ISRO Missions and Discoveries

[pib] What is Big Bang Nucleosynthesis (BBN)?


From UPSC perspective, the following things are important :

Prelims level: Big Bang Nucleosynthesis (BBN)

Mains level: BBN and its significance in the formation of our solar system

Indian researchers have discovered hundreds of Li-rich giant stars produced during BBN indicating that Li is being produced in the stars and accounts for its abundance in the interstellar medium.

Most of the space based theories and missions are focussed on the formation of our solar system. BBN is the most basic auxillary among them.

What is Big Bang Nucleosynthesis (BBN)?

  • BBN is the production of nuclei other than those of the lightest isotope of hydrogen during the early phases of the Universe.
  • Primordial nucleosynthesis is believed by most cosmologists to have taken place in the interval from roughly 10 seconds to 20 minutes after the Big Bang.
  • It is calculated to be responsible for the formation of most of the universe’s helium in various isotopic forms.
  • Essentially all of the elements that are heavier than lithium were created much later, by stellar nucleosynthesis in evolving and exploding stars.

Lithium in space

  • Lithium (Li), is one of the three primordial elements, apart from Hydrogen and Helium (He), produced in the Big Bang Nucleosynthesis (BBN).
  • However, the present measurement of Li in the interstellar medium and very young stars is about 4 times more than the primordial value.
  • Thus, identifying sources of Li enrichment in our Galaxy has been a great interest to researchers to validate BBN as well as a stellar mixing process.
  • In general, stars are considered as Li sinks. This means that the original Li, with which stars are born, only gets depleted over stars’ life-time as Li burns at relatively very low temperatures.

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