Cream of the Milky Way

On a hill where Aztec priests once studied the stars, President Manuel Avila Camacho of Mexico dedicated a great modern observatory. Tonanzintla, near Puebla, 70 miles southeast of Mexico City, was the envy of visiting U.S. astronomers because of its latitude. Harvard's Harlow Shapley explained, "All the Milky Way can be seen--not merely the 60% or less which is satisfactorily explored from most northern observatories."

Before returning to their dimmer skies last week, the U.S. stargazers swapped discoveries with their Mexican hosts:

Star Dust into Stars. In great interstellar clouds of dust, new planets and stars are now being formed (Fred L. Whipple of Harvard). In the Milky Way system, in which Earth is one of the most inconsiderable planets, star dust and gas contain as much matter as all the known stars. To congeal into stars, these 1/250,000-inch dust particles would require more billions of years than the calculated age of the universe--were it not that gravitation and the pressure of light whirl the dust in cur rents and thus speed up its condensation so immeasurably that Whipple "expects to witness the birth of highly luminous and massive super-giant stars." Cosmic radio signals, which physicists have traced to the Milky Way, can also be explained by these dust currents, Whippie thinks. As the electrified particles whirl about, they are capable of generating the mighty eleven-meter "static" waves which sometimes interfere with earthly communication.

Rotation of stars has also puzzled astronomers. Otto Struve of the University of Chicago weeded hypotheses down to this one : that stellar rotation too is caused by interstellar dust, colliding like hail stones with the stars. While the sun rotates with a velocity at its equator of only* Messier 51 in Canes Venatici (The Hounds) twelve miles per second, the stars of Aquila whirl at 9,360 miles per second. At such speeds, stars become unstable and shed rings of hot gas. Thus, as some stars are born of dust, others are destroyed by it.

Streams of stars, which extend in spiral arms from three-fourths of the other galaxies (comparable to our Milky Way), have hitherto been considered ejections flung from the galactic center (see cut). But no, quite the contrary, announced Harlow Shapley. The galactic tentacles are really condensations, and four-fifths of a spiral galaxy's light comes not from its arms but from the background material out of which the arms have curdled.

The Sun travels around the center of the Milky Way at 109 miles per second, i.e., 36% slower than astronomers formerly computed (Nicholas U. Mayall of the University of California)--if the far-off globular star clusters, against which he measured the Sun's motion, are themselves motionless. Mayall also confirmed "earlier evidence that our entire Milky Way is in rapid rotation around the distant center of Sagittarius." But he now suspects that the entire Milky Way may weigh only half as much as observers have believed. Sighed a New York Times headline: "Earth's Significance Diminishes."

This file is automatically generated by a robot program, so reader's discretion is required.