Orgin of Atoms

Origin of Atoms

  • Atoms in our bodies originated from stars.

    • Initial formation: Hydrogen, helium, and lithium atoms formed right after the Big Bang.

    • Heavier elements were formed later in stars.

Big Bang Theory

  • Approximately 13.8 billion years ago, a singularity led to the Big Bang.

  • Following the Big Bang:

    • In the first picosecond: only elementary particles like quarks and electrons existed.

    • After one microsecond: protons and neutrons began to form.

    • Within minutes: Hydrogen ions (H+), deuterium (D+), helium (He2+), lithium (Li3+) emerged; these particles had an air-like density.

    • For 400,000 years: Temperature dropped and no further fusion occurred.

  • Matter began to clump and stars formed, leading to galaxies and planets.

  • The concept of the Big Bang evolved from a joke among physicists to a widely accepted theory.

Cosmic Expansion

  • Everything in the universe is moving away from us—evidence comes from the Doppler effect.

    • Sound waves: Frequency changes based on the movement of the object (approaching vs. receding).

    • Light waves: If an object emitting light is stationary, color remains the same. If moving toward or away, wavelengths change:

      • Toward: Higher frequency, shorter wavelength (blue shift).

      • Away: Lower frequency, longer wavelength (red shift).

  • Redshift indicates that distant galaxies are moving away from us, supporting the expansion theory of the universe.

Evidence of Expansion

  • Redshift: Key evidence supporting the expansion of the universe.

  • Cosmic Microwave Background Radiation (CMBR): Remnant from the early universe, almost uniform and clumpy.

    • Evidence indicates earlier high density and high temperature conditions.

  • Tiny differences in CMBR's temperature help matter to clump together—promoting star formation and galactic structures.

Formation of Stars and New Elements

  • As matter clumped together and gravitational forces increased:

    • Temperature rose, initiating nuclear fusion once again.

    • Stars began forming along with galaxies.

  • Nuclear reactions in stars lead to the creation of new atoms:

    • Hydrogen nuclei fuse to form helium, releasing energy.

    • Helium nuclei can form carbon and other heavier elements.

    • Fusion processes differ from typical chemical reactions.

Element Formation Timeline

  • After the Big Bang: Elements up to lithium (Li) formed in early universe.

  • Elements from carbon (C) to iron (Fe) formed in red giants.

  • Elements beyond iron, including uranium (U), formed in supernovas.

  • Our Sun: A third generation star formed after two previous stellar explosions, containing heavy elements like iron, indicating its origin from earlier stars.

The Legacy of Stars

  • Formation of the Sun:

    • Accumulated material led to planet formation around the Sun.

  • Humans and all matter: Composed of elements formed in stars—often referred to as 'stardust.'

    • Indicates the profound connection between humans and the cosmos.

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