Death from the Sun

In cosmic terms, humans may be uncomfortably like those pale, soft-bodied insects that live under stones and dare not venture into the open. For it is becoming increasingly apparent that man is not going to be able to venture beyond the shelter of the earth's protecting atmosphere unless he develops massive, mechanical shells to protect his vulnerable body from the searing hazards of outer space.

Latest discovered hazard, and potentially the most dangerous yet, was described last week by Physicists E. P. Ney, J. R. Winckler and P. S. Freier of the University of Minnesota, who specialize on observing cosmic rays by means of high-altitude plastic balloons. Last May 10 they heard from astronomers that an unusually powerful flare had erupted on the sun. As they readied their great balloons, a telephone call came from Alaska; Astrophysicist Harold Leinbach was reporting that his radio telescope at College (near Fairbanks) had detected a sudden blackout of radio noise from space. This indicated, said Leinbach, that a great swarm of particles from the sun was hitting the atmosphere.

Blasts from Space. During the night of May 11-12, five balloons rose into the sky from the university's airport at Anoka, 20 miles north of Minneapolis. At 60,000 ft. their instruments began to register intense blasts of radiation. Study of the instrument packages at the University of Minnesota showed that the radiation was made of speeding protons from the sun. The radiation was about 1,000 times as intense as the cosmic rays that normally come from space. Unlike the Van Allen radiation, which is made of solar protons that have been trapped by the earth's magnetic field and forced to zigzag around the earth, the balloon-detected particles came directly from the sun, crashing into the earth's atmosphere with energies between no million and 120 million electron-volts.

On July 14 another series of balloon-borne instruments detected an even hotter burst of radiation, about 10,000 times more intense than normal cosmic rays. Both the May and July radiation bursts, say the Minnesota scientists, came from the same disturbed region on the sun, which has been exploding for many months like a vast ammunition dump. As the sun rotates, flare after flare has sprayed streams of particles into space, sweeping the solar system like streams of water from a revolving lawn sprinkler.

No Polar Exits. When the doughnut-shaped Van Allen radiation belts were discovered (TIME, May 12. 1958), optimists predicted that unshielded space vehicles could avoid them by taking off on space voyages by way of the "holes"' over the polar regions. But the deadly, invisible streams of the new-found radiation lash through the polar holes, as well as through the whole solar system. Space vehicles making the short run to the moon may be able to pick quiet intervals between the flares, but voyages to Mars or Venus will take several months. During this considerable period a flare is likely to spray the ship and fry its passengers unless they are protected by tons of shielding material.

Best hope for unshielded space travelers : the flares may die away during the low points of the eleven-year sunspot cycles, the first of which should come in about five years.

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