SUMMARY BIG HISTORY (PART ½)
This is a summary of the first half of the Big History course, taught at the
University of Amsterdam in 2019.
This document contains:
❖ A summary of all the important Big History events from the Big
Bang up to the emergence of life, based on the book ‘Big History
and the Future of Humanity’ (2015) by Fred Spier (Chapters 1-5).
❖ A summary of all the additional course lectures held at the
university of Amsterdam in 2019.
❖ The answers to all the learning goals from modules 1-7 (through the
summaries of the book and lectures).
Every module-summary is indicated with the title used in the course (e.g. ‘How did
the universe originate’) followed by the corresponding book chapter (e.g. Chapter 1)
and consists of different paragraphs.
Some paragraph’s have a ‘(lecture only)’ notification. This means that the theory from
that paragraph isn’t discussed in depth in the book Big History and the Future of
Humanity, but was discussed during a guest lecture. These paragraph’s can be
skipped if you’re only interested in the content of Spier’s book.
MODULE 1: INTRODUCTION TO BIG HISTORY
(CHAPTER 1 & 2)
WHAT IS BIG HISTORY?
1. A modern origin story
2. An explanatory theory of everything
3. A way to look at even the most detailed aspects of our world
Big History is important because it bridges the gaps between different domains (written
history, biology, astronomy) and presents a more coherent image of how we, and the
universe surrounding us, came into being.
BIG HISTORY AS A MODERN ORIGIN STORY
,In Big History, we don’t focus on everything that happens. Instead, we focus on things that
we currently consider important.
This makes Big History into a modern origin story (origin stories, like the Bible, also focus on
the things the people that tell them find important).
This also means that Big History doesn’t just reflect our past, but also mirrors current
society.
THEORY OF EVERYTHING: COMPLEXITY
In Big History, we look at the history of the entire universe. To organise this huge amount of
information, Big History focusses on the pattern of increasing complexity through time.
SECOND LAW OF THERMODYNAMICS & ENTROPY
This increase in complexity in itself is strange. According to the Second Law of
Thermodynamics, the entropy (= disorder) of a closed system tends towards a maximum.
This means that our universe should
only get more disordered instead of
creating ordered complexity (as is being
pictured in this image →).
This is because through random
movement, it’s constituents should
tend to disperse.
However, this is not the case…
COUNTERING SECOND LAW OF THERMODYNAMICS: ENERGY!
Our universe is mostly empty, but locally it contains a lot of complexity (including stars,
planets and life on earth). This means the Second Law of Thermodynamics is being
countered by something.
This is done by energy.
Energy can be invested to bring stuff together in complex ways (thus countering the
Second Law).
,If necessary, energy can be invested to keep these things that way.
This means that higher levels of complexity require denser energy flows through them, to
keep them the way they are (see image).
Source: lecture Esther Quadaecker, Big History Course UvA, Semester 1 (2019).
Note: complexity isn’t measured by size. The sun is a very big structure, but since it’s power
density is much lower than that of our brains, animals or plants, it means it’s less complex.
GOLDILOCKS CONDITIONS
Energy flows through matter aren’t the only thing necessary to create complexity.
In addition to energy flows, you need Goldilocks Conditions (= GC from now on). These are
circumstances like temperatures, pressures, etc. that are just right for a certain form of
complexity to emerge and sustain itself.
The GC for each form of complexity are different. For example: the sun needs very different
conditions to exist than we as humans do.
Different kinds of GC for different kinds of complexity will be highlighted in this summary,
based on the book Big History and the Future of Humanity by Fred Spier.
SUMMARY
1. Big History focusses on moments in history where complexity increases.
2. Complexity = energy flows (through matter) + Goldilocks Conditions
, MODULE 2: HOW DID THE UNIVERSE ORIGINATE?
(CHAPTER 3)
WHY DO WE THINK THE UNIVERSE HAS A BEGINNING? (OLBERS’
PARADOX)
The universe may seem infinitely big (and infinitely old) to us, but it probably isn’t. Why do
we think this?
One scientific reason why the universe can’t be infinitely big and old, is called Olbers’
Paradox.
According to this paradox, the night sky wouldn’t be dark if the universe would be infinitely
old and big. This is because an infinitely big and old universe would contain an infinite
number of stars. The light from this infinite number of stars would be reaching us all the
time, making it impossible for the sky to be dark.
The night sky is dark, however, which means the universe has an end (in space) and a
beginning (in time).
WHY DO WE THINK THE UNIVERSE STARTED WITH THE BIG
BANG?
Big Bang theory: At the very moment our universe emerged, an enormous amount of
undifferentiated energy and matter was packed infinitely close together. Here, no
complexity existed. From that extreme moment, the universe started to expand very fast
(“exploded”) under the influence of an unknown force, and it has done so ever since.
There’s three independent sets of data that exist, that are used as evidence for the Big
Bang scenario.
1. A red shift in light caused by the Doppler-effect
2. Cosmic Microwave Background Radiation (CMBR)
3. Hydrogen and helium percentages in our universe
1: A RED SHIFT IN LIGHT CAUSED BY THE DOPPLER-EFFECT
,When we look at images of stars or galaxies far away from us, we see that the smaller and
fainter these images are – and thus the further away these stars and galaxies are from us –
the redder the light that they emit is.
This is called a red shift.
This red shift is caused by the fact that frequencies (= wavelengths) of light change
depending on how the source of the light moves. This is called the Doppler effect.
When a source of light moves towards you, the frequencies compress. When it moves away
from you, the frequencies are stretched out.
(this also goes for sound: think about an ambulance that has a higher-pitched siren when it
nears you, and a lower-pitched siren when it passes you).
Compressed frequencies are bluer.
Stretched out frequencies are redder.
SUMMARY
❖ The further away a galaxy or star, the redder the light they emit.
❖ Light becomes redder when the object that emits the light is moving away from
you.
❖ So, the bodies that are furthest away from us, are moving away from us the fastest.
CONCLUSION
1. This means the universe is expanding!
2. The fact that the universe is expanding now, means it was smaller, hotter and
denser in the past.
DETERMINING YOUR DISTANCE TO A STAR (lecture only)
There’s different ways to determine your distance to a star.
1. Parallax method (for stars that are relatively close)
Measuring the distance of a close star by comparing it’s position in relation to an
unmoving background (= stars that are very far away) throughout the seasons.
, It’s location in relation to it’s background shifts depending on if we look at it in fall
or spring, e.g. Through that shift, we can calculate it’s distance to us (see image).
2. Pulsing frequencies (for stars further away)
The further pulsing frequency of a star determines the brightness.
If there’s a high pulsation frequency (which indicates bright light), but the star looks
dim, it’s far away from us.
If there’s a low pulsation frequency (which indicates dimmer light), but the star still
looks relatively bright, it’s closer to us.
3. Looking at supernovae (to look at other galaxies)
A certain type of supernova has a certain type of fixed brightness. By determining
what supernova you’re looking at, and then determining how bright it is, you can
calculate how far away that supernova (or the galaxy it’s part of) is from you.
DETERMINING WHAT KIND OF STAR YOU’RE LOOKING AT:
ABSORPTION SPECTRUM & EMISSION SPECTRUM (lecture only)
1. The type of light coming from a star, tell us what that star is made of.
White light can split into different light frequencies = the rainbow colours!
Depending on what the star and the gas cloud surrounding is made of, different
rainbow colours are “absorbed”. This is called the absorption spectrum of a star.
These colours are missing in the light that’s being emitted by the star (= called
emission spectrum).
So by looking at the light coming from a star, and by determining what light
frequencies are missing, we can determine what the star is made of.
