Scientists Take Temperatures of Sun's Corona, Yellowstone's Geysers

Harvard's astronomers are looking up in the sky, and for geologists are looking down in the ground. Both are looking for the same thing.

In each department, men are interested in the temperatures of things they can't touch, Professor Donald H. Menzel wants to explain the temperature of the corona, a collar of thin gas around the sun. Professor Louis C. Graton wants to find the temperature of geyser holes.

Menzel, whose thermometers must reach 93,000,000 miles, seems to have the tougher job. The temperature of the sun is 6000 Centigrade, but the temperature of the corona, which the naked eye can see only during total eclipses, appears to be 1,000,000. That's what Menzel is trying to explain, but it's only one of his worries.

The Sun Edits a Telegram

His chief problem is how the sun affects the early--why radios go on the blink when sunspots are heavy, for instance, and why a big tongue of fire on the sun will change the words on a telegram.

To solve all this, Menzel directs a cone-roofed observatory in Colorado, and a new station in New Mexico, close to the site of the first atom bomb. The observatories are equipped with spectrohelioscopes-- astronomical X-ray machines that penetrate to the inner layers of the sun--and with coronoscopes, which blot out the sun like an eclipse, so that the other corona can be watched. Menzel went west a few months ago to spend all his time at the solar stations, on the Astronomy Department's biggest project.

Professor Graton also goes west for his work--out to Yellowstone National Park and the geyser country. Last summer he wired up a cable with six electric thermometers, all recording simultaneously on a remote sheet of graph paper. He carried the device all over Yellowstone, and lowered it down the gullet of every geyser he could find.

Graton wanted to see how temperatures changed at various depths as the geyser went off. But once his experimenting brought up more than a handful of pen-line graphs.

It happened last summer, when Graton had dropped his cable into Old Faithful, to study the temperature of the world's most famous geyser. Suddenly his instruments tripped some unknown underground trigger, and Old Faithful-- which had faithfully erupted every 63 minutes since the Indians found it--blew its top 15 minutes too soon. Graton and his party didn't know the geyser was loaded, but they backed out of the way before anyone was hurt.

From the information gathered in Yellowstone, the geologists have prepared a Walt Disneyish movie, caricaturing a geyser and pointing out its temperature shifts. By these methods they hope to solve the mysteries of where the heat and the water comes from.

Graton works in hot ground. His fellow Department member, Professor Kirk Bryan, is an expert in cold ground. Bryan is doing research in the permanently frozen soil of Alaska, which presents problems to men building things like the Alcan highway.

But the best-known projects in the Geology Department are the seismographs of Professor L. Don Leet. Last Month Leet wrote earthquake history by picking up a dynamite explosion in South Holston, Tennessee--the farthest distance a man-made noise has ever been "heard."

681 Tons of TNT

The Tennessee Valley Authority had to touch off 681 tons of TNT before Lect's instruments could feel it, though. The blast ripped out one side of a mountain to supply crushed rock for a TVA dam. Present seismographs, says Leet, have never recorded an atom bomb explosion.

Working in an abandoned garage, Leet has developed a new labor-saving seismograph, which frees geologists from darkrooms and sub-cellar laboratories. Old seismographs recorded on photographic plates; the new one relays earth tremors to a pen-and-paper graph on Leet's desk.

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