Scientists studying the Big Bang say that it is possible that string theory may one day be tested experimentally via measurements of the Big Bang’s afterglow.
Richard Easther, assistant professor of physics at Yale University will discuss the possibility at a meeting at Stanford University Wednesday, May 12, titled “Beyond Einstein: From the Big Bang to Black Holes.” Easther’s colleagues are Brian Greene of Columbia University, William Kinney of the University at Buffalo, SUNY, Hiranya Peiris of Princeton University and Gary Shiu of the University of Wisconsin.
String theory attempts to unify the physics of the large (gravity) and the small (the atom). These are now described by two theories, general relativity and quantum theory, both of which are likely to be incomplete.
Critics have disdained string theory as a “philosophy” that cannot be tested. However, the results of Easther and his colleagues suggest that observational evidence supporting string theory may be found in careful measurements of the Cosmic Microwave Background (CMB), the first light to emerge after the Big Bang.
“In the Big Bang, the most powerful event in the history of the Universe, we see the energies needed to reveal the subtle signs of string theory,” said Easther.
String theory reveals itself only over extreme small distances and at high energies. The Planck scale measures 10-35 meters, the theoretical shortest distance that can be defined. In comparison, a tiny hydrogen atom, 10-10 meters across, is ten trillion trillion times as wide. Similarly, the largest particle accelerators generate energies of 1015 electron volts by colliding sub-atomic particles. This energy level can reveal the physics of quantum theory, but is still roughly a trillion times lower than the energy required to test string theory.
Scientists say that the fundamental forces of the Universe – gravity (defined by general relativity), electromagnetism, “weak” radioactive forces and “strong” nuclear forces (all defined by quantum theory) – were united in the high-energy flash of the Big Bang, when all matter and energy was confined within a sub-atomic scale. Although the Big Bang occurred nearly 14 billion years ago, its afterglow, the CMB, still blankets the entire universe and contains a fossilized record of the first moments of time.
The Wilkinson Microwave Anisotropy Probe (WMAP) studies the CMB and detects subtle temperature differences, within this largely uniform radiation, glowing at only 2.73 degrees Celsius above absolute zero. The uniformity is evidence of “inflation,” a period when the expansion of the Universe accelerated rapidly, around 10-33 seconds after the Big Bang. During inflation, the Universe grew from an atomic scale to a cosmic scale, increasing its size a hundred trillion trillion times over. The energy field that drove inflation, like all quantum fields, contained fluctuations. These fluctuations, locked into the cosmic microwave background like waves on a frozen pond, may contain evidence for string theory.
Easther and his colleagues compare the rapid cosmic expansion that occurred just after the Big Bang to enlarging a photograph to reveal individual pixels. While physics at the Planck scale made a “ripple” 10-35 meters across, thanks to the expansion of the Universe the fluctuation might now span many light years.
Easther stressed it is a long shot that string theory might leave measurable effects on the microwave background by subtly changing the pattern of hot and cold spots. However, string theory is so hard to test experimentally that any chance is worth trying. Successors to WMAP, such as CMBPol and the European mission, Planck, will measure the CMB with unprecedented accuracy.
The modifications to the CMB arising from string theory could deviate from the standard prediction for the temperature differences in the cosmic microwave background by as much as 1%. However, finding a small deviation from a dominant theory is not without precedent. As an example, the measured orbit of Mercury differed from what was predicted by Isaac Newton’s law of gravity by around seventy miles per year. General relativity, Albert Einstein’s law of gravity, could account for the discrepancy caused by a subtle warp in spacetime from the Sun’s gravity speeding Mercury’s orbit.
More articles from Physics and Astronomy:
“Out of This World” Space Stethoscope Valuable on Earth, Too
22.05.2013 | Johns Hopkins
Storms on Uranus, Neptune Confined to Upper Atmosphere
21.05.2013 | University of Arizona
A fried breakfast food popular in Spain provided the inspiration for the development of doughnut-shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics and materials.
The doughnut-shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by a surrounding springy material made of polymers.
Droplets in this toroidal shape made ...
Frauhofer FEP will present a novel roll-to-roll manufacturing process for high-barriers and functional films for flexible displays at the SID DisplayWeek 2013 in Vancouver – the International showcase for the Display Industry.
Displays that are flexible and paper thin at the same time?! What might still seem like science fiction will be a major topic at the SID Display Week 2013 that currently takes place in Vancouver in Canada.
High manufacturing cost and a short lifetime are still a major obstacle on ...
University of Würzburg physicists have succeeded in creating a new type of laser.
Its operation principle is completely different from conventional devices, which opens up the possibility of a significantly reduced energy input requirement. The researchers report their work in the current issue of Nature.
It also emits light the waves of which are in phase with one another: the polariton laser, developed ...
Innsbruck physicists led by Rainer Blatt and Peter Zoller experimentally gained a deep insight into the nature of quantum mechanical phase transitions.
They are the first scientists that simulated the competition between two rival dynamical processes at a novel type of transition between two quantum mechanical orders. They have published the results of their work in the journal Nature Physics.
“When water boils, its molecules are released as vapor. We call this ...
Researchers have shown that, by using global positioning systems (GPS) to measure ground deformation caused by a large underwater earthquake, they can provide accurate warning of the resulting tsunami in just a few minutes after the earthquake onset.
For the devastating Japan 2011 event, the team reveals that the analysis of the GPS data and issue of a detailed tsunami alert would have taken no more than three minutes. The results are published on 17 May in Natural Hazards and Earth System Sciences, an open access journal of ...
22.05.2013 | Life Sciences
22.05.2013 | Ecology, The Environment and Conservation
22.05.2013 | Earth Sciences
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News