Big Questions in Science, Newton, Scientific Revolution, Einstein, Relativity, Quantum Mechanics, Big Bang

1. Big Questions in Science:
From the Very Small
to the Very Large
Sebastian de Haro
AUC Open Day, 17 January 2015

2. The Course: Quick Introduction
• Academic core course for non-science majors
• It can be used to fulfil the science requirement
• No science background expected or required
• Students with a science background (‘beta-profiel’ or similar) can still take the
course and benefit from the different perspective
• They normally provide good contributions to the class discussion!

3. The Teacher(s): Quick Introduction
• Three teachers, one for each section
(physics & astronomy, earth science, biology)
• My own background: Dutch/Spanish, theoretical physicist,
40 research papers, 1500 citations
• Now new background in philosophy of science: second PhD at the
University of Cambridge
• Interest in philosophical questions obvious in the course!
• Teacher and tutor at AUC since 2009. Courses:
• Quantum Physics, Statistical Mechanics,
Symmetries and the Quantum Universe, Philosophical Problems

4. The Course: More Details
• Taught twice a year (fall and spring): 50 students
• Tailor-made for AUC students’ needs in HUM/SSC
• Connection to humanities/society
• Different student backgrounds
• Importance of science in everyday life
• To become a critical citizen on various issues one needs basic understanding
of the state of the art of science
• Provide an overview of the very basic concepts of science fostering the
development of such an understanding
• Identify the Big Questions in Science, and how these questions are being
(have been) addressed

5. General Aims
• Basic understanding of the state of the art:
• Overview of the basic concepts of science needed to understand the
Big Questions
• Identify concrete Big Questions in science, old and new:
• What makes them into Big Questions?
• How do scientists address them?
• Their social/cultural impact (and impact on them!)

6. What the students say…
• “I really liked Sebastian's slides; they were very helpful for the exam
preparation. I didn't really like the idea of 'learning questions' but it
ended up being super helpful. I used to hate physics, and was
surprised to have liked it so much after taking the course. It's
probably thanks to Sebastian too.”
• “It's demanding for a social science student, but you learn a lot.”

7. Big Questions Connecting Circle:
Space- and time-scales
3 Time and relativity
4 Quantum mechanics
5 Our cosmic origins
1Classical physics
2The Scientific Revolution

8. Length Scales: Powers of Ten
Documentary film Powers of Ten (9 min)

9. Different length scales distributed on the
Big Questions Connecting Circle 10 𝑛
= (1 with 𝑛 zeroes)

10. Examples of scientific theories distributed on the
Big Questions Connecting Circle

11. Examples of sciences distributed on the
Big Questions Connecting Circle

12. Newton’s Big Question
Why does the Moon not fall on Earth?

13. It is in constant fall but its direction keeps changing
The Moon behaves as any other physical object, for instance an apple!

14. The Scientific Revolution
• Copernicus vs. Ptolemais
• Kepler (laws of motion of the planets)
• Galilei (mechanics, popularisation of Copernicus)
• Newton (laws and Big Question: What is gravity?)
• What made it a revolution?
• Novel science (modern science is born)
• Influence on society (‘paradigm shift’)
• Societal influences on the genesis of the revolution

15. Einstein’s Big Questions
• What is time and how do we measure it? (Augustine, Galilei)
• What is gravity and how does it work? (Newton)
• Preliminary: energy (forms of energy, conservation of energy)
• Cultural influences (both ways): dynamism of space-time and extra
dimensions in art (e.g. cubism, Flatland)
• Einstein’s mathematical derivation of the relativity of time (‘time dilation’)
using only basic trigonometry!
• Theory of relativity: nice illustration of the ‘scientific method’

16. The General Theory of Relativity: Black Holes
• Qualitative explanation of the general theory of relativity
• Experimental evidence for the existence of black holes, predictions

17. Big Questions in Science, fall 2014. SdH, AUC

18. Quantum Mechanics:
Connections between Micro and Macro
• Basic review of the history and main principles of quantum
mechanics: atoms, electrons, light
• Many properties of large systems are related to quantum mechanics

19. Example: Spectral Lines
• Specific wavelengths of light emitted/absorbed by particular atoms
• Explained by quantum mechanics

20. Example: Planck Spectrum and Spectral Lines
• Explain a large number of macroscopic phenomena: colour of light,
absorption of radiation in the atmosphere by greenhouse gases
• Used in astronomy to determine the distance of stars to us
• Used in cosmology to test the theory of the Big Bang

21. The ‘Weirdness’ of Quantum Mechanics:
Schrödinger’s Cat
What is measurement? What is an ‘observer’?

22. Big Questions Connecting Circle:
Space- and time-scales
3 Time and relativity
4 Quantum mechanics
5 Our cosmic origins
1Classical physics
2The Scientific Revolution
Energy

23. Big Question: How Did the Universe Start?
And How Do We Know This?
• … and what are OUR cosmic origins?
• Most of the matter in the universe was created shortly after the big bang
(hydrogen, helium)
• But there was not enough time to form heavier atoms, from which our
body is made (carbon, oxygen). This was formed inside stars!
• And then again, only 4% of the universe is made of matter
• The remaining 96%… Dark matter?... Dark energy?

24. The Big Bang

25. The Big Bang
• Time-line: what happened when, and how do we know?
• Experimental evidence for the theory

26. More Connections…
• Between the history of the universe and the history of science
• Not by chance!

27. Big Questions in Science, spring 2014. SdH, AUC

28. Thank you!