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.
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.
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.
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.
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.
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.
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.