Death by Black Hole: And Other Cosmic Quandaries (30 page)

The English physicist Michael Faraday discovered electromagnetic induction in 1831, which enabled the first electric motor. The farad, a measure of a device’s capacity to store electric charge, probably doesn’t do full justice to his contributions to science.

The German physicist Heinrich Hertz discovered electromagnetic waves in 1888, which enabled communication via radio; his name survives as the unit of frequency along with its metric derivatives “kilohertz,” “megahertz,” and “gigahertz.”

From the Italian physicist Alessandro Volta we have the volt, a unit of electric potential. From the French physicist André-Marie Ampère, we have the unit of electric current known as the ampere, or “amp” for short. From the British physicist James Prescott Joule, we have the joule, a unit of energy. The list goes on and on.

With the exception of Benjamin Franklin and his tireless experiments with electricity, the U.S. as a nation watched this fertile chapter of human achievement from afar, preoccupied with gaining its independence from England and exploiting the economies of slave labor. Today the best we could do was pay homage in the original
Star Trek
television series: Scotland is the country of origin of the industrial revolution, and of the chief engineer of the starship
Enterprise
. His name? “Scotty” of course.

In the late eighteenth century the industrial revolution was in full swing, but so too was the French Revolution. The French used the occasion to shake up more than the royalty; they also introduced the metric system to standardize what was then a world of mismatched measures—confounding science and commerce alike. Members of the French Academy of Sciences led the world in measures of the Earth’s shape and had proudly determined it to be an oblate spheroid. Building on this knowledge, they defined the meter to be one ten-millionth the distance along the Earth’s surface from the North Pole to the equator, passing through—where else?—Paris. This measure of length was standardized as the separation between two marks etched on a special bar of platinum alloyed with iridium. The French devised many other decimal standards that (except for decimal time and decimal angles) were ultimately adopted by all the civilized nations of the world except the U.S., the west African nation of Liberia, and the politically unstable tropical nation of Myanmar. The original artifacts of this metric effort are preserved at the International Bureau of Weights and Measures—located, of course, near Paris.

BEGINNING IN THE
late 1930s the U.S. became a nexus of activity in nuclear physics. Much of the intellectual capital grew out of the exodus of scientists from Nazi Germany. But the financial capital came from Washington, in the race to beat Hitler to build an atomic bomb. The coordinated effort to produce the bomb was known as the Manhattan Project, so named because much of the early research had been done in Manhattan, at Columbia University’s Pupin Laboratories.

The wartime investments had huge peacetime benefits for the community of nuclear physicists. From the 1930s through the 1980s, American accelerators were the largest and most productive in the world. These racetracks of physics are windows into the fundamental structure and behavior of matter. They create beams of subatomic particles, accelerate them to near the speed of light with a cleverly configured electric field, and smash them into other particles, busting them to smithereens. Sorting through the smithereens, physicists have found evidence for hoards of new particles and even new laws of physics.

American nuclear physics labs are duly famous. Even people who are physics-challenged will recognize the top names: Los Alamos; Lawrence Livermore; Brookhaven; Lawrence Berkeley; Fermi Labs; Oak Ridge. Physicists at these places discovered new particles, isolated new elements, informed a nascent theoretical model of particle physics, and collected Nobel Prizes for doing so.

The American footprint in that era of physics is forever inscribed at the heavy end of the periodic table. Element number 95 is americium; number 97 is berkelium; number 98 is californium; number 103 is lawrencium, for Ernest O. Lawrence, the American physicist who invented the first particle accelerator; and number 106 is seaborgium, for Glenn T. Seaborg, the American physicist whose lab at the University of California, Berkeley, discovered ten new elements heavier than uranium.

EVER-LARGER ACCELERATORS
reach ever-higher energies, probing the fast-receding boundary between what is known and unknown about the universe. The big bang theory of cosmology asserts that the universe was once a very small and very hot soup of energetic subatomic particles. With a super-duper particle-smasher, physicists might be able to simulate the earliest moments of the cosmos. In the 1980s, when U.S. physicists proposed just such an accelerator (eventually dubbed the Super-conducting Super Collider), Congress was ready to fund it. The U.S. Department of Energy was ready to oversee it. Plans were drawn up. Construction began. A circular tunnel 50 miles around (the size of the Washington, DC, beltway) was dug in Texas. Physicists were eager to peer across the next cosmic frontier. But in 1993, when cost overruns looked intractable, a fiscally frustrated Congress permanently withdrew funds for the $11 billion project. It probably never occurred to our elected representatives that by canceling the Super Collider they surrendered America’s primacy in experimental particle physics.

If you want to see the next frontier, hop a plane to Europe, which seized the opportunity to build the world’s largest particle accelerator and stake a claim of its own on the landscape of cosmic knowledge. Known as the Large Hadron Collider, the accelerator will be run by the European Center for Particle Physics (better known by an acronym that no longer fits its name, CERN). Although some U.S physicists are collaborators, America as a nation will watch the effort from afar, just as so many nations have done before.

A
strophysics reigns as the most humbling of scientific disciplines. The astounding breadth and depth of the universe deflates our egos daily, and we are continually at the mercy of uncontrolled forces. A simple cloudy evening—one that would stop no other human activity—prevents us from making observations with a telescope that can cost $20,000 a night to run, regardless of the weather. We are passive observers of the cosmos, acquiring data when, where, and how nature reveals it to us. To know the cosmos requires that we have windows onto the universe that remain unfogged, untinted, and unpolluted. But the spread of what we call civilization, and the associated ubiquity of modern technology, is generally at odds with this mission. Unless we do something about it, people will soon bathe Earth in a background glow of light, blocking all access to the frontiers of cosmic discovery.

The most obvious and prevalent form of astropollution comes from streetlamps. All too often, they can be seen from your airplane window during night flights, which means that these streetlamps illuminate not only the streets below but the rest of the universe. Unshielded streetlights, such as those without downward-facing shades, are most to blame. Municipalities with these poorly designed lamp housings find themselves buying higher-wattage bulbs because half the lamplight points upward. This wasted light, shot forth into the night sky, has rendered much of the world’s real estate unsuitable for astronomical research. At the 1999 “Preserving the Astronomical Sky” symposium, participants rightly moaned about the loss of dark skies around the globe. One paper reported that inefficient lighting costs the city of Vienna $720,000 annually; London $2.9 million; Washington, DC, $4.2 million; and New York City $13.6 million (Sullivan and Cohen 1999, pp. 363–68). Note that London, with a population similar to that of New York City, is more efficient in its inefficiency by nearly a factor of 5.

The astrophysicist’s quandary is not that light escapes into space but that the lower atmosphere supports a mixture of water vapor, dust, and pollutants that bounce some of the upward-flowing photons back down to Earth, leaving the sky aglow with the signature of a city’s nightlife. As cities become brighter and brighter, dim objects in the cosmos become less and less visible, severing urban dwellers’ access to the universe.

It’s hard to exaggerate the magnitude of this effect. A penlight’s beam, aimed at a wall across a darkened dining room, is easy to spot. But gradually brighten the overhead light, and watch how the beam gets harder and harder to see. Under light-polluted skies, fuzzy objects such as comets, nebulae, and galaxies become difficult or impossible to detect. I have never in my life seen the Milky Way galaxy from within the limits of New York City, and I was born and raised here. If you observe the night sky from light-drenched Times Square, you might see a dozen or so stars, compared with the thousands that were visible from the same spot when Peter Stuyvesant was hobbling around town. No wonder ancient peoples shared a culture of sky lore, whereas modern peoples, who know nothing of the night sky, instead share a culture of evening TV.

The expansion of electrically lit cities during the twentieth century created a technology fog that forced astronomers to move their hilltop observatories from the outskirts of towns to remote places such as the Canary Islands, the Chilean Andes, and Hawaii’s Mauna Kea. One notable exception is Kitt Peak National Observatory in Arizona. Instead of running away from the spreading and brightening city of Tucson, 50 miles away, the astronomers stayed and fought. The battle is easier won than you might think; all you have to do is convince people that their choice of outdoor lighting is a waste of money. In the end, the city gets efficient streetlamps and the astronomers get a dark sky. Ordinance No. 8210 of the Tucson/Pima County Outdoor Lighting Code reads as though the mayor, the chief of police, and the prison warden were all astronomers at the time the code was passed. Section 1 identifies the intent of the ordinance:

The purpose of this Code is to provide standards for outdoor lighting so that its use does not unreasonably interfere with astronomical observations. It is the intent of this Code to encourage, through the regulation of the types, kinds, construction, installation, and uses of outdoor electrically powered illuminating devices, lighting practices and systems to conserve energy without decreasing safety, utility, security, and productivity while enhancing nighttime enjoyment of property within the jurisdiction.

 

And after 13 other sections that give strict rules and regulations governing citizens’ choice of outdoor lighting, we get to the best part, section 15:

It shall be a civil infraction for any person to violate any of the provisions of this Code. Each and every day during which the violation continues shall constitute a separate offense.

 

As you can see, by shining light on an astronomer’s telescope you can turn a peace-loving citizen into a Rambo. Think I’m joking? The International Dark-Sky Association (IDA) is an organization that fights upward-pointing light anywhere in the world. With an opening phrase reminiscent of the one painted on Los Angeles Police Department squad cars, the IDA’s motto says it all: “To preserve and protect the nighttime environment and our heritage of dark skies through quality outdoor lighting.” And, like the police, the IDA will come after you if you transgress.

I know. They came after me. Not a week after the Rose Center for Earth and Space first opened its doors to the public, I received a letter from the IDA’s executive director, scolding me for the upward-pointing lights embedded in the pavement of our entrance plaza. We were justly accused—the plaza does have forty (very low wattage) lamps that help delineate and illuminate the Rose Center’s granite-clad arched entryway. These lights are partly functional and partly decorative. The point of the letter was not to blame the bad viewing conditions across all of New York City on these itty-bitty lamps but to hold the Hayden Planetarium accountable for setting a good example for the rest of the world. I am embarrassed to say that the lights remain.

But all that’s bad is not artificial. A full Moon is bright enough to reduce the number of stars visible to the unaided eye from thousands to hundreds. Indeed, the full Moon is more than 100,000 times brighter than the brightest nighttime stars. And the physics of reflection angles endows the full Moon with more than ten times the brightness of a half Moon. This moonglow also greatly reduces the number of meteors visible during a meteor shower (though clouds would be worse), no matter where you are on Earth. So never wish a full Moon upon an astronomer who is headed off to a big telescope. True, the Moon’s tidal force created tide pools and other dynamic habitats that contributed to the transition from marine to terrestrial life and ultimately made it possible for humans to thrive. Apart from this detail, most observational astronomers, especially cosmologists, would be happy if the Moon had never existed.

A few years ago I got a phone call from a marketing executive who wanted to light up the Moon with the logo of her company. She wanted to know how she might proceed. After slamming down the phone, I called her back and politely explained why it was a bad idea. Other corporate executives have asked me how to put into orbit mile-wide luminous banners with catchy slogans written across them, much like the skywriting or flag-dragging airplanes you see at sports events or over the ocean from a crowded beach. I always threaten to send the light police after them.

Modern life’s insidious link with light pollution extends to other parts of the electromagnetic spectrum. Next at risk is the astronomer’s radio-wave window to the cosmos, including microwaves. In modern times we are awash in the signals of such radio wave–emitting devices as cellular telephones, garage-door openers, keys that trigger “boip” sounds as they remotely lock and unlock car doors, microwave relay stations, radio and television transmitters, walkie-talkies, police radar guns, Global Positioning Systems, and satellite communications networks. Earth’s radio-wave window to the universe lies cloaked in this technologically induced fog. And the few clear bands that remain within the radio spectrum are getting progressively narrower as the trappings of high-tech living grab more and more radio-wave real estate. The detection and study of extremely faint celestial objects is being compromised as never before.

In the past half-century radio astronomers discovered remarkable things, including pulsars, quasars, molecules in space, and the cosmic microwave background, the first evidence in support of the big bang itself. But even a wireless conversation can drown such faint radio signals: modern radio telescopes are so sensitive that a cell-phone encounter between two astronauts on the Moon would be one of the brightest sources in the radio sky. And if Martians used cell phones, our most powerful radio telescopes would easily nab them, too.

The Federal Communications Commission is not unmindful of the heavy, often conflicting demands that various segments of society place on the radio spectrum. The FCC’s Spectrum Policy Task Force intends to review the policies that govern use of the electromagnetic spectrum, with the goal of improving efficiency and flexibility. FCC chairman Michael K. Powell told the
Washington Post
(June 19, 2002) that he wanted the FCC’s philosophy to shift from a “command and control” approach to a “market-oriented” one. The commission will also review how it allocates and assigns bands of the radio spectrum, as well as how one allocation may interfere with another.

For its part, the American Astronomical Society, the professional organization of the nation’s astrophysicists, has called on its members to be as vigilant as the IDA folks—a posture I endorse—in trying to convince policy makers that specially identified radio frequencies should be left clear for astronomers’ use. To borrow vocabulary and concepts from the irrepressible Green movement, these bands should be considered a kind of “electromagnetic wilderness” or “electromagnetic national park.” To eliminate interference, the geographic areas surrounding the protected observatories should also be kept clear of human-generated radio signals of any kind.

The most challenging problem may be that the farther an object is from the Milky Way, the longer the wavelength and the lower the frequency of its radio signals. This phenomenon, which is a cosmological Doppler effect, is the principal signature of our expanding universe. So it’s not really possible to isolate a single range of “astro” frequencies and assert that the entire cosmos, from nearby galaxies to the edge of the observable universe, can be served through this window. The struggle continues.

Today, the best place to build telescopes for exploring all parts of the electromagnetic spectrum is the Moon. But not on the side that faces Earth. Putting them there might be worse than looking out from Earth’s surface. When viewed from the Moon’s near side, Earth looks thirteen times bigger, and shines some fifty times brighter, than the Moon does when viewed from Earth. And Earth never sets. As you might suspect, civilization’s chattering communication signals also make Earth the brightest object in the radio-wave sky. The astronomer’s heaven is, instead, the Moon’s far side, where Earth never rises, remaining forever buried below the horizon.

Without a view of Earth, telescopes built on the Moon could point in any skyward direction, without the risk of contamination from Earth’s electromagnetic emanations. Not only that, night on the Moon lasts nearly 15 Earth days, which would enable astronomers to monitor objects in the sky for days on end, much longer than they can from Earth. And because there is no lunar atmosphere, observations conducted from the Moon’s surface would be as good as observations of the cosmos from Earth orbit. The
Hubble Space Telescope
would lose the bragging rights it now enjoys.

Furthermore, without an atmosphere to scatter sunlight, the Moon’s daytime sky is almost as dark as its night, so everybody’s favorite stars hover visibly in the sky, right alongside the disk of the Sun. A more pollution-free place has yet to be found.

On second thought, I retract my earlier callous remarks about the Moon. Maybe our neighbor in space will one day become the astronomer’s best friend after all.