Earth in the hands of an Angry Sun
Pastor Dale Morgan
The Sunday Times September 18, 2006
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Earth in the hands of an Angry Sun *
Jonathan Leake, Science Editor
Satellites to give early warning of solar explosions that cause
electrical chaos
HUMANITY is about to get its first early-warning system against solar
flares, the massive explosions that periodically erupt from an angry
sun, with the launch of three satellites to study the phenomenon.
Such flares — also known as coronal mass ejections — can release as much
energy as a billion megatons of TNT or 300,000 power stations.
They are so powerful that they can wipe out communication satellites,
disrupt aviation, bring down power grids and, potentially, kill astronauts.
However, despite the disruption they can cause, scientists have until
now found them impossible to predict.
This week a consortium of the world’s space research agencies is due to
launch Solar B, the first of three satellites designed to study such
flares — and create the first early-warning system against them. Next
month two more probes, the so-called Stereo mission, should follow Solar
B into space.
“Currently, solar flares can cause huge damage with very little
warning,” said Chris Davis of Britain’s Rutherford Appleton Laboratory,
which is involved with both projects. “With these satellites we might
predict them days beforehand and be prepared.”
Solar B, built by teams from Britain, America and Japan, is due to be
launched on September 22 from the Uchinoura space centre in southern
Japan. Its three instruments will try to find out what happens on the
sun’s surface just before solar flares erupt. One of them, a telescope
built by a team from University College London (UCL), will watch the
sun’s atmosphere for signs suggesting the surface is building up to an
explosion.
“Solar flares are fast and furious and can cause communication blackouts
on Earth within 30 minutes of erupting from the sun’s surface,” said
Professor Louise Harra, the UK Solar B project scientist based at UCL’s
Mullard Space Science Laboratory. “It is imperative that we understand
what triggers these events.”
The two Stereo probes, built and launched by Nasa, the American space
agency, but also carrying British instruments, will have the
complementary task of observing what happens to solar flares once they
erupt into space.
If a flare appears to be heading for Earth, the probes will trigger
alerts so satellites can be prepared for the blast.
The Stereo satellites will be launched together in a single rocket, but
once in space they will move apart. Chris Eyles of Birmingham
University, said: “One spacecraft will move ahead of the Earth, the
other lag behind. The resulting offset will allow the two spacecraft to
have stereo vision such as humans have.”
It also means the spacecraft will be able to generate high-quality
three-dimensional “movies” of solar flares. If these are good enough
they could be turned into Imax-style films and put on general release.
Solar flares are generated by the bizarre way in which the sun rotates,
with its equator spinning every 25 days — while the poles take five days
longer. This difference in speed slowly twists the sun’s powerful
magnetic fields into giant knots. As these distortions build up, the
magnetic forces become concentrated in certain parts of the sun’s
surface, bottling up its red-hot plasma and radiation and so creating
cooler areas known as sun spots.
Eventually, the repressed energy bursts out, resulting in an explosion
of radiation, high-energy particles and associated magnetic fields that
hurtle into space at millions of miles an hour.
Earth’s magnetic fields protect humanity from the direct effects of such
storms, but growing dependence on satellites for communication and
navigation means that a massive solar flare could spell disaster.
The collapse of satellite links could lead to a meltdown in stock
markets and endanger aircraft and ships that depend on global
positioning systems.
One of the most powerful solar flares on record happened in September
1859, when the sun doubled its brightness for some minutes. The surge in
magnetism induced powerful electrical currents in telegraph wires across
Europe, igniting widespread fires.
That event was three times more powerful than the strongest solar flare,
or space storm, in modern memory, which occurred in 1989, but even that
was able to burn out power cables and black out Quebec.
The Apollo moon programme narrowly escaped disaster in 1972 when a solar
flare erupted just as one crew had returned from the moon and another
was preparing for launch.
If it had happened during a mission the astronauts would have received a
potentially fatal dose of radiation.
Professor Keith Mason, chief executive of Britain’s Particle Physics and
Astronomy Research Council, said: “Predicting the timing and strength of
solar eruptions is becoming vital and these observatories will be
Earth’s new sentinels.”