Thin ‘wind’ from space could alter climate

Press, 8 February 1985, Page 19

Thin ‘wind’ from space could alter climate

NZPA-AP Tuscon, Arizona An exceedingly thin “wind” blowing through the solar system could carry material that would produce world-wide rains and sharply alter the climate on Earth, a researcher says. If the prediction is correct, the climatic changes would occur 250,000 years from now, said Ms Priscilla Frisch, an astronomer from the University of Chicago. “I have this stored in my file as long-range weather forecasting,” said Ms Frisch.

She made the admittedly speculative prediction recently at a symposium entitled “The Galaxy and the Solar System”, sponsored by the University of Arizona. Ms Frisch said her presentation, prepared in collaboration with Mr Donald York, another University of Chicago astronomer, was a compilation of research done driving the last few years by many scientists. Observations had shown

that the Earth and the rest of the solar system were now in the edge of a very thin cloud of interstellar material blowing towards us at a speed roughly 16km a second, Ms Frisch said. The cloud producing the "local interstellar wind,” as she called it, was composed mostly of hydrogen atoms with trace amounts of many other elements. It could also contain a core perhaps 10,000 times as dense as the wind now blowing past the solar system.

“We certainly know that such denser material exists elsewhere,” she said. The light solar wind now blowing through the solar system did not affect the Earth, because the Earth was shielded by the stronger solar wind, coming from the sun. The solar wind however, might not protect Earth from the cloud’s dense core.

“As the cloud gets denser and denser, more of this

material penetrates the solar system without getting destroyed,” Ms Frisch said.

If the core came into contact with the Earth’s atmosphere, the hydrogen atoms in it would combine with oxygen in the atmosphere to form water. “The result would be a big rainfall,” Ms Frisch said.

The trace elements in the cloud’s core could alter the chemistry of the atmosphere, and the core would reduce the amount of ultraviolet radiation reaching Earth, another change that would alter the atmosphere, she said.

The cloud could now be measured. It is large enough to cover about a quarter of the sky and its core — if it exists — might be less than 15 light-years away, she said. (A light-year, the distance light travels in a year, is about 9.6 trillion kilometres), '