Cosmic Connection Read Free Page B

sky?

    One of the two stars that Project Ozma examined a decade ago for possible extraterrestrial intelligent signals was Tau Ceti, in the constellation (as seen from Earth) of Cetus, the whale. In the accompanying figure, the computer has drawn the sky as seen from a hypothetical planet of T Cet. We are now a little more than eleven light-years away from the Sun. The perspective has changed somewhat more. The relative orientation of the stars has varied, and we are free to invent new constellations–a psychological projective test for the Cetians.

    I asked my wife, Linda, who is an artist, to draw a constellation of a unicorn in the Cetian sky. There is already a unicorn in our sky, called Monoceros, but I wanted this to be a larger and more elegant unicorn–and also one slightly different from common terrestrial unicorns–with six legs, say, rather than four. She invented quite a handsome beast. Contrary to my expectation that he would have three pairs of legs, he is quite proudly galloping on two clusters of three legs each, one fore and one aft. It seems quite a believable gallop. There is a tiny star that is just barely seen at the point where the unicorn’s tail joins the rest of his body. That faint and un-inspiringly positioned star is the Sun. The Cetians may consider it an amusing speculation that a race of intelligent beings lives on a planet circling the star that joins the unicorn to his tail.

    When we move to greater distances from the Sun than Tau Ceti–to forty or fifty light-years–the Sun dwindles still further in brightness until it is invisible to an unaided human eye. Long interstellar voyages–if they are ever undertaken–will not use dead-reckoning on the Sun. Our mighty star, on which all life on Earth depends, our Sun, which is so bright that we risk blindness by prolonged direct viewing, cannot be seen at all at a distance of a few dozen light-years–a thousandth of the distance to the center of our Galaxy.

3. A Message from Earth
    M ankind’s first serious attempt to communicate with extraterrestrial civilizations occurred on March 3, 1972, with the launching of the Pioneer 10 spacecraft from Cape Kennedy. Pioneer 10 was the first space vehicle designed to explore the environment of the planet Jupiter and, earlier in its voyage, the asteroids that lie between the orbits of Mars and Jupiter. Its orbit was not disturbed by an errant asteroid–the safety factor was estimated as 20 to 1. It approached Jupiter on December 3, 1973, and then was accelerated by Jupiter’s gravity to become the first man-made object to leave the Solar System. Its exit velocity is about 7 miles per second.
    Pioneer 10 is the speediest object launched to date by mankind. But space is very empty, and the distances between the stars are vast. In the next 10 billion years, Pioneer 10 will not enter the planetary system of any other star, even assuming that all the stars in the Galaxy have such planetary systems. The spacecraft will take about 80,000 years merely to travel the distance to the nearest star, about 4.3 light-years away.
    But Pioneer 10 is not directed to the vicinity of the nearest star. Instead, it will be traveling toward a point on the celestial sphere near the boundary of the constellations Taurus and Orion, where there are no nearby objects.
    It is conceivable that the spacecraft will be encountered by an extraterrestrial civilization only if such a civilization has an extensive capability for interstellar space flight and is able to intercept and recover such silent space derelicts.
    Placing a message aboard Pioneer 10 is very much like a shipwrecked sailor casting a bottled message into the ocean–but the ocean of space is much vaster than any ocean on Earth.
    When my attention was drawn to the possibility of placing a message in a space-age bottle, I contacted the Pioneer 10 project office and NASA headquarters to see if there were any likelihood of implementing this suggestion. To my surprise