How to predict and prepare for space weather
Autor: Francisco Alexandre da Costa | Publicado: 2017-02-28T17:57:00-03:00






SOMETIMES the sun
 burps. It flings off mighty arcs of hot plasma known as coronal mass 
ejections (CMEs). If one of these hits Earth it plays havoc with the 
planet’s magnetic field. Such storms are among the most spectacular 
examples of what astronomers call space weather, a subject to which a 
session at this year’s meeting of the American Association for the 
Advancement of Science (AAAS), in Boston, was devoted. A big CME can 
have profound effects. In 1859, for instance, a CME subsequently dubbed 
the Carrington event, after a British astronomer who realised its 
connection with a powerful solar flare he had observed a few days 
earlier, generated auroras that could be seen in the tropics. Normally, 
as the names “northern” and “southern” lights suggest, such auroras 
(pictured above) are visible only from high latitude. More significant, 
the Carrington event played havoc with Earth’s new telecommunications 
system, the electric telegraph. Lines and networks failed, and some 
operators received severe shocks.

Today, the damage would be 
worse. A study published in 2013 by Lloyd’s, a London insurance market, 
estimated that a Carrington-like event now would cause damage costing 
between $600bn and $2.6trn in America alone. A year before this report 
came out the sun had indeed thrown off such an ejection—though not in 
the direction of Earth. A much smaller storm did, however, do serious 
damage in 1989, by inducing powerful currents in Quebec’s grid, blacking
 out millions of people. It would therefore be useful, Jonathan Pellish 
of the Goddard Space Flight Centre, a NASA laboratory, told the meeting,
 to be able to forecast space weather in much the same way as weather is
 forecast on Earth. This would permit the most vulnerable equipment to 
be disconnected, in advance of a CME’s arrival, to prevent damaging 
power surges.

Sturm und drang

It sounds 
straightforward enough, but is harder than it sounds. Though CMEs are 
common, they cause problems on Earth only if they score a direct hit. 
The so-called “empty” interplanetary space of the solar system is, in 
fact, suffused by a thin soup of charged particles. These particles 
interact with moving CMEs in ways that are hard to predict. That makes 
forecasting a storm’s track difficult. On top of this, CMEs themselves 
have magnetic fields, with north and south poles, just as Earth does. 
The way the poles of a CME line up with those of Earth can affect the 
intensity of the resulting electrical activity.

To try to 
understand all this better a number of satellites already monitor the 
sun, looking for, among other things, CMEs. These include a fleet of 
American environment-modelling craft and also the Solar and Heliospheric
 Observatory, which is a joint European-American venture launched in 
1995. Several new sun-watching instruments are planned for the next 
couple of years. One is the European Space Agency’s Solar Orbiter. 
Another is NASA’s Solar Probe Plus. A third is a special telescope, 
called DKIST, to be built in Hawaii. The eventual goal, said Dr Pellish,
 is to make space-weather forecasts as easy and routine as terrestrial 
ones.

Preparing for the extraterrestrial equivalent of hurricanes 
in this way is surely wise. But space drizzle can cause problems too. 
Even when the sun is quiet, Earth is bombarded by a steady stream of 
high-energy subatomic particles. Some come from the sun, which is always
 shedding matter in small quantities even when it is not throwing off 
CMEs. Others are cosmic rays, which originate from outside the solar 
system. Both types, when they smash through the atmosphere, create 
showers of secondary particles in their wake. And, as Bharat Bhuva, an 
engineer at Vanderbilt University in Tennessee, described to the 
meeting, this shrapnel can cause problems with the electronic devices on
 which people increasingly depend.

If such a particle hits a 
computer chip, it can inject an electrical charge into the circuit. 
Since chips work their magic by manipulating packets of charge, that can
 create all sorts of problems. Dr Bhuva described how, in 2008, the 
autopilot of a Qantas airliner had been knocked out by a rogue particle.
 The resulting sudden plunge of about 200 metres injured many of the 
passengers, a dozen seriously.

Subtler effects can be just as 
worrying. During a local election in Belgium in 2003, a single scrambled
 bit of information, almost certainly caused by an errant particle, 
added 4,096 votes to one candidate’s tally. Since this gave an 
impossibly high total, the mistake was easily spotted. But had the 
particle hit a different part of the circuit it might have added a 
smaller number of votes—enough to change the outcome without anyone 
noticing. Moreover, as the components from which computer chips are 
built continue to shrink, they become more sensitive, making the problem
 worse. A modern computer might expect somewhere between a hundred and a
 thousand space-drizzle-induced errors per billion transistors per 
billion hours of operation. That sounds low. But modern chips have tens 
of billions of transistors, and modern data centres have millions of 
chips—so the numbers quickly add up.

The trick is to design 
circuits to cope. That is where Christopher Frost, who works at the 
Rutherford Appleton Laboratory, near Oxford, thinks he can help. He and 
his team have modified some particle accelerators in a way that offers 
designers of electronic equipment the ability to test their 
products—and, crucially, to test them quickly. Dr Frost’s particle beams
 are millions of times more intense than the radiation experienced by 
real-world devices. They deliver in minutes a dose that would take years
 to arrive naturally.

This sort of pre-emptive action makes sense.
 The threats from space drizzle (constant, though low-level) and from 
CMEs (rare, but potentially catastrophic) are real. Hardening equipment 
against drizzle, and developing forecasts that tell you when to 
disconnect it to avoid CME-induced power surges, are merely sensible 
precautions.



This article appeared in the Science and technology section of the print edition under the headline "Tales of wonder"&nbsp;Source: The Economist&nbsp;