Research Stories #2 - The importance of the Planck satellite

In the second of a new series of Research Stories we profile the work that is being done by one of our graduate students.

As one of Europe's foremost satellites nears the end of its useful life, PhD student Chris Crowe, who has been working on the project, explains how the team hopes the Planck mission will revolutionise our view of the universe.

Chris writes,

“The Planck satellite was launched in May 2009 from French Guiana, and travelled over one million miles from the earth to its resting point beyond the moon. Planck's instruments are cooled to a fraction of a degree above absolute zero (-273.15 Celsius), making it the coldest thing in space except laboratories on earth. Such low temperatures are necessary for the on-board detectors to study the Cosmic Microwave Background (CMB) radiation. The CMB is the first light released by the universe 380,000 years after the big bang, and forms an 'echo' of creation from when the universe was much smaller and hotter than it is now.

Planck has scanned the entire sky five times in the microwave regime, collecting data in multiple frequency bands which are now being analysed by teams around the world. On 14th January, the liquid helium coolant ran out, and the instrument then began to warm up, ending the data-collecting phase of the mission.

Planck's exquisite and unrivalled sensitivity and frequency coverage will allow us to distinguish between many competing cosmological theories, placing tight constraints on the composition and distribution of dark matter and the amount of dark energy in our universe. The data will also give us an insight into when and how the first stars in the universe formed, how galaxy clusters develop and indeed information about our own galaxy, the Milky Way.

High resolution images of swirling clouds of gas and dust show up as bright spots in the CMB temperature maps, and these give us information about how our own galaxy was formed, and how the gas and dust concentrations can give rise to solar systems like our own.

At Stephen Hawking's 70th birthday conference in Cambridge this January, many prominent cosmologists put forward competing theories of the dark matter composition of the universe.  Planck will be able to directly test these theories, making the next few months of data analysis a hugely exciting time for astrophysicists. 

A flurry of scientific papers will be released in 2013 detailing the main results from the mission, along with data catalogues containing information on galaxy clusters, gas and dust maps, galactic supernovae, and the pure CMB maps.  Does the universe have a beginning?  Could our universe be but one in an infinite string of expanding and collapsing worlds?  Clues to these types of problems could be encoded deep in the CMB radiation, making the next few years an exciting time to be a cosmologist.

Throughout my PhD I have analysed the effect that our own galaxy has on cosmological theories, by looking at how the gas and dust can modify the results that Planck should see. One of the most exciting results that could emerge from the data is the possibility of verifying cosmological inflation. Inflation is a theory developed in the 1980s that proposes an extremely rapid expansion of spacetime, where quantum fluctuations form the seeds for the large-scale structure we see today. To characterise accurately the dynamics of inflation one first has to remove all the contamination from our own galaxy, which is what my work has focussed on."

Chris helps run the public observing evenings at the Institute of Astronomy in Cambridge, every Wednesday at 7:15pm. Everyone is welcome to use the telescopes and look around the department, with free refreshments and a free public talk on an exciting area of astronomy. For more information, please see visit the Institute's website.

This is an archived news story, first posted in 2012.

For further information please contact the Fellow Communications Officer, Dr Tom Lambert (

News item posted Sunday, 3rd May 2015