dipper@utastro.UUCP (Debbie Byrd) (11/23/85)
People who work in outer space have to stay alert to a kind of space "weather forecast." More -- in just a moment. November 23 Storms from the Sun Now that people are routinely working out in space, they have to get used to new hazards -- including the threat of storms from the sun. These storms in space are caused by solar flares -- events that take place on the sun -- when our usually benign mother star shows an area that's very bright in X-rays, ultraviolet and visible light. The flare ejects a gas cloud that travels at nearly four thousand miles per second -- and that reaches Earth in about a day. Then people on the surface of Earth are treated to the sight of the aurora, or northern and southern lights. Meanwhile, people in Earth-orbit would be buffeted by cosmic rays, streams of protons, and heavier nuclear particles with enough energy to penetrate metal. Someone working in space -- protected only by a spacesuit -- could be made ill or even killed by radiation from a giant solar flare. Fortunately, the flares can be seen from Earth when they occur -- and their effects take about a day to arrive. With plenty of warning, space workers can take cover whenever a dangerous solar storm is on the way. There are fewer such storms this year than a few years ago -- because we're close to a solar minimum -- a time in the ll-year cycle of solar activity when that activity is at a low ebb. The solar minimum is predicted for l988 -- and afterwards the sun will start getting more active again -- with an increase in sunspots and flares -- predicted to reach another maximum in late l99l. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin