Since Tuesday 28 October, explosive events originating from the Sun have
been bathing the Earth and its surroundings in high energy radiation.
Although 150 million kilometers away, the Sun is still capable of causing
major disruption here on Earth to a range of systems that we depend on in
everyday life. These include communication and navigation systems,
aircraft and spacecraft operations and the distribution of electricity at
high latitudes.

The activity started on Tuesday with a giant solar flare — the second
biggest ever seen by SOHO, the ESA-NASA solar observatory that maintains a
constant watch on the Sun, monitoring these events as they happen. A few
minutes later, spacecraft circling the Earth began to detect high levels
of energetic radiation, capable of blinding satellites and causing
increased radiation levels down to normal aircraft cruising altitudes.
About 24 hours after the solar flare was observed, an accompanying coronal
mass ejection — a giant cloud of magnetised plasma — reached the Earth,
causing rapid changes in the Earth’s magnetic field and what is known as a
geomagnetic storm. This storm caused widespread disruption to
communications; both satellite-based and HF radio.

These events are truly sporadic and extremely difficult to predict. On
Wednesday it appeared that radiation levels were decreasing. However, a
second flare overnight has caused a further sharp increase in radiation
levels. Here on Earth, the disruption continues today with a further
coronal mass ejection expected to reach the Earth tomorrow in time for

Solar eruptions of this type together with the associated increased
radiation levels and electromagnetic disturbances around the Earth have
real immediate and long-term economic impacts. During the last few days,
space weather related problems have been detected on spacecraft operated
by a range of agencies across the globe and operations teams are on alert.
On Earth, telecommunication links have been disrupted and steps have been
taken to safeguard aircraft, which including some changes in scheduling.
Effects have also been detected in high latitude power grids and are being
carefully monitored.

The increased dependency of our society on systems which are directly
or indirectly influenced by solar and other events seen in space raises
concerns about our ability to monitor and anticipate these events and the
resulting changes collectively referred to as space weather. At the
European Space Agency these issues are being handled jointly in the
Electromagnetics and Space Environment Division by Dr Eamonn Daly’s
group for the specifications of spacecraft protection and in the
spacecraft operations teams.

In addition, Europe-wide coordination is currently being set up together
with the European Union via its COST (Coordination in Science and
Technology) programme and ESA’s General Studies Programme. This
coordination aims to optimise our existing resources (together with our
international partners) in order to develop an operational resource which
will enable society to respond effectively to immediate as well as
long-term changes in our space weather.

For further information, please contact:

ESA Media Relations Service
Tel: +33(0)
Fax: +33(0)

More about …

* SOHO overview

* Cluster overview

* Double Star overview

* Ulysses overview

Related articles

* Enormous X-ray solar flare seen by SOHO

* What are solar flares?

* Massive sunspot faces Earth

* Space weather

* How the Sun affects us on Earth

Related links

* Space Weather

* International Space Environment Service<