Ultracold Big Bang Experiment Simulates Evolution of Early Universe

Scientists created this detailed, all-sky picture of the infant universe from nine years of data from the orbiting Wilkinson Microwave Anisotropy Probe. 

The image reveals 13.77 billion year old temperature fluctuations—shown as color differences—that correspond to the seeds that grew to become the galaxies. 

Physicists now are using clouds of ultracold atoms in a vacuum chamber to simulate the growth of structure in the early universe. 

Credit: NASA/WMAP Science Team

Physicists have reproduced a pattern resembling the cosmic microwave background radiation in a laboratory simulation of the big bang, using ultracold cesium atoms in a vacuum chamber at the University of Chicago.

"This is the first time an experiment like this has simulated the evolution of structure in the early universe," said Cheng Chin, professor in physics.

Cheng Chin

Chin and his associates reported their feat in the Aug. 1 edition of Science Express, and it will appear soon in the print edition of Science.

Chin pursued the project with lead author Chen-Lung Hung, PhD'11, now at the California Institute of Technology, and Victor Gurarie of the University of Colorado, Boulder.

Their goal was to harness ultracold atoms for simulations of the big bang to better understand how structure evolved in the infant universe.

The cosmic microwave background is the echo of the big bang. Extensive measurements of the CMB have come from the orbiting Cosmic Background Explorer in the 1990s, and later by the Wilkinson Microwave Anisotropy Probe and various ground-based observatories, including the UChicago-led South Pole Telescope collaboration.

These tools have provided cosmologists with a snapshot of how the universe appeared approximately 380,000 years following the Big Bang, which marked the beginning of the universe.

It turns out that under certain conditions, a cloud of atoms chilled to a billionth of a degree above absolute zero (-459.67 degrees Fahrenheit) in a vacuum chamber displays phenomena similar to those that unfolded following the big bang, Hung said.

"At this ultracold temperature, atoms get excited collectively. They act as if they are sound waves in air," he said.

The dense package of matter and radiation that existed in the very early universe generated similar sound-wave excitations, as revealed by COBE, WMAP and the other experiments.

The synchronized generation of sound waves correlates with cosmologists' speculations about inflation in the early universe.

"Inflation set out the initial conditions for the early universe to create similar sound waves in the cosmic fluid formed by matter and radiation," Hung said.

Journal Reference:
C.-L. Hung, V. Gurarie, C. Chin. From Cosmology to Cold Atoms: Observation of Sakharov Oscillations in a Quenched Atomic Superfluid. Science, 2013; DOI: 10.1126/science.1237557

ESA Planck satellite: Maps detail Universe's ancient light

The map shows tiny deviations from the average background temperature, where blue is slightly cooler and red is slightly warmer. 

The cold spots are where matter was more concentrated and later collapsed under gravity to form stars and galaxies. 

Image: ESA/Planck Collaboration

A spectacular new map of the "oldest light" in the sky has just been released by the European Space Agency.

Scientists say its mottled pattern is an exquisite confirmation of our Big-Bang model for the origin and evolution of the Universe.
But there are features in the picture, they add, that are unexpected and will require ideas to be refined.

The map was assembled from 15 months' worth of data acquired by the 600m-euro (£515m) Planck space telescope.

It details what is known as the cosmic microwave background, or CMB - a faint glow of microwave radiation that pervades all of space.

Its precise configuration, visible in the new Planck data, is suggestive of a cosmos that is slightly older than previously thought - one that came into existence 13.82 billion years ago.

This is an increase of about 50 million years on earlier calculations.

The map's pattern also indicates a subtle adjustment is needed to the Universe's inventory of contents.

It seems there is slightly more matter out there (31.7%) and slightly less "dark energy" (68.3%), the mysterious component thought to be driving the cosmos apart at an accelerating rate.

Planck is the third western satellite to study the CMB. The two previous efforts - COBE and WMAP - were led by the US space agency (Nasa). The Soviets also had an experiment in space in the 1980s that they called Relikt-1.

• The CMB's temperature fluctuations are put through a number of statistical analyses
• Deviations can be studied as a function of their size on the sky - their angular scale
• When compared to best-fit Big Bang models, some anomalies are evident
• One shows the fluctuations on the biggest scales to be weaker than expected
• Theorists will need to adjust their ideas to account for these features

The CMB is the light that was finally allowed to spread out across space once the Universe had cooled sufficiently to permit the formation of hydrogen atoms - about 380,000 years into the life of the cosmos.

It still bathes the Earth in a near-uniform glow at microwave frequencies, and has a temperature profile that is just 2.7 degrees above absolute zero.

But it is possible to detect minute deviations in this signal, and these fluctuations - seen as mottling in the map - are understood to reflect the differences in the density of matter when the light parted company and set out on its journey all those years ago

The fluctuations can be thought of as the seeds for all the structure that later developed in the cosmos - all the stars and galaxies

Scientists subject the temperature deviations to a range of statistical analyses, which can then be matched against theoretical expectations.

This allows them to rule in some models to explain the origin and evolution of the cosmos, while ruling out a host of others.

The team that has done this for Planck's data says the map is an elegant fit for the standard model of cosmology - the idea that the Universe started in a hot, dense state in an incredibly small space, and then expanded and cooled.

At a fundamental level, it also supports an "add-on" to this Big Bang theory known as inflation, which postulates that in the very first moments of its existence the Universe opened up in an exponential manner - faster than light itself.

But because Planck's map is so much more detailed than anything previously obtained, it is also possible to see some anomalies in it.