Faint Echoes, Distant Stars

by Ben Bova

  Nobel laureate Baruch Blumberg agreed to head the Astrobiology Institute. A medical doctor with a Ph.D. in biochemistry, his research leading to an effective vaccine for hepatitis B earned him the Nobel Prize in 1976. Under his leadership, the Astrobiology Institute now has fifteen research teams under contract, most of them from universities and private research institutions.7 In addition, affiliations have been made with research groups in Spain, the United Kingdom, and Australia. Negotiations are underway for a French group to join, as well.

  Researchers around the world now recognize that the Astrobiology Institute is a prime center of excellence. When the Institute announced that openings were available for three additional organizations, twenty research groups applied.

  “There are many good groups out there,” Blumberg notes. He hopes to add still more affiliates in time.

  Electronic communications have allowed the Institute to stay small. “We keep a low overhead,” he says with pride, “and we have a very good staff.”

  There is still the need to travel, however, and Blumberg is constantly “on the road,” despite his eighty years. He might just as easily be found in the tundra of northern Canada as in the Astrobiology Institute offices at Ames. He sees the Institute’s primary task as building up a large body of basic scientific knowledge that can help NASA to plan missions seeking signs of life.

  “An enormous amount of basic work is needed,” he points out. Still, he expects the astrobiology program to soon begin providing the knowledge needed to develop space-borne instruments and observation tactics.

  Scott Hubbard, who helped found the Astrobiology Institute and served as its first director, is now associate director of Ames. He maintains that the astrobiology program is already making significant contributions to restructuring the missions planned for Mars. Formerly the “Mars czar” at NASA Headquarters, Hubbard said that robotic probes of Mars such as 1997’s highly successful Pathfinder/Sojourner were driven primarily by “hard rock geologists” and atmospheric scientists. Now the astrobiologists are helping the mission planners to prepare future probes that will carry instruments to detect organic chemicals, drill many meters into the Martian crust, and search for water. Astrobiologists are also making contributions to selecting landing sites on Mars and mission objectives.

  Similarly, the new insights of astrobiology are now being fed into the plans for a probe of Europa and other robotic missions to the planets.

  BUDGET WOES

  Yet despite all this, other events intervened to shake all of NASA. Billion-dollar overruns in the costs of the International Space Station triggered another round of belt-tightening throughout the agency. Once again, the rumors coming from Washington hinted that Ames would be shut down. The terrorist strikes on September 11, 2001, threw all of the government’s budgetary matters into upheaval. And Goldin, who had headed NASA longer than any previous administrator, abruptly resigned in October 2001. To take over the agency, President Bush named Sean O’Keefe, a veteran Washington insider whose only previous connection with NASA had been to severely criticize the agency for its cost overruns.

  It seemed clear that O’Keefe had been chosen to bring NASA’s finances under control. He is a former university executive and Secretary of the Navy who had most recently served as deputy director of the Office of Management and Budget (OMB or, in the words of many a scientist, “the bean counters”).

  As O’Keefe assumed the helm at NASA, the agency’s big problem was the International Space Station. First proposed during the Reagan administration, ISS was to be a model of international cooperation on the space frontier, with modules built by the United States, Russia, Japan, and the European Space Agency. ISS was intended to be a station orbiting around the Earth where scientists could study how the human body adapts to long-term conditions of weightlessness and where other experiments could be done on chemical and industrial processes in micro-gravity.

  Instead, ISS has become something of an albatross. Russia has delivered some of the key components of the station but only once the United States supplied the funding that the Russians themselves could not (or would not) provide. In essence, the American government paid Russia to stay in the ISS program. Like many major engineering projects, costs for ISS have ballooned far beyond their original estimates, so much so that the station was limited to only three working astronauts at a time, instead of the originally planned six or more.

  The tragic crash of the space shuttle Columbia on February 1, 2003, threw further confusion and uncertainty into the future of NASA’s research plans. Within a few weeks of the catastrophe, NASA announced that the space station would house only two astronauts at a time, and their research schedule would be reduced from twenty-nine hours per week to twelve.

  Many of the scientific experiments planned for ISS have been postponed or dropped altogether, which infuriates the research community both within and outside NASA. In 2002, an internal NASA committee recommended restricting the space shuttle to four flights to the ISS per year, which would be enough to continue building the station, but it would not be sufficient to support any scientific work. In essence, to save money, the station would become little more than a construction site for five years or more.

  During his confirmation hearing in the senate, O’Keefe said, “The immediate challenges confronting NASA today are, largely, not scientific . . . Rather, the challenges are more aptly described in management terms—financial, contractual, and personnel focused.”

  Much of his senate testimony dealt with the International Space Station’s $4.8 billion overrun and ways to fix it. Asked by Florida Senator Bill Nelson to outline his personal vision for NASA’s future, O’Keefe spoke primarily of applying good business practices to the agency’s management, which will allow NASA to continue its “exploration and technology enterprise and a science-driven agenda.”

  What does this mean for astrobiology? One of O’Keefe’s first moves after being confirmed by the senate was to cut two missions dear to the hearts of the astrobiologists: flights to Jupiter’s moon Europa and the distant-most planet, Pluto. According to White House science advisor John Marsburger, costs for these missions were “going out of control.” Although planned missions to Mars, Venus, and Mercury are still valid, as of early 2003, NASA has no approved missions to the outer planets except for a reinstated mission to Pluto, which still has budget hurdles to clear.

  Instead, O’Keefe has initiated a study of nuclear propulsion for deep-space missions. Nuclear rockets can cut the transit times for missions to the outer planets from years to months. But nuclear rockets face tough political opposition; anti-nuclear protests helped to kill NASA’s nuclear rocket program in the 1970s.

  On the plus side, O’Keefe has proposed a New Frontiers program, aimed primarily at studying the origins of life in the solar system. Funding for New Frontiers missions will be capped at $650 million each, and each mission should take no more than four years to develop. And the Kepler project, aimed at detecting Earth-sized planets orbiting other stars, has been approved for launch in 2006 (see Chapter 17).

  Bruce Jakosky, who heads the University of Colorado’s Laboratory for Atmospheric and Space Physics, one of the fifteen members of the Astrobiology Institute, points out that astrobiology was “protected” under Goldin. Will O’Keefe keep the astrobiology program safe from budget slashing? Ed Weiler, NASA’s associate administrator for space sciences, testified that after fixing the International Space Station’s financial problems, the agency’s prime goal should be to search for evidence of extraterrestrial life.

  Jakosky has arranged a series of public symposia in Boulder, Colorado, about various aspects of astrobiology. He finds that the general public is “really excited” about the search for life in the universe.

  Huntress, now director of the Geophysical Laboratory at the Carnegie Institute of Washington (another Astrobiology Institute member), points out that even if NASA decides to close the Ames center, the Astrobiology Institute and its work wi
ll continue. The Institute can move elsewhere, if necessary. “The results to date are good,” he says, “and talented researchers will find a place for themselves somewhere.”

  Michael Meyer, chief scientist for astrobiology at NASA Headquarters in Washington, says he “can’t imagine cutting astrobiology.” Currently funded at $40 million per year, the program is actually too small to make an impact on NASA’s budget problems, he points out.

  Yet to the researchers in their labs and field stations, this uncertainty can be grueling. It’s as if that scout on the edge of the chasm has just been told that there might not be any more food coming his way and, incidentally, he might have to give up his binoculars, too.

  As of this writing, early in 2003, no one knows how the Astrobiology Institute or Ames Research Center or the International Space Station or NASA itself will fare in the coming years. The outlook is good, but events in the wider world of national and international politics can always intervene. Budgets are a year-to-year thing. But the challenge of learning about life in the universe remains.

  THE WORK GOES ON

  Astrobiology seeks to understand life’s origins, evolution, distribution, and future in the universe. Thus astrobiology includes programs to search for life on other worlds, as well as efforts to determine the origin of life on this planet. Understanding how life began on Earth can give vitally important clues to where and how to look for extraterrestrial life.

  Astrobiology is based on a new attitude, a new approach to the search for understanding life’s role in the universe. It looks into the past to seek out the origins of life. It searches the heavens for evidence of life beyond the Earth. And astrobiologists are also attempting to comprehend what the future of life in the universe will be. In particular, they are examining the problems and possibilities of long-term human existence in space, including the need to build self-sustaining artificial ecologies off-Earth.

  Despite the scientists’ fears and frustrations, despite the threats of budget cuts or a complete shutdown of Ames and other facilities, the work goes on.

  In a greenhouse dubbed the “Archaean Gardens” on the roof of Ames laboratory building 239, shallow pans of water house thin mats of microbial one-celled organisms, the type that first populated the Earth more than 3 billion years ago. Lovingly tended by scientists and technicians, these creatures from the dawn of life are showing the researchers how life changed and adapted to new conditions when our world was young.

  In a computer center, a mathematical physicist is working out the ways by which inert matter became living protein. Down the hall from his office, chemists are putting his theoretical constructs to the ultimate test: Can they produce a living organism out of ordinary water, carbon, and other chemical ingredients? Can they create life in a test tube? Other researchers are simulating ice-coated flecks of dust such as those found in deep space and finding that the first steps in the chemistry of life take place in such ice.

  Not far away, an astronomer is testing a telescope and sensors that will be able to detect Earth-sized planets orbiting distant stars once the equipment is lofted into orbit. Earth-sized planets may be Earth-like enough to harbor life, perhaps even intelligent life.

  Nearby, a lanky bearded scientist is preparing for a trek to Antarctica, where he will search for life in dry frozen valleys and the frigid waters of lakes that are permanently covered by thick layers of ice. He hopes one day to seek life on Mars or on one of the ice-mantled moons of the planet Jupiter.

  THE ULTIMATE QUEST

  What is the history of life?

  Are we alone?

  What is the future of life?

  Seeking the answers to these questions is more than a job, more than a career. As Jakosky puts it, “It’s a spiritual experience.”

  Perhaps the great Renaissance scientist Galileo Galilei put it best:

  [Scientists] seek to investigate the true constitution of the universe—the most important and the most admirable problem that there is.

  The quest will continue.

  Section II

  The Path

  to Life

  on Earth

  6

  The Birth of Our Solar System

  Astronomy is not taught in the public schools . . . a student can pass from first to twelfth grade without ever encountering any of the findings or reasoning processes that tell us where we are in the universe, how we got there, and where we are likely to be going . . .

  —Carl Sagan

  WHILE BIOLOGISTS WERE SLOWLY AWAKENING to the fact that life need not be confined to the surface of a planet, astronomers were struggling with a problem that is of extreme importance to the quest for extraterrestrial life.

  Is our world unique? Is Earth the only planet on which life has arisen? The only planet on which life could arise?

  This question gives rise to a larger one: Is our solar system unique? Is our Sun the only star that is accompanied by a retinue of planets? Or perhaps one of only a very rare, precious few stars that have planets orbiting around them?

  Are other stars accompanied by planetary systems? In Chapter 17 we will see how difficult it is to find planets orbiting other stars, mainly because planets are too small and dim to be seen at the enormous distances of the stars. Giordano Bruno was right: The stars we see at night are other suns; many of them are hundreds, even thousands of times brighter than the Sun. They appear as mere pinpoints of light because they are so far away. If any of them are accompanied by planets, those worlds are simply too far and too dim for us to see them. (However, that does not mean we can’t detect them by other means, as will be shown in Chapter 17.)

  Until Copernicus, most people firmly believed that Earth was the center of the universe, created specially as the abode for humankind. By the third decade of the twentieth century astronomers had discovered that our Earth is only one small planet circling a star that is only one smallish member of the 100 billion or more stars of the Milky Way galaxy, and the Milky Way is only one of billions of galaxies.

  Do any of those other stars have planets? Perhaps we are unique, after all.

  The astronomers were like that scout at the edge of the chasm: Their best instruments could not give them the information they so desperately wanted.

  Faced with a lack of hard data, scientists do exactly what a detective would do when solid information is not available: They try to build a mental picture of what happened, based on the evidence that is available. They do not strike out blindly in the dark and build their conjectures on wild guesses. They use what little they know as clues to help them create a set of ideas, a supposition that is based on the available facts. Then they test the supposition to see (a) if it contradicts any of the available facts, and (b) if it leads to new discoveries.

  Scientists call such a set of ideas a theory. In science, theories are based on data. They are attempts to make sense out of the available facts and also to point the way to new lines of investigation. In science, “theory” does not mean an unproven guess or a wild stab in the dark. Theories are the intellectual framework on which scientific discoveries are arranged to make sense out of the available information and point the way to new areas of discovery. Theories are intended to shed light onto the darkness of ignorance.

  Unable to directly detect planets circling other stars, the astronomers had to create theories, informed speculations based on known data, about how our solar system originated. Then they tested those theories against what was known, in an effort to either prove or disprove them. In science, ideas must be testable to be taken seriously. Only ideas that succeed in passing the tests applied to them are taken as valid.

  EVOLUTION OR CATASTROPHE?

  The earliest attempt at a scientific explanation for the origin of the solar system was made in 1755 by the German philosopher Immanuel Kant (1724–1804). He proposed the nebular hypothesis. His ideas were refined some forty years later by the French mathematician, astronomer, and physicist Pierre-Simon Marquis de Laplace (1749–1827).r />
  The nebular hypothesis suggested that the solar system began as a cloud—a nebula, in astronomical parlance—surrounding the Sun. The gas condensed, solidified, and formed the planets, moons, asteroids, and comets of our solar system. Such a process was believed to be a natural occurrence, an evolutionary sequence that could be expected to take place around other stars. In the Kant/Laplace theory, the solar system is not unique; other stars should be expected to form planetary systems just as our Sun did.

  The sharp edge of mathematical fact burst this theoretical balloon. The Scottish physicist James Clerk Maxwell (1831–1879), one of the supergiants of science, proved mathematically that such a gas cloud would simply not behave the way the nebular hypothesis demanded. Maxwell showed that if all the matter in the now solid bodies of the solar system—planets, moons, etc.—was originally gaseous, the gas cloud would have been far too thin to condense into planets. Instead of condensing like milk, lumping up and turning into cheese, the gas cloud would have wafted away and dispersed into space.

  By the late nineteenth century the evolutionary explanation of the nebular hypothesis was thoroughly discredited. It was replaced by what has been called the tidal or stellar encounter hypothesis. A quartet of scientists, two in America and two in Britain, worked out slightly different versions of this idea. The British were Sir James Jeans (1877–1946) and Sir Harold Jeffreys (1891–1989). Jeans was an astrophysicist and an accomplished writer of science books for the general public. Jeffreys was a geophysicist and astronomer. The Americans were geologist Thomas Chrowder Chamberlin (1843–1928) and astronomer Forest Ray Moulton (1872–1952).

  Interstellar Distances

  Although the details of their theories differ slightly, all four envisioned the solar system originating as the result of an interstellar encounter, a near collision between the Sun and a passing star. The “rogue star” passed close enough to the Sun to yank out a massive filament of gaseous material, which then condensed to form the planets and other solid bodies of the solar system.