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Big Bang nucleosynthesis
In physical cosmology, Big Bang nucleosynthesis (or primordial nucleosynthesis) refers to the production of nuclei other than H-1, the normal, light hydrogen, during the early phases of the universe, shortly after the Big Bang. It is believed to be responsible for the formation of hydrogen (H-1 or simply H), its isotope deuterium (H-2 or D), the helium isotopes He-3 and He-4, and the lithium isotope Li-7. Big Bang nucleosynthesis begins about one minute after the Big Bang, when the universe has cooled enough to form stable protons and neutrons, after baryogenesis. From simple thermodynamical arguments, one can calculate the fraction of protons and neutrons based on the temperature at this point. This fraction is in favour of protons, because the higher mass of the neutron results in a spontaneous decay of neutrons to protons with a half-life of about 15 minutes.
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Space & Time News
January 29, 2026
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Jan. 8, 2026 A team of physicists has discovered a surprisingly simple way to build nuclear clocks using tiny amounts of rare thorium. By electroplating thorium onto steel, they achieved the same results as years of work with delicate crystals — but far more ...
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Jan. 2, 2026 A physicist has proposed a bold experiment that could allow gravitational waves to be manipulated using laser light. By transferring minute amounts of energy between light and gravity, the ...
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Jan. 27, 2026 Bright white rocks spotted by NASA’s Perseverance rover are rewriting what we thought we knew about ancient Mars. These aluminum-rich clays, called kaolinite, usually form on Earth only after ...
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Jan. 25, 2026 NASA is moving into a new phase of space exploration, with major progress across human spaceflight, science missions, and advanced technology. In just one year, the agency has launched multiple ...
Jan. 24, 2026 Falling space junk is becoming a real-world hazard, and scientists have found a clever new way to track it using instruments already listening to the Earth itself. By tapping into networks of ...
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