THE INHABITANTS OF JUPITER “must … it would seem, be cartilaginous and glutinous masses…. boneless, watery, pulpy creatures.” Thus, 121 years ago, did the British philosopher William Whewell speculate on the kind of beings that might live in the powerful gravitation of the largest planet of the solar system.
Whewell’s description may seem farfetched to¬day, but not his suggestion that life could exist on Jupiter. Indeed, in recent years some scientists have suggested that conditions for the origin of life may be quite favorable on the huge planet, despite its seemingly hostile environment.
Interest in this possibility has heightened now that American space probes have begun exploration of Jupiter. Only a few weeks before you read this, a spidery spacecraft named Pioneer 11 will have raced swiftly through the frightful radiation belts of Jupiter, aiming its battery of 12 instruments at the strange Jovian environment. Almost exactly a year earlier, Pioneer 10 preceded it, sending back to earth remarkable images of the huge multicolored cloud bands that ring the planet, the swirling storms, and the enigmatic Great Red Spot.
Pioneer 10 could not see evidence of life from its closest distance of 82,000 miles above the cloud tops, nor was it designed to detect life. Neither could Pioneer 11, though it passed within 27,000 miles. But as scientists analyze the data transmitted by these spacecraft about atmosphere, temperatures, gravity, radiation, and magnetic fields, they are putting together new models of Jupiter that have implications about the possibilities of life.
Astronauts will not likely put these figures to the test anytime in the foreseeable future, however. The difficulties and hazards of a manned voyage to Jupiter would defeat today’s most advanced technology. Few men would welcome the sheer dura¬tion of the trip-21 months for Pioneer 10—even if life-support equipment were devised to last that long. Communications would be a problem, especially for a stricken spacecraft —some 45 minutes each way for messages flying at the speed of light.
But the chief peril comes from Jupiter’s vicious radiation belts. Pioneer 10, in the few hours of its closest approach to the planet, received a massive and unexpectedly high dose of radiation, a thousand times the lethal amount for a human being. Although the spacecraft itself came through relatively unharmed, with few of its instruments more than temporarily affected, engineers believe it was at the very limits of its tolerance to damage from the high-energy electrons that fill the radiation belts.
Eventually scientists will send an un¬manned space probe plunging into the Jovian atmosphere. What its sensors will detect, and what you might see if you were aboard, can be speculated about, thanks to the latest theories concerning the atmosphere and in¬terior of Jupiter. Some of these new ideas were announced just as this article was written.