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.