Planck All-Sky Images Show Cold Gas and Strange Haze
The second all-sky image is the first map to show carbon monoxide over the whole sky. Cold clouds with forming stars are predominantly made of hydrogen molecules, difficult to detect because they do not readily emit radiation. Carbon monoxide forms under similar conditions, and though it is rarer, the gas emits more light. Astronomers can use carbon monoxide to identify the clouds of hydrogen where stars are born. Surveys of carbon monoxide undertaken with radio telescopes on the ground are time-consuming, so they are limited to portions of the sky where clouds of molecules are already known or expected to exist. Planck scans the whole sky, allowing astronomers to detect the gas where they weren't expecting to find it. Planck's primary goal is to observe the Cosmic Microwave Background, the relic radiation from the Big Bang, and to extract its encoded information about what our universe is made of, and the origin of its structure. This relic radiation can only be reached once all sources of foreground emission, such as the galactic haze and the carbon monoxide signals, have been identified and removed. "The lengthy and delicate task of foreground removal provides us with prime datasets that are shedding new light on hot topics in galactic and extragalactic astronomy alike," said Jan Tauber, Planck project scientist at the European Space Agency. Planck's first findings on the Big Bang's relic radiation are expected to be released in 2013. The new results are being presented this week at an international astronomy conference in Bologna, Italy.