New study reveals that in the beginning of the Universe, first stars are 10,000 times the size of Sun.
More than 13 billion years ago, there is nothing than neutral gas. Mainly made up of hydrogen and helium.
After passing millions of years all neutral gases converted in to matter balls, this age is known as Cosmic Dark Age.
Neutral gas began to collect and clump together. Hydrogen and helium released a little bit of heat, which allowed clumps of the neutral gas to slowly reach higher densities.
High density clumps and hot. That means stars made from these clumps can become incredibly large.
First stars in the Universe, would have been incredibly bright and would have lived extremely short lives, less than million years.
After that, they would have died in furious bursts of supernova explosions, because of end of fuel. Today's stars lives for billions of years.
After the exlplosion, they carried the products of the internal fusion reactions, elements heavier than hydrogen and helium are used for next cycle of star formation.