1. Science
Notes: Stnd 14
Date
Standard 14: 8.ESS1.1
The Big Bang
Research, analyze, and communicate that the universe began with a period of rapid expansion using evidence from the motion of galaxies and composition of stars.
Science and Engineering Practice(s)
Obtain and communicate information, Construct Explanations
Crosscutting Concepts
Cause and Effect, Stability and Change
I Can Statement
...I can explain how the cosmos expanded to form the universe in
its current form (The Big Bang).

2. Big Bang Model

3. Big Bang: Chronology The universe begins ~13.7 Billion years ago
Evidence suggests that...
...the universe began as a single tiny point.
...the universe began as a tremendous expansion (called inflation)
... matter, space, and time were formed in an instant.

4. ~three minutes after the Big Bang
Big Bang: Chronology
~three minutes after the Big Bang
The universe expanded from the size of an atom to about the size of a softball.
Energy converted into matter (IAW Albert Einstein’s equation.)
E=mc2
Energy formed into clumps of matter that we call protons, neutrons and electrons.
These sub-atomic particles later formed into atoms.

5. ~several hundred thousand years later
Big Bang: Chronology
~several hundred thousand years later
Atoms formed (mainly Hydrogen but also some Helium).
The early Universe was about 75% Hydrogen and 25% Helium. It is still almost the same today.
Hydrogen Atom
Helium Atom

6. ~200 to 400 million years later
Big Bang: Chronology
~200 to 400 million years later
First stars formed (due to gravity and nuclear fusion).
First galaxies formed (due to gravity).

7. This is how our sun was formed
Gravity forms stars from clumps of hydrogen.
Clumps of hydrogen atoms were pulled together by gravity. Next, gravity caused nuclear fusion to occur, and a new star was “ignited.”
This is how our sun was formed

8. Big Bang: Chronology ~4.6 billion years ago
Our solar system formed (due to gravity).

9. 1) Universal expansion and Hubble’s Law 2) Background radiation
Big Bang: Evidence
1) Universal expansion and Hubble’s Law
2) Background radiation
3) Quasars
4) Stellar formation and evolution
5) Speed of light (Speed Limit)

10. Link (3:22): What is Red Shift?
1) Universal expansion and Hubble’s Law
a) Hubble observed the majority of galaxies are moving away from us and each other
b) The farther away, the faster they are moving away from us.
c) Red Shift (Doppler Effect): objects moving away from us are tinted red. Objects moving toward us are blue shifted.
Link (3:22): What is Red Shift?

11. 2) Background Radiation Link (4:52): Cosmic Microwave Background
a) cosmic microwave background radiation-discovered in 1964.
b) The amount of radiation matched predictions
c) The C.O.B.E satellite (1989 to 1993) confirmed that this background radiation is evenly spread across space.
Link (4:52): Cosmic Microwave Background

12. 3) Redshift of Quasars
Quasi-stellar (meaning: star-like) radio sources now commonly called Quasars were first discovered in the 1950s
Link (2:45): Quasars
Quasars have incredibly powerful luminosities (extremely bright)
Their red shift reveals that these objects are very far away, and per the speed limit of light, we are able to see far back in time to the early formation of galaxies.

13. 4) Stellar Formation/Progression
We observe the life cycles of stars across the universe using ground based telescopes and space-based telescopes.
We can observe stars forming, evolving, exploding, re-forming, etc.
Link (2:15): Birth of Our Solar System
We infer that these same processes occurred in the distant past to form the first stars.

14. 5) Speed of Light (Speed Limit)
The speed of light is a universal constant.
This speed is 300,000 km/s (186, 000 miles per second)
A light-year is the distance that light travels in 1 year. The light we see today from a star 500 light years away is 500 years old.
We can see stars that are billions of light years distant. Therefore we can see what the universe looked like when it was forming.
Link (3:35): Facts About the Speed of Light