Europe launched its first space weather coordination centre Wednesday to raise the alarm for possible satellite-sizzling solar storms that also threaten astronauts in orbit, plane passengers and electricity grids on Earth.
Though impossible to predict, a worst-case scenario mega-storm can happen at any time, leaving the world without Internet, telephones, television, electricity and air and rail transport for days on end.
Limited precautions can be taken, but early warning is key, say experts at the European Space Agency (ESA) which runs the centre from Brussels.
"A pilot can always land a plane... because they have alternatives (to satellites) for navigation, but if they get the disturbance without warning, at the wrong time, that can be dangerous," Juha-Pekka Luntama, head of ESA's space weather division told AFP at the launch.
Even a slight satellite glitch can put navigation out by 100 metres (yards)—enough to miss a runway.
Earth's atmosphere and magnetosphere protect the planet from radiation released during solar flares and geomagnetic storms—some of the most severe forms of space weather.
Smaller eruptions usually have little noticeable effect—perhaps slight problems with car navigation systems or mobile phones.
But a major solar storm on the scale of an event in 1859 that crippled global telegraph systems could have severe impacts today.
A "coronal mass ejection"—which sends electromagnetic radiation flying towards Earth at a speed of some 2,500 kilometres (1,500 miles) per second and plays havoc with long transmission lines— caused surges on telegraph lines so strong in 1859 that offices caught fire and operators received electric shocks.
Such super storms happen "only very occasionally, perhaps once or twice a century," according to ESA's human spaceflight director Thomas Reiter.
Luntama added that the most severe storms statistically happen around the solar maximum—a period of greatest activity in the 11-year solar cycle—where we are now.
"In some ways you can say that the next two years is the time period that a solar event is more likely," he said.
An 1859-like storm today could claim about 50 to 100 satellites—10 percent of the total in orbit, at a cost of billions of euros, according to ESA.
But probably the biggest threat to Earth lies in electric power grid surges.
"In the worst case, what could happen is that the transformers in the power grid are damaged and in that case, replacement of the transformers can take weeks or months," said Luntama.
Even if only a small part of the grid is damaged, overloading in neighbouring systems can lead to more blackouts that spread domino-like, such as the nine-hour power blackout in Quebec in Canada in 1989.
Astronauts orbiting Earth on the International Space Station (ISS), closer to the source of the radiation, could be at high risk of a severe solar storm, as could plane crews and passengers flying over the polar regions.
Precautions would include turning off satellites to lessen the risk, reducing the load on power grids, astronauts taking cover in well-shielded part of the ISS, and planes being diverted or even grounded if communications become unreliable.
Once witnessed by space weather watchers, the fallout from a solar storm takes between 17 and 48 hours to reach Earth, depending on its severity.
The coordination centre, a central point for space weather enquiries, will draw on the expertise of dozens of European universities, research institutions and private companies.
A similar service already exists in the United States.
For the moment, the ESA service—funded by 14 member states— is free.
The centre started operating six months ago and is expected to be fully operational by 2020—part of wider, multi-billion euro ESA system that also tracks objects in space that pose a collision threat.
What is space weather?
Space weather is caused mainly by storms and eruptions in our volatile Sun sending potentially dangerous radiation towards Earth.
It also causes the spectacular "aurora" light displays that have awed so many in the polar regions—a beautiful show of radiation hitting Earth's magnetic field.
The Sun randomly and suddenly ejects bursts of its component plasma or magnetic matter in events called coronal mass ejections (CMEs), and is subject to equally arbitrary bursts of radiation called solar flares.
The life-giving star at the centre of our solar system emits radiation at temperatures of millions of degrees and constantly ejects charged particles and radiation that travels through space on solar wind.
Sudden flares or outbursts can cause geomagnetic storms that affect Manmade systems in space and on Earth, though the magnetosphere protects us humans from the worst effects on the ground.
CMEs, for example, can trigger magnetic current surges on long terrestrial lines like electric power lines.
The magnetic disturbances can also throw out radar and radio signals.
Out alone in space, satellites are easy targets.
Solar flares boost the level of radiation that reaches Earth and its atmosphere, which expands and becomes more dense for satellites to move through, causing drag that reduces their lifetime.
Satellites can also fall victim to sudden magnetic charge changes damaging their electronics.
There is a small risk for humans.
Some research says aircrew flying frequently at high altitude on long-haul flights may receive a radiation dose equivalent to several chest x-rays from exposure to solar flare radiation.
Astronauts, too may be in danger, hence extra-protective shields against radiation bursts that are provided in parts of the orbiting International Space Station.
Space weather is monitored by looking at the Sun with satellites and telescopes and measuring changes in the Earth's magnetic field and radio noise.
Even the aurora are monitored—changes in their shape can indicate solar storm events.
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