Contact: Dr. Roger Clay
Adelaide University

Australia’s new national power grid and hundreds of satellites orbiting
the Earth may have survived a recent solar particle explosion, but they
might not be so lucky next time.

The warning comes from Adelaide University physicist Dr Roger Clay in
the wake of last month’s solar storm which hit Earth with an
interplanetary shock wave of ionized gas and magnetic fields.

Dr Clay said the solar storm on 18 February — technically known as a
coronal mass ejection (CME) of high-energy particles — did not cause as
much damage as some had feared, but it was likely to be the first of
such explosions in the next two to three years.

A CME consists of a group of atoms, known as a plasma, which have had
their electrons stripped away from the nuclei. These travel towards
earth at speeds up to 500km per second.

In sufficient quantities, the wave of particles can disrupt satellites
in their path and even create an electric current big enough to disturb
the Earth’s magnetic field, overloading electric power systems.

Dr Clay said the Sun had just begun its most active phase — known as
“solar maximum” — with the February CME likely to be the first of many
such explosions.

He said the last phase 11 years ago had caused a major disruption to the
Canadian power system. Since then, many more satellites had been put
into orbit around the Earth, many of which were not “radiation

“If the next solar storm is no worse than the one last month, then
there’s no problem,” he said.

“But of course, since the last solar maximum 11 years ago, we’ve got a
lot more satellites and we depend a lot more on satellites.

“All our communication satellites, our GPS systems and these sort of
satellite systems have computer chips in them.” says Dr Clay.

“The computer chips are susceptible to these particles going through
them because they deposit electrons in there, and that’s enough to
change a zero to a one in the computer memory, which could effectively
disable the satellite.”

Dr Clay said the solar discharge also posed a threat to the Earth
because it was equivalent to a huge electric current passing by us.

“That huge external current can disturb the Earth’s magnetic field and
induce very large currents here on Earth.” said Dr Clay.

“If you’ve got a large loop of wire, and you’ve got a magnetic field
through it, a change in the magnetic field induces an electrical
current through the wire.

“There is a move to integrate power grids across countries so, as in
countries, what we have here in Australia, as we’ve been joining up
between the states, are huge loops of line all connected together. When
Earth’s magnetic field changes quite rapidly, it can induce big currents
in the national grid, and those currents may overload the system. This
what happened in Canada.”

Dr Clay said CMEs would also cause major dangers for humans in space,
who are without the protection of Earth’s atmosphere.

“The Apollo astronauts have said that when they shut their eyes they saw
‘flashes’. Those flashes were due to these particles going through
their eyes,” Dr Clay said.

“It’s a high-radiation environment, and it can kill. It’s like
continuous radiotherapy. We don’t have an effective protection against
it, outside of the Earth’s protective atmosphere.

“Right now space agencies building a new space station to orbit the
Roughly one person in one hundred per year in such an environment would
from this radiation,” he said.

Dr Clay said Adelaide University’s Department of Physics and
Mathematical Physics has been operating two radiation detectors — one
for about two years, and another commissioned earlier this year — to
study solar effects.

The 18 February CME was the first substantial test for the older
detector, which responds to the early effects of CMEs, with the
department now hoping to develop this detector into an automated solar
storm predictor.

The newer detector recorded the local arrival of the solar debris at the
Earth some four days later.


*Photo available at

Contact: Dr Roger Clay (618) 8303 5046 (618) 8303 5996

Dr Rob Morrison
Science Journalist
Media, Marketing & Publications Unit
Adelaide University
work: (618) 8303 3490
fax/w: (618) 8303 4838