Added January 9, 2007, new link to Higher Moments added April 7,2007
The Cosmic Cartographer and Nobel Prize Winner:
MIT Technology Review January 2007
R. Rydin comments added in bold and italics
"George Smoot didn't set out to be a weather reporter or a mapmaker. But in 1992, he made cartographic history when he created the first map of the young universe by charting slight variations in the temperature of 14-billion year-old radiation. Variations in this 'cosmic microwave background,' or CMB, give astrophysicists clues about how complex structures like galaxies formed."
"A physics professor at the University of California, Berkeley, Smoot shares the 2006 Nobel Prize in physics with John Mather of NASA Goddard Space Flight Center for work on the CMB, whose existence supports the big bang theory." This is an assertion, because there is also ample evidence that the Big Bang model is incorrect.
"Discovered in the 1960s, the CMB had been predicted by the big bang theory. The radiation comes not from a place in the universe but from a time soon after the universe's formation. 'When we look back at the radiation, we're looking back to a time in the universe when everything was hot and dense like the plasma in our sun,' explains Edmund Bertschinger, head of the MIT physics department's astrophysics division. As the universe expanded, it cooled, and so did the CMB, which is now only about 2.7 degrees above absolute zero. 'We're seeing that afterglow in our radio telescopes billions of years later,' he says." It is not obvious that the CMB was predicted theoretically by General Relativity, but along with Hubble's Law in 1929, and Gamow's work on synthesizing helium from neutrons in 1946, the CMB did suggest but not prove that the Big Bang model had a hot beginning. Everything that followed is theoretical physics designed to explain how a hot singularity could have made the matter we see today, but there is no experimental proof that this scenario ever took place.
"The photons of the CMB provide something like a photograph of the universe about 370,000 years after the big bang, when it cooled to about 3,000 °C, releasing particles to form the first atoms. Until then, the universe was an opaque, high-energy plasma; photons were caught up in heated and intimate conversation with subatomic particles like electrons. When the universe cooled and atoms formed, photons-including those that make up the CMB-could for the first time move freely." Again, the when and how are theoretical assertions of a Big Bang scenario.
"When Smoot started working on the CMB, its exact spectrum was unknown, and it appeared to have completely uniform blackbody energy. This uniformity suggested an early universe where energy and matter were distributed homogeneously, a scenario apparently incompatible with today's varied and complex universe. How could stars grouped into galaxies grouped into clusters of galaxies surrounded by large voids emerge from an early universe where matter was spread out as smoothly as icing on a wedding cake? For the big bang theory to hold up, the early universe would have to have had lumps upon which quantum-mechanical forces and then gravity could act, eventually causing galaxies and other structures to form." A theoretical formulation requirement of Friedmann's mathematical solutions to General Relativity was an assumption that the beginning was homogeneous and isotropic, so the problem has always been to find a mechanism that made the resulting universe lumpy and bumpy, and quite inhomogeneous.
"In search of this lumpiness, many groups, including Smoot's, sent radiation detectors on balloons and even in spy planes to altitudes where the CMB is almost completely unfiltered by Earth's atmosphere. Meanwhile, others calculated what level of fluctuation in the energy of the early universe would have allowed lumps, or seeds, to form. Smoot joined a group, led by Mather at NASA, which was working to get a sensitive, radiation-detecting satellite called COBE (Cosmic Background Explorer) into orbit. By the time COBE was launched on November 18, 1989, astrophysicists had established that very tiny variations in the CMB-as small as a hundred-thousandth of a degree would indicate an early universe diverse enough to have produced the current one." The theoretical Big Bang calculations came up with extremely small fluctuations that could foster growth of galaxies, which was very fortunate because it was already obvious experimentally that the fluctuations weren't very big at all!
"Smoot was in charge of a group of six instruments on COBE, called differential microwave radiometers, that looked for temperature variations called anisotropy in the CMB. Up above Earth, the orbiting COBE had unobstructed reception of the CMB in all directions. Smoot and his Berkeley team analyzed a year's worth of these temperature measurements - millions, looking for anisotropy; when they seemed to find it, they worked to convince themselves that it wasn't due to noise from the instruments on COBE." In retrospect, accuracies of the order needed to make this data significant are almost impossible to obtain in any experiment!
"In 1992, Smoot announced that COBE had found hundred-thousandths of-a-degree variations in the energy of the CMB. His map of these variations, showing roughly which patches in the early universe were slightly warmer and which were slightly colder, has been called the universe's baby picture. 'The amazing thing is, the universe is almost completely uniform;' he says. 'It's more uniform than a billiard ball.' Smoot received his half of the Nobel Prize for his work on the map; Mather was honored for leading the COBE project and measuring the CMB's spectrum."
"Astrophysicists say Smoot and Mather's announcement of COBE's results was a turning point for cosmology, when philosophical speculation about the universe's origins gave way to a science built on quantitative evidence. Smoot's map was subsequently verified by further balloon experiments and has since been enhanced by more sensitive measurements from WMAP, a NASA satellite still in orbit." This is pretty weak data to justify changing the conclusion from speculation to quantitative evidence!
"In a universe thought to be 96 percent mysterious dark matter and dark energy, there are plenty of new and strange territories to explore. 'I have a list of eight questions I think are really important,' he says. One day, Smoot plans to start a cosmological-physics center to address them. But for now, they're bullet points in his lectures-and the cosmic mapmaker keeps the list tacked to his wall." All this dark matter and energy is needed to make the Big Bang model work, and could be interpreted as indicating failure of the model to match experimental reality!
Smoot's List: The eight cosmology questions that keep George Smoot up at night (and some comments on the answers to those questions).
1. Did inflation (the exponential expansion of the young universe) happen? How? This assumes that the Big Bang model is valid and began at a singularity, which then needs a faster than light speed expansion to get to a finite size that matches Hubble expansion.
2. What is dark matter? A better question is, does dark matter exist at all!
3. What is dark energy? A better question is, does dark energy exist at all!
4. Why is there more matter than antimatter in the universe? This is the only valid question in the set, which really asks whether or not baryon conservation is valid!
5. Are there other relics of the young universe to be found (e.g., cosmic strings?) Again, strings are mathematical artifacts of general relativity and the Big Bang, so they may not exist at all!
6. Are there more than four (three spatial dimensions and time) dimensions? This is the same question given above, which is an attempt to justify string theory.
7. Do fundamental constants vary? This is another attempt to fudge experimental data to get it to agree with the Big Bang model.
8. What other exotic forces might there be? Perhaps the question is whether or not the four forces we already accept are correct, or should the weak force be replaced with a quantum force that includes a quantum gravity term.