Big Bang Theory
Atoms in our bodies originated from the stars, formed after the Big Bang.
Initially, only hydrogen, helium, and lithium atoms existed shortly after the Big Bang, while heavier elements were formed in stars.
Timeline of Formation
Approximately 13.8 billion years ago: The universe began as a singularity, then underwent a rapid expansion (Big Bang).
Immediately after Big Bang: Only elementary particles (quarks and electrons) existed, no atoms.
After ~1 microsecond: Protons and neutrons formed as the universe cooled.
A few minutes later: Formation of light nuclei (H, D, He, Li) with a low density similar to air.
400,000 years later: Matter clumped into stars; no further fusion occurred in the interim.
After the Big Bang, stars formed where atoms combined to create heavier elements through fusion.
The Big Bang theory gained credibility over time, transitioned from joke to established scientific theory due to accumulating evidence.
Doppler Effect for Light:
Similar to sound, when light-emitting objects move towards us, light wavelengths compress (blue shift); moving away stretches the wavelengths (red shift).
Redshift indicates galaxies are moving away, evidencing universal expansion.
Cosmic Microwave Background Radiation (CMBR):
Observations show nearly uniform background radiation correlating with the early dense and hot universe, allowing us to trace back to the Big Bang.
As the universe cooled, tiny temperature fluctuations led to gravitational forces,
Matter clumped, raising temperatures further, which reignited nuclear fusion.
Stars formed from clumping of hydrogen and helium, initiating the production of heavier elements through nuclear reactions.
Fusion Process: Hydrogen atoms fuse under extreme pressure and temperature to create helium, releasing vast amounts of energy.
Helium can further combine to create heavier elements (carbon, etc.).
Elements up to iron are formed in red giants; those heavier are produced in supernovae.
Our Sun is a third-generation star, which formed from the remnants of previous supernova explosions.
Formation of the Solar System: A disk of matter formed around the Sun, leading to the creation of planets.
The presence of heavy elements (like iron) in the Sun indicates its origins from earlier stars.
The atoms in our bodies are remnants of stars and cosmic events stretching billions of years ago, emphasizing the notion that we are made from stardust.