tourism trade in Canada, along with Whitehorse and Yellowknife, where northern lights tour vans have been traded in for top-of-the-line buses.
Woloshyn has been coming to Churchill for more than 20 years to share the northern lights with eager “polar fleece stargazers.” By studying space weather predictions from days before, Woloshyn learned of the sun’s latest coronal mass ejection (a burst of solar wind and magnetic fields released into space), heading on a direct course for Earth. Tonight, he has studied satellitebased imagery of the auroral oval, part of which has been hanging over Churchill since before dinner. After going outside to visually confirm what he’s picked up from the satellite photos, Woloshyn excitedly makes the rounds and prepares to take his group outside for what could be the night of their lives.
For aurora tourists and space scientists alike, 2013 promises to be a stellar year. Solar activity — flares, sunspots, solar winds and other forms of radiation — is governed by changes in the sun’s magnetic field. These activities wax and wane on a fairly predictable 11-year cycle known as the solar maximum. The peak of this cycle hits this year (predicted to be September 2013 or later), which is why skywatchers and scientists are so excited. The solar maximum should bring with it the brightest and most frequent auroral displays for more than a decade. It will also give scientists the chance to examine aspects of space weather at its most violent and to measure its impact on the Earth infrastructure, such as electrical grids and communications.
Over the past 100 years, scientists have expanded our knowledge of auroras with insights into their origin in the sun and their interactions with the Earth’s atmosphere. Auroras are often associated with Earth-sized or larger sunspots (“holes” of magnetic disturbance on the sun), through which solar flares or huge looping flames called prominences erupt. If one of these “energy volcanoes” on a part of the sun is pointed toward Earth, the ejected material arrives on our doorstep in roughly half a week, about the time it takes an Amazon.ca shipment to travel between major cities.
When the eruption’s solar wind — plasma made up of ionized (positively or negatively charged) hydrogen atoms — hits the Earth, it’s travelling at hundreds of kilometres per second. Like iron filings being drawn to the poles of a bar magnet, the solar wind swirls into our planet’s magnetic fields near the North Pole and South Pole, setting in motion a sort of atmospheric dynamo. As these charged particles begin to move at hundreds of thousands of kilometres per hour, like great atomic tornadoes, they spin down along magnetic field lines into the Earth’s ionosphere (the region in which the International Space Station orbits). Eventually, they near the speed of light and become unstable, reacting directly with the planet’s magnetic field. At this point, the ionized atoms, up to now in an excited state, return to a non-excited state, creating so much heat in the process that they glow — green and sometimes red for oxygen and blue or pink for nitrogen.
On a global scale, this glowing takes the form of the auroral oval, a halo of light centred over the Earth’s geomagnetic poles. Earthbound observers watching this process see only a portion of the whole auroral oval when they’re treated to the dancing curtains of light known as the aurora borealis in the northern hemisphere and aurora australis south of the equator.
As luck would have it, Canada is the geographical hub of activity for auroral and space weather research. That’s because the Earth’s geomagnetic North Pole is shifted roughly 10 degrees down toward Hudson Bay from its geographical North Pole. “It’s not that we have just a slightly better view,” says University of Calgary space physicist Eric Donovan. “You have this oval that cuts across southern Greenland, Iceland and the very northern tip of Scandinavia, then skirts along the northern coast of Russia, comes down across Siberia and Alaska and cuts right across Canada. I would say 80 to 90 percent of the readily accessible land under the auroral oval is in Canada. We have a geographical situation where we can do things that others can’t.”
Beginning in the 1950s, Canadian researchers started to study the northern lights from the inside out by firing specialized “sounding rockets” into the aurora from Churchill and other locations. Half a century later, as a result of several generations of hard work and innovation, the Canadian North is populated with dozens of networked sensors that can capture data from below, confer with satellites high above and assemble a big-picture view of nearly the entire auroral oval, live, as it hangs over the northern hemisphere.
Since those early days of blasting rockets into the aurora, Canadian scientists have refined techniques that make use of radar, visual-light and multi-spectral cameras, Global Positioning System devices, magnetometers and other sensors, becoming world leaders in near-Earth space research. As the sun’s once-a-decade peak season kicks into high gear, those researchers will be ready with a network of space weather monitors larger and more powerful than any brought to bear during previous solar maximums.
For scientists such as Donovan, auroras are more than just pretty night skies. “What first hooked me on this research was the idea that I could use these visual images of the aurora to do plasma and magnetospheric physics,” he says. “I always loved the aurora but never connected it with what I was already researching. Then I looked at early images, where I could see things that were clearly unexplained and were related to the dynamics of the magnetospheric region of space around the Earth. So I was just captivated by the beauty of it and the possibility that I could link this beautiful thing to the things I have been trying to study.”
Donovan is the team leader and principal investigator for more space weather observation projects than anyone else in Canada. He oversees a growing network of nearly 60 instruments that study the aurora in northern Canada — the largest such effort on Earth. From his University of Calgary lab, which is more of a repair shop for an endless parade of different sensors and detectors, to his “lab” that spans several million square kilometres of the Canadian Arctic and subarctic, Donovan and team are ready to capitalize on the storm season in space.
“We have buildings and sheds and huts and aluminum tubing and cameras in places ranging from Happy Valley- Goose Bay in Labrador, to Rankin Inlet in Nunavut, to Inuvik, in the Northwest Territories,” he says. The latest addition is a $25 million installation curently being built in Resolute Bay, Nunavut, known as the Resolute Incoherent Scatter Radar-Canada (RISR-C). When completed, RISR-C will be an arena-sized array of sensors used for studying the properties of the Earth’s upper atmosphere. Donovan and his team also have colleagues running cameras for them in the Faroe Islands, Iceland and other locations, and are quickly forging new relationships from Greenland to China.
“What we’re doing now is system-level geospace science,” says Donovan of the approaching 11-year peak of solar activity. “That science is really high-level solar-maximum science.” Many questions about the Earth’s atmosphere remain unanswered, including: What affects the Earth’s radiation belts? What affects the upper atmosphere? What affects the Earth’s atmospheric composition? How does near-Earth’s atmosphere control what’s going on in the Earth’s space? How does the Earth’s atmosphere supply plasma to the near-Earth space? “To answer these,” he says, “you have to go from deep quiet to big active times to deep quiet again, not in years, but in days or weeks.”
As part of his team’s study of the near-Earth space environment, Donovan oversees Canadian ground operations of NASA’s THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission. Combining forces with a group of Earth-orbiting satellites in 2008, THEMIS researchers found that Earth is connected to “weather” from the sun via a series of magnetic “ropes.” Rather than causing changes in the Earth’s magnetic field directly, this dynamo process fires-up the aurora when highly conducting plasma from the sun revs up a natural particle accelerator in our atmosphere and converts magnetic energy into kinetic energy.
While scientists are learning more about how space weather fires up the aurora, they are also focusing attention on how space weather can short-circuit the Earth’s electrical and communications networks. The stakes can be high. In 1859, a violent coronal mass ejection travelled to Earth not in days but in mere hours, interacting so fiercely with the Earth’s magnetosphere that it knocked out telegraph systems all over the planet. The Carrington Event — named for the scientist who discovered the flare just before it hit — caused planet-wide auroral displays visible all the way to the Caribbean. Gold miners in the Rocky Mountains were awoken by the display, thinking it was morning. Less severe storms in 1921 and 1960 took out much of the Earth’s radio transmission capability, disturbing the airwaves with a smog of ionizing radiation. A 1989 event brought down a good portion of Hydro-Québec’s power grid, causing millions of dollars in damage and prompting a $1.2 billion transmission-line upgrade.
But that’s nothing compared with what a severe solar storm could do in 2013, when almost every aspect of our daily lives depends on electronics that could be incapacitated by a sufficiently vigorous solar eruption. If the Carrington Event were to happen today, it could scramble the radio waves used for everything from Global Positioning Systems to TV to mobile devices (all of them) and damage or destroy the satellites that carry radio and television programming, telephone calls, texts and directions to and from those devices. In other words, even after we had transmission capability back, we might not have any satellites left to transmit them through. This past year, the U.S. National Academy of Sciences estimated that for the United States alone, the socioeconomic impact after a severe solar storm could top $2 trillion in the first year of recovery.
“The space storms that produce these beautiful light shows can potentially have serious, damaging consequences if we’re unprepared for them,” says Ian Mann, who holds a Canada Research Chair in Space Physics at the University of Alberta. He says that projects such as THEMIS are critical to piecing together the puzzle of how space weather affects life on Earth. “As part of THEMIS, we have cameras taking pictures every three seconds across nearly the whole band of the auroral zone, so for the first time, we have threesecond- cadence capability of imaging a huge swath of the auroral zone and its dynamics under various magnetic conditions. We’ve never been able to see that kind of structure before. While satellites give an overall picture of the auroral oval, their resolution is nothing like what you can see when you add information from ground-based sensors.”
Mann currently serves as principal investigator for CARISMA (the Canadian Array for Realtime Investigations of Magnetic Activity), which measures disturbances in the Earth’s magnetic field though a network of 28 magnetometers ranging from Dawson, Y.T., to Ann Arbor, Michigan.
Because these devices are distributed across western North America and not just under the auroral oval, Mann can see how space weather events radiate south all the way down into the northern United States, where researchers can record measurements that help build models of how such events could affect large numbers of people in highly populated areas.
With the installation of additional sensors, Mann says that scientists can more accurately understand the processes that accelerate particles in near-Earth space to almost the speed of light. “It’s like trying to piece together what conditions cause a hurricane,” he says. “The more weather stations you have, the more you can see and make predictions about what conditions drive it, what structures cause it and how it evolves.”
The next step in such research, says Mann, is to be able to predict space weather and its potential damaging impacts with enough speed and accuracy to serve as a useful early warning system, similar to meteorologists on Earth looking at largescale systems to predict whether there’s going to be snow, thundershowers or even a hurricane the next day.
Back in Churchill, the evening’s light show is in full swing. As the aurora performs its striking dance, all heads are turned skyward. Over the course of half an hour, the northern lights blaze brighter than the full moon. The brilliant fluttering curtains look like a hologram of a citysized piece of corrugated cardboard blowing in the wind. Some visitors in the group whoop for joy; some stand in awed silence; a few break down in tears. Although he has seen the spectacle a great many times, aurora guide Roger Woloshyn is still moved. Looking up, he says, “I feel as if I’m in a cathedral of light.”
Then, as quickly as they flared up, the lights die down and vanish. “Can we see them again?” asks one optimistic onlooker. Woloshyn can only smile and explain the laws of the universe. For this grand spectacle of nature, he says, there’s no instant-replay button.
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