Our first estimates of the age of the oldest stars in the Universe could be wrong, according to new data obtained from the European Space Agency's Planck satellite.
Research of a map of the Universe's cosmic microwave background, created using data from Planck, suggests that these stars are actually a little younger than we initially thought.
The cosmic microwave background is the first light the Universe ever saw. Estimates have it occurring around 380,000 years after the Big Bang over 13 billion years ago. It is now spread across the Universe, as shown in the map created from Planck's data.
The map shows that something called "reionization" happened later than originally thought. Basically, some time after the Big Bang, the Universe was dark and contained no starlight. Eventually, though, gravity brought pieces of matter together, which formed the first stars and galaxies. That, in turn, created radiation that ionized hydrogen in the Universe.
Originally, scientists thought that this reionization happened about 420 million years ago. However, computer simulations disputed that conditions with gravity were right at that time for star formation and that it must have occurred later.
Now, though, after carefully analyzing the Planck map, scientists estimate that this reionization happened 550 million years after the Big Bang, making the Universe's oldest stars 100 million years younger than we originally thought.
Next year, scientists will validate these measurements after analyzing data from other satellites and telescopes, which they believe will confirm this new estimate.
"According to Planck's observations, stars may be younger than believed, in bearing with other independent astrophysical indicators, and this finding may have major consequences on our attempts to understand the dark components of the Universe," says Carlo Baccigalupi, SISSA cosmologist. "Now we're awaiting data from the high-frequency instrument (HFI), whose maps are mostly constructed by the French team. These additional maps should provide confirmation and a clearer picture of the evidence we detected."
The Planck satellite launched in 2009 with a mission to observe the features of the Universe's cosmic microwave background. Although the ESA deactivated the satellite in 2013, scientists still study its data and maps, making new discoveries such as this one. It's even possible that Planck's data has evidence of gravitational waves somewhere within it, the elusive proof of the Universe's rapid expansion shortly after the Big Bang.
