Did the Big Bang really occur? What happened next? When did the first stars appear? What is the universe made of? The instruments onboard the Planck satellite will provide elements to help answer all of these questions. New analyses of measurements taken by Planck between 2009 and 2013 have just been revealed by the European Space Agency. Among them are several surprises, including the emergence of a new range of measurements in the study of the cosmos!
To understand the significance of this publication, the CNES invites you to participate in the next Space Tuesday (Mardi de l’Espace), Tuesday, February 17 at 7:30pm in Paris. Two Planck experts will be with us: Olivier La Marle, coordinator of astrophysics programs at the CNES, and François Bouchet, a member of the Institut d’astrophysique de Paris and one of the authors of the article presenting these new analyses.
Imagine being able to see a light emitted 13 billion years ago. Got it? Now imagine being able to extract information from it about the events that this light witnessed, at the moment of its creation and throughout its journey to us today. That is, in a simplified way, what Planck is able to do.
Map of the relic radiation of the universe: an idea of what the universe looked like when it was still very young. Fingerprints, of sorts, can be seen in this version, unveiled on February 5th. This is the polarization of the light.
This light that Planck is interested in is called relic radiation or the cosmic microwave background. “These are rays emitted just 380,000 years after the Big Bang. The sky today retains a trace of the scorching past of our universe, in the form of a very weak “relic” radiation. This radiation is invisible, since it is essentially in the infrared and millimetric range,” explains Olivier La Marle.
A new physical variable: polarization
The study of this relic radiation is one of the most complex and specialized fields of cosmology. That is due especially to the fact that the concepts involved are abstract for the human brain. And not only are the wavelengths observed by the satellite invisible to the naked eye, but the way it observes them is unprecedented, too! Planck does not settle for measuring the frequency or even the intensity of the light; it also measures the orientation. This is what we call polarization.
To simplify it to the max, this is a new measure (or physical variable) in the observation of light, a new way to read it, in a sense. What’s the interest of that? “It’s a brand new field of information that has just been added to what we could learn before,” explains François Bouchet. This information is particularly related to the very first phases of the evolution of the Universe. “In the Big Bang theory, there are specific patterns of polarization that we are looking for. Polarization could allow us to detect residual traces of primordial gravitational waves,” adds Olivier La Marle. Which is, incidentally, what an American research team believed it had discovered last year, thanks to the measurements of Bicep2.
Among the conclusions of the Planck scientists’ new analysis, there is, in particular, a reinterpretation of this much-talked-about announcement and even a new estimation of the age of the very first stars in the universe. Quite a lineup!
Come learn more about these new discoveries straight from the mouths of those who have worked on Planck. Join us Tuesday, February 17th at 7:30pm at the Café du Pont Neuf in Paris, or on Twitter via #CNESTweetup.