Earth Sci Chapter 1 Flashcards
(24 cards)
What observations led to the acceptance of the Big Bang theory?
Three Pillars of Proof
o Recession of stars/galaxies (Hubble’s Law)
o Characteristics of microwave background radiation
o Abundance of light elements
What are the steps of the scientific method?
Hypothesis, Theory, Law
What is hypothesis?
an educated guess based upon observation (sometimes only one observation)
cannot be supported or rejected
cannot be proven to be true
What is theory
the foundation of science, and summarizes a hypothesis (or group of hypotheses) that is supported by repeated testing and observation
what is law
explains a body of observations. no exceptions found
What is a singularity
- No readily understood definition
- An area in space-time where gravitational force is so high that all known laws of
physics break down and do not apply
What is the Big Bang theory? What does it describe?
- The theory of how the universe was created
- It describes a gigantic expansion that was the beginning of space and time
What are the three main lines of observation that support the Big Bang theory?
doppler effect, cosmic microwave background, abundance of light elements
What is the big bang theory
an effort to explain exactly what happened at the beginning of the Universe
At the birth of the universe, time and space were created in a gigantic expansion that emanated from a ‘singularity’
what is a gigantic expansion?
Think of an infinitesimally small balloon, which in the tiniest fraction of time, suddenly expands and keeps on expanding. In that tiny instant, time and space had a finite beginning inside the balloon
Doppler effect
An object coming towards you making sound will have compressed sound
waves (louder)
An object moving away making sound will have extended sound waves (lower)
Cosmic Microwave Background (CMB)
The hot light photons from the big bang have lost energy and dropped into
microwave wavelength (out of visible light)
Appears as static noise when played by a sensitive microwave radio
receiver
Abundance of light elements
Hydrogen (75%), Helium (25%), Lithium (trace)
can be explained only if they originated from one single ratio of the first subatomic particles of matter that can be formed from a super-hot environment
What are the possible shapes of the universe?
Sphere, saddle shaped, and flat
Sphere universe
- Positive curvature
- Closed universe
- Finite size but without boundary
saddle shaped universe
- Negative curvature
- Infinite and unbound
Flat universe
- Infinite and boundless
What makes up the most matter in the universe, dark matter or stars?
Dark matter > stars
Dark matter: 27%
Stars, etc: 5%
What is the difference between dark matter and dark energy?
Dark matter is unable to be seen, gives off no electromagnetic energy, has gravitational attraction
Dark energy is opposite of gravity, it repels matter, controls expansion of space
What is the difference between dark matter and dark energy?
Dark matter is unable to be seen, gives off no electromagnetic energy, has gravitational attraction
Dark energy is opposite of gravity, it repels matter, controls expansion of space
How can we know the age of the universe? (3 ways)
Radioactivity, Hubble’s Expansion Constant, Cosmic Microwave Background Radiation
Radioactivity
- Radioactive elements that break down into other components are tracked
- Measure how long the process took based on which radioactive process produces said gasses from the first elements
- Between 11.5 and 17.5 billion years, at least 13.2 billion
Hubble’s Expansion Constant,
- Using Hubble’s constant equation, there is a t variable
- Possible to determine age of the most distant light sources
- Between 13 and 4 billion years
Cosmic Microwave Background Radiation
- Offer most accurate view of conditions in early Universe
- A model based on the CMB signal map when first photons were produced
by Big Bang
- 13.80 +/- 0.04 billion years
