Internet reveals solar explosion's target 6-07-99

<font size=1>Monday, June 7, 1999 Published at 18:18 GMT 19:18 UK </font><br><br>

<b><font size=4>Sci/Tech

<p>

Internet reveals solar<br>

explosion's target<p></b></font>

<IMG SRC="http://news.bbc.co.uk/olmedia/360000/images/_363358_sun300.jpg"><br><font size=1><b>



Astronomers did not know if it was heading our way. </b></font><br><br>



<b>By BBC News Online Science Editor Dr David

Whitehouse </b><p>



A tremendous explosion took place on the surface of the

Sun last Tuesday and for a few very nervous hours

astronomers did not know whether it was heading for

Earth.

<p>

The blast threw a jet of superheated plasma carrying

magnetic energy into space at speeds of 1,000

kilometres per second (600 miles per second).

<p>

However, using the speed of the Internet, astronomers

around the world rapidly compared images and decided

that a worldwide alert was unnecessary.

<p>

<b> "Planet-buster"</b>

<p>

<IMG SRC="http://news.bbc.co.uk/olmedia/360000/images/_363358_suni150.jpg" align="left" alt="The aftermath of the explosion"> The Solar and Heliospheric Observer (SOHO) satellite

observed the solar explosion, which astronomers call a

coronal mass ejection (CME).



<p>

The explosive event was "a

real planet-buster", according

to Dr Richard Fisher of

Nasa's Goddard Space Flight

Centre.

<p>

If the magnetic energy within

the cloud of superhot gas

had interacted with the

Earth's magnetic field it

would have sparked

spectacular aurora at polar

latitudes.

<p>

But more worryingly it could also induce power

blackouts, block radio communications and trigger

phantom commands capable of sending satellites

spinning out of their proper orbits.

<p>

Cellular phones, global positioning signals and

space-walking astronauts were all at risk. <p>



<b> Hit or miss?</b>

<p>

"When the coronal mass ejection was observed we were

not sure whether the mass ejection was moving toward

the Earth or directly away from the Earth" said Paal

Brekke, SOHO Deputy Project Scientist.

<p>

Astronomers were particularly concerned that the event

was followed by an increase in the flux of sub-atomic

particles from the Sun.

<p>

So the scientists quickly downloaded Internet images of

the Sun taken by observatories in the USA, Austria,

Australia, and Japan. They then compared images the

taken before and after the event.

<p>

"Because the data are so distributed and so accessible

we were able to identify and track this event," said one

astronomer. "Even just a few years ago, this kind of

instant international collaboration would have been

impossible."

<p>

Fortunately, it was soon established that the CME was

headed directly away from the Earth - this time.

<p>

Preliminary analysis by Dr Simon Plunkett, of the Naval

Research Laboratory in the United States, shows that if

the CME were travelling towards the Earth, it would have

arrived in just two and a half days.

<p>

<b> The other Y2K problem </b>

<p>

Solar activity waxes and wanes in an 11-year cycle,

which is expected to peak sometime early next year.

<p>

Astronomers point out that the solar menace comes at

the same time as computers around the world could

struggle to cope with problems caused by the

Millennium or Year 2000 (Y2K) bug.

<p>

Some solar physicists have called the effects from the

Sun "the other Y2K problem".

<p>

"The SOHO satellite will play a key role in early

detection of solar storms, which is important for issuing

warnings," added Dr Brekke.