The Brilliant “Blunder” That Led to a Nobel Prize

By Amir Aczel | October 6, 2011 2:17 am

In 1917, a year after his general theory of relativity was published, Einstein tried to extend his field equation of gravitation to the universe as a whole. The universe as known at the time was simply our galaxy—the neighboring Andromeda, visible to the naked eye from very dark locations, was thought to be a nebula within our own Milky Way home. Einstein’s equation told him that the universe was expanding, but astronomers assured him otherwise (even today, no expansion is evident within the 2-million-light-year range to Andromeda; in fact, that galaxy is moving toward us). So Einstein inserted into his equation a constant now known as “lambda,” for the Greek letter that denoted it. Lambda, also called “the cosmological constant,” supplied a kind of force to hold the universe from expanding and keep it stable within its range. Then in 1929, Hubble, Humason, and Slipher made their monumental discovery using the 100-inch Mount Wilson telescope in California of very distant galaxies and the fact that they were receding from us—implying that the universe was indeed expanding, just as Einstein’s original equation had indicated! When Einstein visited California some time later, Hubble showed him his findings and Einstein famously exclaimed “Then away with the cosmological constant!” and never mentioned it again, considering lambda his greatest “blunder”—it had, after all, prevented him from theoretically predicting the expansion of the universe.

Fast forward six decades to the 1990s. Saul Perlmutter, a young astrophysicist at the Lawrence Berkeley Laboratory in California had a brilliant idea. He knew that Hubble’s results were derived using the Doppler shift in light. Light from a galaxy that is receding from us is shifted to the red end of the visible spectrum, while a galaxy that is approaching us has its light shifted to the blue end of the spectrum, from our vantage point. The degree of the shift is measured by a quantity astronomers call Z, which is then used to determines a galaxy’s speed of recession away from us (when Z is positive and shift is to the red).

But Perlmutter knew much more than that. As an astrophysicist he had studied the light curves (the way the intensity of a light source changes through time) that characterize immensely powerful celestial explosions called a Type Ia supernova. This kind of explosion is so powerful—six times more so than the more common Type II supernova, such as the one that created the Crab Nebula–that its light can be as intense as that of an entire galaxy. This allowed him to detect such mammoth, yet rare explosions in very faraway galaxies. Using telescopes in Hawaii, Chile, the Canary Islands, and space, his research team took pictures of hundreds of distant galaxies at a time, repeating the process at intervals of three weeks. In an entire galaxy, a Type Ia supernova will occur only roughly once a century—but once such an explosion is captured, it yields extremely important information. Since the light curve of such a supernova is the same, regardless of where it takes place, the intensity of the light from the explosion can be used as a “standard candle” for measuring the distance to the galaxy in which it takes place (in the same way that the size of the flame of a candle could be used to estimate how far a candle is from the observer since all candle flames are essentially of the same size). Thus Perlmutter’s team, the Supernova Cosmology Project at Berkeley, was able to establish for each galaxy in which they were fortunate to observe a Type Ia supernova, both a distance estimate (through analysis of the light curve), and a speed of recession (from the redshift, Z). An analysis of the data revealed a stunningly unexpected result: the universe is accelerating its expansion! The reason no one had expected such a finding was that the widely held assumption in cosmology had been that the mutual gravitational attraction among galaxies would eventually win out against the expansion, slow it down to a stop, and lead to a re-collapse of the universe on itself (and then perhaps a new big bang, a rebirth)—similarly to how a stone thrown up in the air will slow down, stop, and fall back to Earth.

The study’s result led to a major rethinking in cosmology, and it was then that physicists rediscovered Einstein’s lambda. In the same way that the cosmological constant had originally been used to hold down a universe that wants to expand, the same mathematical device, lambda—acting in the opposite way—can now be used to accelerate the universal expansion. The cosmological constant, Einstein’s “blunder,” was back with a vengeance! The energy that is believed to cause the accelerated expansion is called “dark energy,” and also “quintessence.” Dark energy is now believed to comprise as much as 73% of the entire mass-energy of the universe. What it actually is, nobody knows; mathematically, its action is performed by Einstein’s old lambda term.

“Imagine a lattice in three dimensions,” Saul Perlmutter told me when I interviewed him about his groundbreaking work completed in 1998, “At each corner of the lattice there is a galaxy. Now imagine that the lattice itself is growing in size—the distances from our corner, our galaxy, to all other corners of the lattice keep increasing.” These distances increase at a rate that is increasing all the time. Eventually, therefore, the universe will likely become very large and very diffuse—something that no one had expected. There will probably never be a recollapse and a rebirth. Our present universe seems to be a one-time event.

Saul Perlmutter shared this year’s Nobel Prize in physics for his discovery with Brian P. Schmidt of the Australian National University and Adam G. Riess of Johns Hopkins University and the Space Telescope Science Institute, who headed a competing research team, the High-Z Supernova Search, which obtained similar results at the same time. Their research changed the way we view the universe.



Amir D. Aczel is a researcher at the Center for the Philosophy and History of Science at Boston University and the author of 18 books about mathematics and physics, as well as numerous research articles. He is a Guggenheim Fellow and a frequent commentator on science in the media. See more at his website or follow him on Twitter: @adaczel.

CATEGORIZED UNDER: Space & Physics, Top Posts
  • Igor Fodor

    I would disagree that Einstein’s “blunder” led to this year’s physics Nobel Prize. After all, we used successfully so far general realtivity theory for calculating gravitational collapse and black holes! However, accepted cosmological model says that the universe consists of 70% dark energy, 25% dark matter and only 5% “normal” matter.
    One of the authors of the article in „Science“ from 28th May 1999, this year’s Nobel prize winner Saul Perlmutter, wrote at that time: „The universe consists largely from the dark matter and dark energy, and we do not know, what either of the both is“.
    As it seems, in any case, it’s not so much the discovery as such, but much more the courage to admit, that actually we have no idea what dark matter & dark energy might be.

    Could it be that the standard model of cosmology doesn’t hold water? Didn’t this year’s Nobel prize sealed the end of the contemporary cosmology, or rather the end of the Big Bang? It confirmed that we may never find out, how the universe originated, since the accelerated expansion smeares all the tracks, see the article „The end of cosmology?“ from Lawrence Krauss & Robert Scherrer in „Scientific American“ from 25th Feb. 2008. And Bruce Dorminey wrote in „Scientific American“ from 30th Dec. 2010 an article „Reliance on indirect evidence fuels dark matter doubts“.

  • Steve

    We live on the skin of a planet whose gravity influences our rate of time. Researchers have demonstrated one of Einstein’s theories of relativity – that the further away from the Earths center of gravity you are, the faster time passes. Einstein was proven correct when two synchronized atomic clocks were placed on different floors of a tall building. After a year, the clock further from the Earth`s center of gravity gained time quicker. By moving about 10 feet to the top of the stairs, you would age sooner by just under a millionth of a second per year!
    …Also, we live here on Earth in a “changing” rate of time, due to moving bodies of mass around us. Along with lifting the oceans twice a day, our Sun & Moon, as they change distance from the observer, influence the rate of time (however small) for the reader sitting in his chair at his altitude on Earth. Now, let`s step-up this scenario to a scale of about 4.3 million to 1 …
    There is a newly discovered supermassive black hole at the center of our Milky Way galaxy called Sagitarius A*. All elliptical galaxies are considered to have one. It`s said to contain 4.3 million solar masses & influences all the stars orbiting it in our galaxy. A study in 2008 which linked radio telescopes in Hawaii, Arizona and California (Very Long Baseline Interferometry) measured the diameter of Sagittarius A* to be 27 million miles. For comparison, the radius of Earth’s orbit around the Sun is about 93 million miles.
    Our star, the Sun, is on the inner edge of one of the spiral-shaped concentrations of gas and dust called the Orion Arm of the Milky Way. Since there are no known perfectly round orbits in the universe, we are either falling into or receding away from the singularity at the center.
    I maintain that we, along with our sun are being flung out from the singularity along on the Orion Arm . Look at a picture of a spiral galaxy. It`s spiral -shaped for a reason. It`s because it`s inner core is spinning & throwing out two jets of stars & dust. Our distance to Sagitarious A* is CONSTANTLY lengthening, which in turn CONSTANTLY changes our rate of time and (from our perspective)everything outside our galaxy SEEMS to speed away from us faster & faster seeming to break Newtons First Law of Motion. I can believe all visible galaxies are essentially expanding away from each other, but accelerating faster & faster? …No way.
    I admit, my tiny primate brain may not be able to fathom the total mass of the visible universe & beyond, I mean, -that`s a hell of a lot of mass in motion- but to accept it as mysteriously accelerating faster & faster makes no sense. I would much rather expound a theory that we are not so much traveling IN a bubble of space/time, but rather wherever our location is in distance to bubbles of space/time around these five
    bodies gives us our rate of time:
    dM(Earth) + dM(Moon) + dM(Sun) + dM(SagittariusA*) + dM(Big Bang) = Rate Of Time for observer
    d = distance from mass to observer
    M = mass
    I added “The Big Bang” ( whatever that was… ) because space is getting less dense (another variable).
    The relationship of distance from the observer to these five space/time bubbles, sets the rate of time for the observer, which varies. But an observer would never know it…
    I believe Saul Perlmutter reported what his instruments sensed but failed to account for the observer`s constant change in distance to a supermassive object. This gave him the readings he had of such impossible & illogical accelerations of distant galaxies. Of course this huge singularity was unknown at the time. I don`t ever expect anyone to find out what Dark Energy is now, because I think it was just convenient at the time to have a label for an unknown “Power”, which it wasn`t … just a slight miscalculation due to the nearness of an unknown supermassive body.
    -Steve Castleberry
    Santa Cruz, CA


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About Amir Aczel

Amir D. Aczel studied mathematics and physics at the University of California at Berkeley, where he was fortunate to meet quantum pioneer Werner Heisenberg. He also holds a Ph.D. in mathematical statistics. Aczel is a Guggenheim Fellow, a Sloan Foundation Fellow, and was a visiting scholar at Harvard in 2005-2007. He is the author of 18 critically acclaimed books on mathematics and science, several of which have been international bestsellers, including Fermat's Last Theorem, which was nominated for a Los Angeles Times Book Award in 1996 and translated into 31 languages. In his latest book, "Why Science Does Not Disprove God," Aczel takes issue with cosmologist Lawrence M. Krauss's theory that the universe emerged out of sheer "nothingness," countering the arguments using results from physics, cosmology, and the abstract mathematics of set theory.


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