DW test

• Unanswered Questions About the Big Bang

  • What caused the Big Bang?

  • What existed before the Big Bang?

  • What is the nature of dark matter and dark energy?

  • What lies beyond the observable universe?

• How Cosmology “Sees” into the Past

  • Light takes time to travel; distant objects show past states.

  • Telescopes capture ancient light from stars and galaxies.

  • Cosmic Microwave Background Radiation (CMBR) provides a snapshot of the early universe.

• Role of Technology in the Scientific Origin Story

  • Telescopes (e.g., Hubble, JWST) reveal distant galaxies.

  • Spectroscopy analyzes light to determine composition and movement.

  • Particle accelerators simulate early universe conditions.

  • Radio telescopes detect CMBR from the Big Bang.

Telling the “Story” of the Big Bang: The First Structures and the First Atoms

• Big Bang as a “Theory” or “Paradigm”

  • A well-supported scientific explanation based on evidence.

  • A dominant framework in cosmology, subject to refinement.

• Timeline of Early Universe

  • 0 seconds – Singularity, infinite density and temperature.

  • 10⁻³⁵ sec – Inflation expands universe faster than light.

  • 10⁻⁶ sec – Quarks combine into protons & neutrons.

  • 1 sec – Electrons form, universe is a hot plasma.

  • 3 min – First nuclei (hydrogen & helium) form.

  • 380,000 years – Universe cools, atoms form, CMBR released.

• Key Terms and Definitions

  • Energy – Driving force of the universe.

  • Four Fundamental Forces – Gravity, Electromagnetism, Strong, Weak forces.

  • Gravity – Attracts masses together, forms galaxies.

  • Electromagnetism – Governs light and charged particles.

  • Weak Force – Responsible for radioactive decay.

  • Strong Force – Binds atomic nuclei together.

  • Dark Energy – Accelerates universe expansion.

  • Matter & Anti-Matter – Early annihilation left mostly matter.

  • Quarks – Building blocks of protons & neutrons.

  • Electrons – Negatively charged particles.

  • Protons & Neutrons – Make up atomic nuclei.

  • First Atoms – Hydrogen & helium, formed ~3 min after Big Bang.

  • Dark Matter – Invisible mass influencing galaxy motion.

  • Plasma Universe & CMBR – Hot plasma cooled, allowing atoms to form and releasing CMBR.

• Three “Extreme” Characteristics of Early Universe (David Christian)

  • Extremely Hot – Trillions of degrees.

  • Extremely Dense – Matter packed tightly together.

  • Extremely Small – Universe was minuscule.

  • 1940s Equivalent Conditions – Atomic bomb tests provided insight into extreme temperatures and energy densities.

• Why 380,000 Years is a “Mini-Threshold”

  • Universe cooled enough for atoms to form.

  • Light was able to travel freely (CMBR).

  • Transition from plasma to structured universe.

What’s the Evidence?

• Doppler Effect & Redshift (Edwin Hubble)

  • Light from galaxies shifts red, showing they are moving away.

  • Supports the expanding universe model.

• Spectroscopy & Absorption Lines

  • Analyzes star light to determine composition & movement.

  • Confirms universe expansion and element formation.

• Parallax Method

  • Measures distance to nearby stars using Earth's orbit shift.

  • Helps scale distances in the universe.

• Cepheid Variables & Luminosity (Henrietta Leavitt)

  • Pulsating stars with known brightness used as cosmic yardsticks.

  • Key to measuring distances beyond our galaxy.

• Cosmic Microwave Background Radiation (George Gamow, Arno Penzias, Robert Wilson)

  • Residual heat from the Big Bang, detected in all directions.

  • Strong evidence for the Big Bang Theory.

• Light Years & the Extreme Deep Field

  • Light-year: distance light travels in a year (~5.88 trillion miles).

  • Hubble Deep Field shows galaxies billions of years old, confirming cosmic history.