Closer to The Skeleton of The Universe

Distribution of carbon monoxide across the sky

The Planck mission of the European Space Agency (ESA) has revealed that our galaxy contains islands of cold gas ever discovered, and a mysterious haze of microwaves. The finding will help reveal the skeleton of the cosmic structure, the “shot” on which it stands all we know. The new results obtained by the probe are discussed this week by astronomers around the world at an international conference in Bologna, Italy.

Planck results include the first CO map covering the whole sky. Carbon monoxide is a component of cold clouds that populate the Milky Way and other galaxies. Predominantly composed of hydrogen molecules, these clouds provide the deposits of which stars are born.

However, the hydrogen molecules are difficult to detect because they do not emit easily. Carbon monoxide is formed under similar conditions and, although much rarer, more easily emits light and therefore more detectable. So, astronomers used to trace hydrogen clouds.

“Planck is an excellent carbon monoxide detector in the whole sky,” says Jonathan Aumont, Institute of Space Astrophysics, University of Paris XI, Orsay (France). The search for carbon monoxide carried out with radio telescopes on earth consumes a lot of time, since they are limited to portions of the sky where molecular clouds are known or expected to exist. “The big advantage is that Planck scans the entire sky, enabling us to detect concentrations of molecular gas in places we expected to find,” says Aumont.

Planck has also detected a mysterious fog of microwaves that currently defies explanation. It comes from the region around the galactic center and is seen as a form of energy called synchrotron emission. This occurs when electrons pass through magnetic fields, having been accelerated by supernova explosions.

Getting to the Big Bang

The funny thing is that the synchrotron emission associated with galactic haze has different characteristics to the same issues seen in other parts of the Milky Way. Several explanations have been proposed for this unusual behavior, including higher rates of supernovae, galactic winds and even the annihilation of dark matter particles. So far, none have been confirmed and remains an enigma.

The main objective of Planck is to observe the Cosmic Microwave Background (CMB), relic radiation from the Big Bang, and measure their encoded information on the components of the universe and the origin of cosmic structure. But that is something that can only be accessed once all emission sources in the foreground, as the fog signals galactic carbon monoxide, have been identified and eliminated. The first database cosmological Planck is expected in 2013.