The team behind the European Space Agency’s Planck satellite has released their latest set of data stemming from observations of the Cosmic Microwave Background (CMB) between 2009 and 2013. What they’ve found strongly supports the prevailing view of how our universe began: the big bang. The CMB is the faint afterglow of that origin – energy released when the universe was around 380,000 years old and had expanded and cooled enough for light to stream outwards. As such it contains clues to what the universe was like in its earliest moments. This latest set of observations does not disagree with our picture of where our universe came from.
There are two other particularly interesting outcomes from this latest finding. The first is that the data are able to rule out certain models for dark matter – the invisible glue thought to bind galaxies together. In particular, it seems the model used to explain an excess of positrons found by a detector aboard the International Space Station has gone out the window. Perhaps that excess isn’t the result of dark matter after all; there had already been some serious doubts.
The second regards the claim earlier in the year by the team behind the BICEP2 detector that they had uncovered evidence of ‘twists’ in the light from the CMB which, it was said, were caused by the universe’s undergoing a period of rapid inflation in its earliest moments. Such inflation is key to get our big bang model to work. Some versions of inflation also necessarily require our universe to be one of many – part of an infinite multiverse. However, earlier in the year the Planck team poured cold water on the BICEP2 claims by suggesting the same signal could also have been caused by dust in our Milky Way galaxy. I had hoped that this data release from Planck would help clear up the mystery once and for all. I guess we’ll just have to wait a little longer.