cosmology

Ancient Light

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Seeing the Infancy of the Universe

A map of the sky at optical wavelengths shows a prominent horizontal band which is the light shining from our own Milky Way. The superimposed strip shows the area of the sky mapped by Planck during the First Light Survey. The color scale indicates the magnitude of the deviations of the temperature of the Cosmic Microwave Background from its average value, as measured by Planck at a frequency close to the peak of the CMB spectrum (red is hotter and blue is colder). The large red strips trace radio emission from the Milky Way, whereas the small bright spots high above the galactic plane correspond to emission from the Cosmic Microwave Background itself.
A map of the sky at optical wavelengths shows a prominent horizontal band which is the light shining from our own Milky Way. The superimposed strip shows the area of the sky mapped by Planck during the First Light Survey. The color scale indicates the magnitude of the deviations of the temperature of the Cosmic Microwave Background from its average value, as measured by Planck at a frequency close to the peak of the CMB spectrum (red is hotter and blue is colder). The large red strips trace radio emission from the Milky Way, whereas the small bright spots high above the galactic plane correspond to emission from the Cosmic Microwave Background itself. (Click to embiggen.)

The Planck Mission was lofted into orbit on the 14th of May this year to study light from the earliest ages of the universe.  Mission scientists have been doing routine testing and calibration of the satellites systems, and at the same time, monitoring the cooldown process for its detectors.

So, what’s Planck looking for? As with other missions that looked far back in time and space (such as COBE and WMAP) this one is searching out variations in the temperature of the Cosmic Microwave Background. To understand how important (and difficult that is), imagine trying to pick out the light of a firefly from across the solar system. Planck is trying to measure temperatures that are about a million times smaller than one degree. This is why the satellite’s detectors must be cooled to extremely low temperatures– close to absolute zero (–273.15°C, or zero Kelvin, 0K).

Now that the spacecraft is at its optimum operating condition, it’s starting to survey the sky, looking for those tiny, infinitesimal flickers of temperature change in the early cosmos — back before there were even stars or galaxies — when the cosmos was only 380, 000 years old. Understanding their data will bring astronomers closer to understanding the birth and evolution of the universe over the past 13.7 billion years.

The team released their early data this week, and the image above shows what theyr’e studying. Over the next 15 months, this European Space Agency microwave-sensitive satellite will concentrate on “first light” — the earliest flickers of light from a time when the universe was just beginning to form structures. Stay tuned!

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