Exactly 100 years ago, 26-year-old physicist and mathematician Albert Einstein published three papers that changed scientists' \nperspectives forever. The year 2005 also marks 50th anniversary of the death of the German genius on April 18, 1955. Thinking back on his accomplishments and contributions, scientists all over the world have joined together celebrate the YEAR OF EINSTEIN.
Albert Einstein: big, poofy white hair, wild eyes and, well, a genius. \nEinstein is most celebrated for his work during his "miraculous year" of 1905, when at 26 he published three famed papers proving the existence of atoms and molecules, validating the field of quantum mechanics and developing the theory of relativity that led to the famous equation: E=mc². These ideas revolutionized modern physics forever. But his theory of a stable, unmoving universe -- his self-proclaimed "biggest mistake" -- never brought him anything but humiliation in the latter portion of his life. Now, 100 years since Einstein's famed publications and 50 years since his death, this forgotten theory could hold answers to a puzzling question. \nEinstein might have been wrong about being wrong.
The idea that failed\nShortly after publishing these papers, German-born Einstein introduced an idea called the "cosmological constant" response to error in the then-cosmological model he was trying to construct for a static, or stable, universe. The accepted theory of the time dictated that the universe wasn't expanding or getting smaller.\nWhen trying to construct his model of the universe, Einstein realized his general theory of relativity equations wouldn't hold. With his equations, a static universe would contract because of gravity. To address this problem, he created the cosmological constant, and the theory remained one of a static universe.\nThe "Big Bang," a widely accepted theory today, wasn't introduced until 1927.
The 'big bang'-up of Einstein's idea\nThe Big Bang theory states that between 10 and 20 billion years ago a cosmic explosion spread matter everywhere, thereby creating the universe. \nIn 1929, Edwin Hubble observed through his telescope that stars seemed to move outward after measuring their intensity and red shift, an increased wavelength of radiation emitted by a celestial object moving away from the observer, named for the fact that longer wavelengths of light are at the red end of the visible spectrum. His observations concluded that distant galaxies were moving farther away at great speeds, meaning the universe was expanding -- and directly contradicting Einstein's idea of a static universe. \nAnother piece of evidence also indicated that the Big Bang was a correct theory: microwave radiation background, or heat left over from the Big Bang, was observed. Some astronomers have tried to suggest another cause of this background, but none have been successful. With these observations, Einstein's view of the universe as static was refuted, and the cosmological constant was no longer needed. \nFor the brilliant physicist, the idea became an embarrassment and his "biggest mistake."
Was Einstein partially correct?\nIn the last decade or so, astrophysicists have looked at Einstein's "mistake" in a new light. There is evidence of a cosmological constant, but it might be what is actually accelerating the expansion of universe rather than keeping it static, astrophysicists believe. If this is true, then Einstein was half right: A cosmological constant exists, but it isn't keeping the universe stable. \nSomething is counteracting the pull of gravity at a greater magnitude than previously thought. The universe isn't just expanding; it's accelerating in its expansion, scientists have observed. The effects of the Big Bang are still overcoming the force of gravity, but something has accelerated the expansion. The explanation, as it is best known today, comes from exploring the nature of supernovas.\nSupernovas, massive stars in the late stages of their life that contract and then explode, are a different kind of light source and are measured on a larger scale. Because of the old age of a supernova, its distance away (called "r") will be diminished by 1/r². A measurement of light intensity can provide a measurement of distance. This enables scientists to create a more accurate picture of the universe and expand data past Hubble's observations. \nBecause light takes time to reach our telescopes from another part of the universe, "When you look out into the universe, you are looking back in time," said IU astrophysicist James Musser.\nSupernova experiments allow astrophysicists to see that the farther out in the universe, the faster objects are moving away from Earth. The reason behind this acceleration was needed -- and that's where Einstein's constant has arisen again.
Einstein's constant reborn\nAstrophysicists now are using Einstein's idea of a cosmological constant to explain the phenomenon of the accelerating expansion of the universe. But instead of using the constant as Einstein did to describe why the force of gravity isn't pulling the universe in on itself, astrophysicists are using it to describe why the universe increasingly is overcoming the force of gravity, thus accelerating its expansion.\nThe so-called cosmological constant is basically "energy contained in space itself" or the "spontaneous generation of energy at a low level," Musser said. When put to a different use, this constant is an attractive solution.\nMost astrophysicists accept the evidence that the universe's expansion is accelerating and that something big has to be creating such an effect. \n"People are speculating there doesn't have to be a cosmological constant," IU astrophysicist Constantine Deliyannis said, referring to physicists who disagree with this idea.\nAnother IU astrophysicist, Stuart Mufson, agrees. \n"We can see back to the time when the universe was decelerating, it turns off and on. Why (is the universe accelerating) now?" Mufson said.\nMusser believes in the next decade, all doubts about the existence of a cosmological constant will be removed.\n"The next set of experiments planned for the next decade to 15 years will put the last nail in the coffin. I expect that they will largely confirm that the universe is made mainly out of (the cosmological constant). Our matter is only a small fraction of the universe," Musser said. "Of course, there could always be surprises."\nEven physicists are starting to look at this new idea. \n"This is huge news. So many particle physicists have been migrating to astrophysics because they are so interested in it," said IU physicist Jon Urheim. "This dark energy might ultimately have some particle physics explanation. Right now there is no generally accepted explanation for it."
Still the man\nSo, even as the technology used for looking at the universe gets more efficient, detailed and ground-breaking, scientists are still talking of the extraordinary physicist who died 50 years ago -- a man who has been proven wrong about being wrong. At the very least, he was only half wrong about the cosmological constant he created. \n"(Einstein) would have been happy, I think -- there was no reason for it, and now there is," Musser said. "His theory of relativity and special relativity is the truth." \nThis year has been declared "The World Year of Physics" by the United Nations in honor of Einstein's "miraculous year." \nHis papers are still cited and remain an instrument that accelerates the learning of current and future physics students. He is still a superstar.\n-- Contact Staff Writer Rebecca Glasgow at reglasgo@indiana.edu.
