Reference Terms
from Wikipedia, the free encyclopedia
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.
Related Stories
1
2
Space & Time News
September 28, 2026
Sep. 28, 2026 Spaceflight may dramatically change the gut within weeks, causing bacteria to break down more protein as food moves more slowly through the intestines. The shift could help explain astronaut constipation and may have wider effects on health, making ...
Sep. 25, 2026 Scientists think beneficial fungi could help transform nutrient-poor lunar and Martian regolith into a material capable of supporting crops. By helping plants access nutrients and withstand harsh conditions, these microbes could someday make ...
Sep. 22, 2026 An amateur astronomer searching satellite maps for a Quebec camping spot accidentally discovered a massive ancient impact crater. Scientists later found shatter cones that confirmed the ...
Sep. 21, 2026 NASA’s Roman Space Telescope has successfully activated its 300-megapixel infrared camera, which will capture enormous stretches of the cosmos with Hubble-like sharpness. Its planet-hunting coronagraph is also working as expected, putting Roman ...
Sep. 18, 2026 NASA’s Roman Space Telescope may now have enough fuel for at least 22 years of science, more than double its original 10 year design life. An extremely precise course correction, extra fuel at ...
Sep. 17, 2026 A pocket-sized, roughly $100 detector can reveal the invisible stream of cosmic particles constantly passing through Earth and even through our bodies. What began as a student physics project is now being used in major experiments, balloon missions, ...
Sep. 13, 2026 Scientists have engineered yeast to turn PET plastic and agricultural waste into ingredients for protein-rich, 3D-printed cookies called µBites. Developed partly for NASA’s Deep Space Food Challenge, the system can produce proteins, fats, ...
Sep. 2, 2026 Solar sails pushed by powerful lasers could reach incredible speeds, but relativity may eventually make the light itself work against them. At around 75% of the speed of light, scattered photons can begin creating drag, adding a surprising obstacle ...
Sep. 1, 2026 NASA has brought two of Swift’s telescopes back online after technical problems derailed a commercial mission intended to rescue the aging observatory by raising its orbit. With atmospheric drag pulling the spacecraft downward faster than ...
Aug. 31, 2026 NASA’s Roman Space Telescope has launched on a million mile journey to L2, where it will scan huge portions of the cosmos for clues about dark matter, dark energy, and distant worlds. With survey ...
Aug. 28, 2026 NASA’s Roman Space Telescope will combine Hubble-like detail with a field of view 100 times larger, giving astronomers a sweeping new way to explore the cosmos. Its observations could uncover hidden planets, map billions of cosmic objects, and ...
Aug. 26, 2026 NASA has successfully tested a system that allows satellites to navigate without GPS by using other spacecraft and debris as landmarks in orbit. In just three days, FALCON also improved the known orbits of more than 200 space objects completely ...
Latest Headlines
updated 12:56 pm ET
Sep. 28, 2026 JWST has revealed that young planetary systems lose their planet-building gas through a changing mix of powerful jets, molecular winds, and radiation-driven outflows. As the disks age and their gas ...
Sep. 27, 2026 Measurements of ancient light from the cosmic microwave background suggest that the universe is remarkably flat. But that does not prove it is infinite, because the observable cosmos could be only a ...
Sep. 26, 2026 Artemis II astronauts Victor Glover and Reid Wiseman are transitioning to emeritus status at NASA after their historic journey around the Moon ...
Sep. 24, 2026 A dead white dwarf with no detectable disk has somehow produced a powerful shock wave that appears to have persisted for at least 1,000 years. Its ...
Sep. 24, 2026 Ancient grains inside one of the oldest known meteorites reveal that a surprisingly strong magnetic field existed during the solar system’s first ...
Sep. 24, 2026 Ariel, one of Uranus’ moons, may once have contained a subsurface ocean more than 100 miles deep beneath its fractured icy shell. The finding, ...
Sep. 24, 2026 Hubble observations of massive stars in metal-poor dwarf galaxies are revealing clues to why the early universe looks so unusual. Researchers found that stellar winds weaken sharply at extremely low ...
Sep. 23, 2026 Astronomers have discovered the first globular cluster stellar stream beyond the Milky Way, opening a new way to study dark matter in distant galaxies. These faint trails of stars trace a galaxy’s ...
Sep. 22, 2026 Physicists searching through Large Hadron Collider data found no evidence that the machine has been producing microscopic quantum black holes, but the result sharply narrows where such exotic physics ...
Sep. 22, 2026 Ancient iron meteorites reveal that some of the Solar System’s first solid bodies were built mostly from tiny heat-forged rock beads called chondrules, while water-rich dust was largely excluded. ...