Oldest Stars Lit Up Universe Later Than Thought

The oldest stars in the sky aren't so old after all. They actually lit up the Universe more than 100 million years later than scientists previously thought, according to a new study.

Data from the European Space Agency's (ESA) Planck space telescope originally suggested that the light from some of the very first stars and galaxies lit up the Universe 380,000 years after the Big Bang, ending a period known as the "Dark Ages."

However, new measurements - which studied the Cosmic Microwave Background (CMB), or the light left over from the Big Bang - indicate that this great illumination occurred about 550 million years after the Big Bang. This pushes back the age of the first stars about 100 million years later than Planck's previous estimate.

"While these 100 million years may seem negligible compared to the Universe's age of almost 14 billion years, they make a significant difference when it comes to the formation of the first stars," Marco Bersanelli of the University of Milan, a member of the Planck Collaboration, said in a statement.

The new assessment is based on the afterglow from the CMB, which amazingly can be seen even today covering the whole sky at microwave wavelengths. (Scroll to read on...)