First Planck results: the Universe is still weird and interesting

The cosmic microwave background—temperature fluctuations left over from 380,000 thousand years after the Big Bang. This new map is based on data from the Planck mission.

ESA/Planck Collaboration/D. Ducros

Our current model of cosmology—the origin and structure of the whole Universe—has survived another major test, with the release of the first 15 months of data from the Planck mission. Planck is a European Space Agency mission, designed to study the cosmic microwave background (CMB), which preserves information about the conditions that persisted immediately after the Big Bang.

Combined with results from prior experiments, Planck has revealed a Universe a little older than previously thought, and with a slightly different balance of ingredients. Although there were no major surprises, some of its data provided stronger hints about inflation, a popular model that explains why the modern Universe looks the way it does. Other measurements ruled out extra neutrinos, provided even stronger evidence for the existence (though not the identity) of dark matter, and indicated that there's a bit less dark energy than previous measurements had suggested.

But amid these incremental changes, there was a bit of a surprise: despite the best hopes of researchers, Planck data does not rule out the existence of anomalous temperature fluctuations at large scales. These may hint at either new physics that influenced the Universe's expansion, or previously unknown foreground sources that alter the CMB.