California Ins(itu(e of Technology Engineering & Science Spring 1989 In this issue Seeking other worlds Preserving our own world New world of research In November 1982, these two teenagers were lost for nearly a week in the Wash­ ington wilderness. With little hope of being seen, let alone survlvmg. At night, they huddled together for warmth, so nei­ ther would freeze. But their body heat drew them even closer to safety. This is a picture of 2 lost boys in a 20,000 acre forest. They were spotted from a rescue helicopter equipped with an extraordinary infrared scanning device. The Probeye' thermal imager, developed by Hughes Aircraft Company. It records heat, just as photo­ graphy records light. In this case, by detecting body heat, it helped rescuers penetrate the dense snow-covered forest to save the stranded boys. It was the only chance they had. We at Hughes are dedicated to developing innovative tech­ nologies. And whether it's to defend the Free World or extend the freedom of thought, we're always expanding our vision. To save two lives, or enhance the quality of life throughout the world. HUGHES AIRCRAFT COMPANY © 1987 Hughes Aircnlft Company Subsidiary of GM Hughes Electronics California Institute of Technology Engineering & Science Spring 1989 Volume LU, Number 3 2 Prospecting for Planets - by Richard]. Terrile Do other solar systems exist? They almost certainly do, and new techniques to reduce diffracted and scattered light may enable us to find them. 10 Where Are Our Efforts Leading? A conference honoring Murray Gell-Mann's birthday invited a group of eminent guests to speculate on the state of the world (and of physics) in the coming decades. 22 Beckman Institute Becomes Concrete Its resource centers should make fundamental contributions to chemistry and biology. E&S looks at what the centers are and how they got there. Departments 35 Obituaries: Frederick Lindvall, Paco Lagerstrom 38 Lab Notes: Hooked on Proteins 40 Books: Mirror in the Shrine: American Encounters with Meiji Japan by Robert Rosenstone 41 Letters 43 Random Walk On the cover: A self­ Engineering & Science (ISSN 0013-7812) is published quarterly, Charles H. Holland, Jr. reproducing cellular Fall, Winter, Spring, and Summer, at the Califomia Institute of President of the Alumni Association Technology, 1201 East California Boulevard, Pasadena, Califomia automaton creates a Theodore P. Hurwitz colony consisting of a 91125. Annual subscription $8.00 domestic; $20.00 foreign air mail; single copies $2.00. Third class postage paid at Pasadena, Vice President for Institute Relations "live" reproductive California. All rights reserved. Reproduction of material contained Robert 1. O'Rourke fringe around a grow­ herein forbidden without authorization. © 1988 Alumni Associa­ Assistant Vice President for Public Relations ing "dead" core, simi­ tion, California Institute of Technology. Published by the California lar to a coral reef. Institute of Technology and the Alumni Association. Telephone: STAFF: Editor - Jane Dietrich 818-356-3630. Postmaster: Send change of address to Caltech Such "artificial life" Writer - Douglas Smith was one speaker's 1-71, Pasadena, CA 91125. Copy Editors - Michael Farquhar, answer to "Where Are PICTURE CREDITS: Cover, 20 - Chris Langton; Our Efforts Leading?" Julie Hakewill, Betsy Hatch 2-9 - JPL; 10-16,26,28,30,31,39 - Roberr Paz; Production Artist - Barbara Wirick Other steps in this 17 - John Allman; 18 - Lydia Matthews; 19 - Dave Business Manager - Debbie Bradbury process (courtesy of Sivertsen; 21 - Valentine Telegdi; 22 - Douglas Smith; Chris Langton of Los 24, 25, 27, 29, 30, 32, 34 - Alberr C. Martin and Circulation Manager - Susan Lee Alamos National Lab) Assoc.; 26 - Mike Harrington, Carl Merril; 32 - Mike Photographer - Robert Paz are shown on page Sailor, John Armsttong; 33 - Reggie Penner, Mike 20. Heben; 35 ~ Jim McClanahan; 37 - Richard Kee; 38 - Frances Arnold. 2 Engineering & Science/Spring 1989 Prosp~cting for Planets The obvious next step is to go from explor­ ing the planets to exploring the . by Richard J. Terrile nearby stars and whatever worlds might exist around them. What will be the next big adventure in radio signals are being broadcast from them. space? We have sent men to the moon-about And of course we've been broadcasting our own 200,000 nautical miles away. We've landed "intelligent" radio signals for about 40 years spacecraft on Mars, about 500 times farther now-television broadcasts, which have left the away. And with the Voyager spacecraft we've ionosphere of Earth and are now expanding at also visited the outer regions of the solar the speed of light in a shell about 40 light-years system-lO,OOO times farther away than the in radius. Within that shell there are about 800 moon. The obvious next step is to go from different star systems, and the broadcast shell is Evidence of what may exploring the planets to exploring the nearby now crossing a new star system about every three be a planetary system stars and whatever worlds might exist around days. So every three days there's a new oppor­ orbiting the star Beta tunity for somebody out there to say, "Ah, The Pictoris, about 50 them. light- years away, Humans have always been curious about the Gale Storm Show.'" It's an intriguing thought. shows up in this night sky. When man realized the relationship Twenty years ago, when this shell was only half image made in 1984 as large, it was crossing a star system about every by Richard Terrile and between the sun in the daytime sky and the stars Bradford Smith, using in the night sky, it was a fundamental connec­ two weeks. If somebody in one of those star sys­ the 100-inch tele­ tion in human thought. We are now at another tems had then said, "Aha, there's life on Earth; scope at Las Campa­ let's broadcast a reply," and had beamed a nas Observatory. The threshold-where technology has caught up with perpendicular lines curiosity, and it's very exciting to be there. We strong reply signal, then 20 years after that­ are caused by fine silk now know enough about the theory of planetary today or tomorrow-we might be receiving filaments that support that reply on our arrays of radio telescopes. an occulting mask. formation and the evolution of stars to indicate This mask removes that perhaps planetary formation is a common But there will be only a short, finite period of most of the star's phenomenon-the norm and not the exception. time when the Earth is broadcasting its existence diffracted light that as an intelligent civilization. We're becoming normally would hide And although the nearest stars are about 10,000 the circumstellar disk times farther away than the outer planets of our much more efficient in transmitting communica­ from view. solar system and it would take tens of thousands tion around our planet and are adopting fiber of years to visit them with a spacecraft, we're at optics, instead of broadcasting all this energy that least beginning to understand what it takes to leaks out past our atmosphere. So, perhaps directly image planets around other stars. And this isn't the best way to look for life on other we can now build what it takes. planets. The Earth has been around for 4Y2 bil­ Up until now we've been attempting in other lion years and we've only been broadcasting for ways to discover whether we're alone in the 40. If others aren't actively signaling their universe. We are using radio telescopes for a existence but just accidentally broadcasting until program mlled SETI, the Search for Extraterres­ their technology gets better, the odds are 1 in trial Intelligence. In this program we listen to 100 million that we'll connect. the other stars to see if any kind of intelligent Our galaxy, like others, contains about 200 Engineering & Science/Spring 1989 3 Jupiter-sized planets among the 200 billion stars of the Milky Way could be very common-perhaps even the rule rather than the e xception. billion srars. To get an idea of what 200 billion srars might look like, we can make a model of a galaxy on the floor, using grains of salt to represent [he stars. (This is an experiment you should try at home. It's safe; it's nontox.ic; you don' [ need to wear goggles or any safety equip­ ment; and you can do it unsupervised as long as you clean up afterwards.) A concainer of sale that you can buy for 25 cems contains about 5 million grains. It turns oue chat we would need a carload of salt (200 containers) to make a bil­ lion stars on our floor, and in order co get enough to represent all the srars in the galaxy, we would need a whole trainload of salt. To spread chis trainload of sale out to make our model, we 'll have to calculate how far away each grain has co be from its neighbots. We know how fat away the stars are, and we know how big they are, so we can figure this our easily enough. (In this model, with our Sun a gtain of salt, the Earth is about 2 inches away from it, and Jupiter would be about 10 inches away and would be the size of a mote of dust.) In our model the stars themselves-the grains of salt­ would have to be sepatated by about 7. 5 miles. (You can understand why stars tarely collide.) The floot I would need to spread them out on would be about one and a half times the dis­ tance between Earth and the Moon.