Thread by @esascience

From an almost perfect Universe to the best of both worlds: final data release of our @Planck mission confirms the standard model of cosmology... but with a few details to puzzle over ➡️ esa.int/Our_Activities…

Planck scanned the sky between 2009 and 2013 to observe the Cosmic Microwave Background, or #CMB, which is the most ancient light in the history of our Universe, emitted only 400,000 years after the Big Bang, and hidden beneath the microwave emission of our Milky Way galaxy

The first @Planck data release, in 2013, revealed the most precise image of the Cosmic Microwave Background ever obtained. Tiny fluctuations of the #CMB temperature in the sky allow scientists to investigate the contents, history & expansion of our #Universe in painstaking detail

The second data release, in 2015, contained additional information about the polarisation of the Cosmic Microwave Background, which carries an imprint of the last interaction between the #CMB and matter particles in the early #Universe, and so extra information about our cosmos

Today the @Planck Collaboration has made their final release, with newly processed data of Cosmic Microwave Background temperature & polarisation. Scientists have retrieved cosmological models based solely on temperature, solely on polarisation, and on both. And they all match 👍

The new data confirm that @Planck's earlier description of the #Universe as a place containing about 5% ordinary matter, 27% dark matter and 68% dark energy + populated by structures that had been seeded during an early phase of inflationary expansion, is largely correct

Of course, there are still some 'tensions' that need explaining. For example, the rate of expansion of the Universe – called the Hubble Constant – inferred from @Planck data doesn't match the value obtained from more 'local' observations. Could this be a hint of new physics? 🤔

This is the legacy of @Planck: with its almost perfect #Universe, the mission has given researchers confirmation of their models but with a few details to puzzle over. In other words: the best of both worlds #PlanckLegacy
Full story: esa.int/Our_Activities…