This thing is -270°C and is EVERYWHERE

The Cosmic Microwave Background: A Discovery of the Universe

Introduction to the Cosmic Microwave Background (CMB)

• Diana introduces the concept of a pervasive signal that exists everywhere in the universe, which was discovered accidentally.

Historical Context of CMB Discovery

• In the 1960s, radio astronomers Robert Wilson and Arno Penzias at Bell Labs noticed an unusual constant background noise while testing a microwave antenna.

• Despite attempts to eliminate potential sources of interference, including cleaning the antenna thoroughly, they could not identify the origin of this persistent noise.

• They contacted researchers at Princeton University and learned that they were detecting the cosmic microwave background signal.

Understanding CMB's Significance

• The CMB is radiation from shortly after the Big Bang, providing crucial insights into the early universe's conditions.

• Although it permeates space, its energy levels are too low to pose any danger to life on Earth.

Origins and Characteristics of CMB

• The CMB traces back to nearly all events following the Big Bang when matter and antimatter filled a hot dense universe with particles and radiation.

• Initially opaque due to high density, light could not travel freely until about 380,000 years post-Big Bang when atoms began forming during recombination.

Expansion and Cooling of the Universe

• As the universe expanded rapidly after its inception, it cooled down significantly; this cooling process allowed for atomic formation.

• Diana uses an analogy involving dry shampoo to explain how expanding gases cool down as pressure decreases.

Recombination and Light Travel

• After recombination occurred, light that had been trapped in plasma began traveling freely across space for billions of years.

• Initially emitted in infrared wavelengths, this light has since redshifted into microwaves due to ongoing expansion.

Detection and Mapping of CMB

• Wilson and Penzias received a Nobel Prize for their discovery; subsequent missions like NASA’s COBE (1989), WMAP (2001), and ESA’s Planck have mapped detailed images of CMB.

Insights Gained from CMB Studies

• Current average temperature of CMB is approximately 2.7 Kelvin with tiny fluctuations indicating quantum variations from early universe conditions.

Dark Energy Connection

• Fluctuations in CMB may provide insights into dark energy through phenomena like the Sunyaev-Zeldovich effect affecting brightness maps based on galaxy clusters' interactions with photons.

Measuring Galactic Movement

• Observations reveal blue shifts on one side and red shifts on another side of CMB allowing scientists to measure our Milky Way's speed through space at around 600 kilometers per second.

Conclusion: Importance of CMB

• The discovery solidified evidence for Big Bang theory; remnants can still be observed today as static on old televisions—an echo from when our universe was just beginning.