Things hot up as Sun goes into frenzy

Press, 18 March 1989, Page 18

Things hot up as Sun goes into frenzy

NZPA-AFP Paris Things, are hotting up out there in the Earth’s backyard, as the Sun goes into one of its periodic frenzies, and blasts out radiation energy so strong that it sends scientists’ instruments right off the scale.

The present series of massive disturbances on the sun is “a big one, with perhaps the most intense eruption ever observed,” said Mr Pierre Lanthos, the astronomer in charge of solar affairs at the Meudon observatory near Paris.

The eruptions, littleunderstood phenomena which involve massive fluctuations in the sun’s magnetic field and tern-

perature, started ait the beginning of March, Mr Lanthos said.

One eruption on March 6 “was the most powerful for the emission of X-rays ever seen,” he said, adding that “it swamped our measuring instruments.”

Then on March 9 a new explosion exceeded all previous known measurements on the four-point brilliance scale established for such events, the astronomer said, citing American scientists at the Holloman air base in New Mexico.

Solar eruptions, which often involve changes in the so-called "sunspots” on its surface, result from the violent fusion process which is going on continually inside the Sun.

Temperatures range from some 15 million deg. C at the Sun’s core to 5750 deg. C in the “photo sphere” surrounding the star. The sunspots are positively cool by comparison, a mere 3000 deg. C. Pascal Sotirovski, a sunspot specialist at Meudon, said that the Sun had a regular cycle of activity, which lasts about 11 years. It was now at the end of one cycle, and beginning another. The eruptions can sometimes affect life on Earth, by sending out blasts of high-frequency X-rays and ultra-violet light, which modify the upper parts of the Earth’s ozone layer and can cause serious interference to radio signals, Mr So-

tirovski said. The solar disturbances also send massive blasts of particles, mainly protons and electrons, hurtling towards Earth. They are stopped by the atmosphere, but if, for example, a group of astronauts in a spacecraft happened to be in their way they could be burnt to a frazzle. The particles are followed by the eruption’s shock wave, the so-called “solar wind,” which plays havoc with the Earth’s magnetic field, and at the same time causes the beautiful "aurora borealis” in northern skies and the “aurora australis” in the southern skies.