The Department's last big project is its X-ray lab, where scientists study the insides of crystals, learning how the molecules are put together.

Geologists are studying the shape of some of the smallest things in the Universe; and astronomers are studying the shape of one of the largest--the Milky Way galaxy.

Road-Map of the Universe

Professors Bart J. Bok and Harlow Shapley are trying to map this huge disc-shaped "island universe," which includes the earth and every star that the naked eye can see. Both of them are measuring the distance to far-away suns, to determine their relative positions in the galaxy and thus the shape of the galaxy itself.

Bok measures the distance of a star by studying its color, which changes as the light passes through the dust clouds of space. Shapley looks at variable stars, which grow brighter and dimmer with a regular period. This period often depends on the absolute brightness of the star; when Shapley knows the absolute brightness and the brightness as seen from the earth, he can easily determine the star's distance.

Chamelon Stars

Professor Armin Deutsch is investigating another kind of variable star, which regularly changes color. Only 20 of them are known, and to astronomers the varying spectrum suggests that millions of tons of calcium are changing into other chemicals. So far Deutsch has not found much--only that these stars are surrounded by strong magnetic fields; 5000 times greater than the earth's.

From the biggest astronomical bodies to the smallest--that takes one to the work Professor Fred L. Whipple, who studies the miner bodies of the solar

This is the third in a series of four articles on Harvard's scientists and what they are doing. It covers the Geology and Astronomy Departments. system; meters, comets, and dust. A caravan of trucks--"Whipple's Wagon Train"--is now touring the Southwest, snapping pictures of meteors every night to discover their evolution and habits.

From the cosmic dust, Whipple has drawn a theory on the origin of the earth-now probably the ranking theory among astronomers. He hypothesizes that the solar system was once all dust, and that the dust collected to form planets. And what, at first, drove the dust together? Not gravity, says Whipple, and not molecular attraction--but the seemingly insignificant push exerted by light beams, streaming out from the sun