A new exhibit on Albert Einstein dissects his slippery science
Science exhibits don't often come with a warning sign. But there's one at the entrance to a sprawling, new exhibit on Albert Einstein's life and science at the American Museum of Natural History in New York City. The sign has no words. It's a video screen whose center is dominated by a dark blob. Around the blob yawn strangely bloated, bowed, stretched, and sometimes doubled images of museum visitors. That's how they might appear if light from them were distorted by a black hole an unimaginably dense package of matter whose existence follows from Einstein's theories (SN: 9/29/01, p. 203: Available to subscribers at http://www.sciencenews.org/20010929/note10.asp).
What's the message of this cryptic warning? Astrophysicist Michael M. Shara, curator of the exhibit, translates it this way: "From the minute you step through the front door, we will twist your view of space and time and what your entire vision of the universe is like."
The exhibit delivers just that. Using computer simulations of warped space, time-manipulating soundscapes, and sparkling light sculptures, the displays immerse visitors in Einstein's counterintuitive science. In the exhibit's quieter, less flashy galleries, Einstein himself is minutely scrutinized. With artifacts, film footage, handwritten letters, and other documents, the exhibit probes Einstein's often-tumultuous life his friendships, loves, and political pursuits. The museum bills the new displays as "the most comprehensive exhibition ever on the life and theories of one of the greatest scientists of all time."
Follow the light
Albert Einstein is best known for a handful of monumental achievements. They include his iconic equation, E = mc2, which led ultimately to nuclear weapons, nuclear power, and enhanced understanding of the sun and other stars. Perhaps even more famous are his theories of relativity, which radically changed notions of time, space, and gravity.
Although most people are aware that Einstein fomented a revolution in physics, few are acquainted with the specific ideas behind that upheaval, notes physics educator Gretchen Walker, who helped coordinate the exhibit for the museum. In the new exhibit, about half the display space is devoted to conveying the gist of Einstein's most renowned revelations about light, time, energy, and gravity.
"It's the first attempt to explain the essence of Einstein's scientific contribution in a museum exhibition," says physicist Hanoch Gutfreund of the Hebrew University in Jerusalem at the recent launch of the exhibit.
The starting point for those explanations is the nature of light. Is it just a wave as most turn-of-the-century physicists had viewed it or also a stream of particles as Einstein ultimately concluded? If it's a wave, then what medium does it undulate through? Is it like an ocean wave advancing through the water?
Einstein already had begun pondering such questions as a teenager in the 1890s. The exhibit includes a sheet from a six-page handwritten letter billed as Einstein's first scientific paper which the 16-year-old boy mailed to his uncle. In it, the budding theorist imagines what it would be like to ride on a light wave.
Scientists at that time considered light to be moving ripples in a tenuous, uniform medium, called the aether. They presumed that the aether filled all of space. To test for its presence, scientists observed light beams propagating simultaneously in perpendicular directions and looked for a speed difference. The idea was this: Because Earth plows through the aether as it traces its orbit, light should appear to move slowest along the direction in which the planet pushes into the aether, quickest along the opposite direction, and at intermediate speeds along other directions. Yet the experiments detected no deviation in light's speed, regardless of direction.
This result deeply disturbed most physicists of the day.
Einstein took the findings at face value, rejected the idea that light travels through an aether, and went on to explore other logical consequences of light's apparently constant speed. One deduction is that nothing can move faster than light.
His cogitations eventually led him to develop the so-called special theory of relativity, which he first published in 1905. The theory's name connotes that it is limited to bodies that are moving at a constant speed rather than extending to objects in any type of motion. In his theory of relativity, Einstein deduced that time and space themselves must fluctuate. "He accepted a nonsensical universe," says Shara. With simple animations, the exhibit demonstrates how Einstein came to that view.
Numerous recent experiments, such as comparisons of clocks aboard planes and on the ground, have demonstrated that moving clocks tick more slowly than stationary ones. Einstein reached this conclusion theoretically from the premise that the speed of light is constant. The exhibit illustrates this logic. Adding eerie ambiance to those time-dilation displays, a staccato soundtrack of ticking clocks some speeding up, others slowing down plays in the background.
"It's a wonderful exhibit," comments Princeton University astrophysicist J. Richard Gott III, author of Time Travel and Einstein's Universe (2001, Houghton Mifflin). Says Gott: "They picked out a key item moving clocks tick slowly and explained it three different ways." If one explanation doesn't get through to a museum visitor, he notes, then another probably will.
On display also are six original sheets neatly hand-written by Einstein in German from a 72-page, 1912 manuscript on special relativity. Einstein's relativity investigations included calculations describing what happens to a body when it emits light. The results revealed that mass (m) would be transformed into energy (E) by a conversion factor, the speed of light (c) squared. One of the displayed pages includes the earliest remaining inscription by Einstein of E = mc2.
To calculate just how subtly or dramatically time will slow down for a given moving object, it's critical to know how fast the object is moving. To illustrate that aspect of time dilation, a wall-sized bank of digital clocks in the exhibit invites the visitor to suppose that Einstein had boarded a space ship on the day of his birth March 14, 1879 and zoomed off at various speeds.
For a half-dozen speeds ranging from that of today's spaceships essentially 0 percent of light speed to 99.99999999 percent of light speed, the clocks indicate today's date as it would be for the space-faring Einstein. For example, in the slowest ship, Einstein would have aged 123 years, right along with his friends and family on Earth. At the fastest speed, however, nearly 20 hours of Earth time would have elapsed for each second that would have ticked by for Einstein. That means that the baby Einstein who rocketed away on the day he was born would now be only 1 day old.
Having found a cosmic speed limit the speed of light, which is almost 300,000 kilometers per second Einstein also exposed a profound flaw in the theory of gravity handed down by Isaac Newton centuries before. Newton had proposed that the force of gravity acts instantaneously to attract two distant masses to each other. Einstein realized that this couldn't be. His cosmic speed limit required that nothing, including gravity, could act instantaneously over a distance.
Developing an alternative explanation for gravity took Einstein a decade. He published that alternative, the general theory of relativity, in 1915. The exhibit includes original pages of a hand-written draft of that seminal report, which extends the unexpected consequences of motion to accelerating objects.
Ultimately, Einstein showed that gravity's effects result not from instantaneous action across distances but from a warping of space-time itself. The sun's mass, for instance, distorts space-time in its own vicinity. That warping confines Earth and other planets to their elliptical orbits.
Even people's puny bodies bend space and time, albeit to a negligible degree. To give exhibit visitors a feel for this usually unperceived fact of their lives, a computer instantaneously calculates and amplifies their bodies' gravitation effects on surrounding space. As people approach a wall-sized monitor, it shows richly colored swells and dips in space-time. The biggest people and those closest to the wall trigger the most elaborate images. The display gives weight-consciousness a whole new meaning.
Einstein's revolution remains a work in progress. In many ways, researchers continue to explore, exploit, and test Einstein's theories. Today's physicists are observing black holes in deep space (SN: 11/09/02, p. 299: Available to subscribers at http://www.sciencenews.org/20021109/bob9.asp), tuning in to hypothetical ripples in space-time known as gravitational waves (SN: 5/6/00, p. 303: Available to subscribers at http://www.sciencenews.org/20000506/note17.asp), and fielding ultrasensitive space-time experiments, such as those on the upcoming Gravity Probe B satellite (SN: 11/15/97, p. 308).
Curiously, all these pursuits stem from work Einstein had done before 1920. Although he continued to work diligently in physics until his death in 1955 at the age of 76, he produced no further landmark theories.
That's partly because Einstein was caught up during his later decades fighting a futile, rear-guard action against quantum physics, whose laws govern the realm of the very small. In particular, he objected to the randomness in particle behavior that the new approach predicted. Quantum physics proved to be, like relativity theory, a great 20th-century revolution in modern physics, but it left Einstein behind.
Ironically, Einstein initially helped build the foundations of quantum physics. Indeed, he won the 1921 Nobel Prize in Physics for a 1905 advance in which he established a theoretical grounding for the particle-like aspect of light. The exhibit includes the medal and certificate that he received with that award.
Also, by continuing to be an astute skeptic, Einstein prodded quantum physics' developers to improve their theory.
In the latter part of his life, Einstein was also preoccupied with another theoretical quest. Having already clarified the nature of electromagnetism and reformulated gravity, the aging Einstein sought to unite those two phenomena within a single, comprehensive theory.
At the time, "many physicists thought it was a fool's errand," notes Shara. Yet today many top theorists are striving to develop similarly overarching theories, such as string theory (SN: 9/22/01, p. 184: http://www.sciencenews.org/20010922/bob9.asp). Their goal is to create a single theoretical framework that accounts for all the fundamental forces and particles in nature.
Rather than considering the last 30 years of Einstein's life a waste, Columbia University string theorist Brian R. Greene says that the period "was really what launched the current generation of work in the physical sciences." In one of the exhibit's galleries, Greene and other scientists discuss Einstein's scientific legacy in continuously running video clips.
Einstein never stopped his search for a unified theory. The day before his death on April 18, 1955, from a ruptured aortic aneurysm, Einstein asked his secretary to bring to the hospital a pad of paper on which he had been working. That very sheaf of papers, which Einstein smothered with calculations, serves as send-off as visitors leave the exhibit.
The Human Equation
Taking a comprehensive look at Einstein, the man
Besides being a great scientist, Albert Einstein was a father of the atomic age, a passionate defender of civil liberties, an ardent pacifist, and a champion of Jewish causes. Many papers, photos, films, and other artifacts that illustrate his multiple facets are on display in the new exhibit at the American Museum of Natural History in New York.
Included is his final high school report card, which dispels the myth that Einstein was a poor student. In fact, he received good-to-excellent grades in all subjects, and the highest possible marks all 6s in math and physics.
A letter from Einstein side-by-side with a response from Franklin Delano Roosevelt Jr. illuminates Einstein's role in prompting the United States to develop the first atomic bombs. In those letters, Einstein encourages research into such weapons, and President Roosevelt confirms that he has set in motion the machinery to pursue that goal.
Other memorabilia depict Einstein promoting socialism, fighting against Sen. Joseph McCarthy's anti-Communist witch-hunt of the early 1950s, and supporting the fledgling State of Israel.
From the collected mementos, a seamy side of Einstein also emerges. In a letter, Einstein flirts with one of the many women with whom he a married man had romantic affairs.
"We don't want to whitewash him," says exhibit curator Michael M. Shara. "Some of his family relationships were rocky, to say the least."
The Einstein exhibit, organized by the museum, the Hebrew University of Jerusalem, and the Skirball Cultural Center in Los Angeles, runs in New York until Aug. 10, 2003. It's scheduled to travel to Los Angeles in 2004 and Jerusalem in 2005.
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