Chapter 1 Flashcards
What started everything and when?
The Big Bang
13.82 billion years ago
What was it like when the universe started and today
Hot start with 10^30 K
and now cold with 3K
What happened from the start to present
Forces existed, elementary particles formed, protons & atoms formed, galaxies, stars, us formed
What was the first evidence of the Big Bang
Penzias and Wilson in 1965
What is cosmic microwave background
Radiation from Big Bang that is faint glow in sky of microwaves
What caused formation of atoms
Excited electrons used atom (3000K) to make light that has been background radiation
What is order of formation of all things
Galaxies, stars, planets, humans
How was everything started
Gravity separates into fundamental particles (quarks and electrons) where quarks combine to protons and neutrons that then combine to atomic nuclei to make atoms to make light to make matter into clouds to make galaxies and stars
How do astronomers explore locally
Probes & Instruments
How do astronomers explore the universe
Light
How fast does light travel at a finite speed
300,000 km/s
186,000 mi/s
What is the light travel time for the Moon
1 second; 243k miles
How far is Sun from Earth
8 minutes light travel and 93 million miles
What js a light-year
Distance light can travel in 1 year
How far is a light year
10 trillion km
What is scientific method
Observation | Hypothesis | Prediction | Test Prediction
What is scientific theory
Explain variety of observations with principles
Supported by evidence
Has not failed in tests of validity
Makes predictions
What can’t a scientific model include
Cannot include divine intervention | explanations rely on natural causes
How does science progress
From developing and testing models of nature that explain observations
What must a scientific model have
Testable predictions about natural phenomena
What are patterns in stars
Constellations that define our origin
What is the Celestial Sphere
Universe from Earth’s POV
What is Local Sky
Universe from person’s POV
Ultimate goal of scientific theory
Physical Law
Hallmark#1
No divine intervention
Explanations for phenomena from natural causes
Hallmark#2
Observations explained simply and through testing of models
Hallmark#3
Must have testable predictions about natural phenomena that can be revised
R*
Rate of star formation
fp
Fraction of stars with planets
ne
number of habitable planets
fl
Fraction of habitable planets with life
fi
Fraction of life planets with IQ
fc
Fraction of intelligent civilizations that can communicate/have technology
L
How long does civilization last
