1. What does Dark Matter have to do with the Big Bang Theory?
Lunar
Society
What does Dark Matter have to do with the Big Bang Theory?
Prof. David Toback
Texas A&M University
Mitchell Institute for
Fundamental Physics and Astronomy
May 2016

2. David Toback, Lunar Society
Prologue
We live in a time of remarkable scientific understanding Scientists are arrogant/crazy enough to think that it may be possible to solve major problems in Astronomy, Cosmology and Particle Physics with a single discovery that ties all three together Idea: Dark Matter is a particle that was created right after the Big Bang and has had a major impact on the evolution of the Universe and the stuff in it Goal of this talk: To show you how all this might just tie together
May 2016
David Toback, Lunar Society

3. David Toback, Lunar Society
Overview of the Talk
Will talk about some of the most exciting questions in all of science one-by-one:
What IS Dark matter and what is some of the evidence for it?
What is the Big Bang Theory?
What does Dark Matter have to do with the Big Bang and the evolution of the Universe?
What are scientists doing today to discover Dark Matter?
Final Thoughts
May 2016
David Toback, Lunar Society

4. David Toback, Lunar Society
What is Dark Matter?
May 2016
David Toback, Lunar Society

5. What is some of the evidence for Dark matter?
May 2016
David Toback, Lunar Society

6. How Stars Move in Galaxies
Start by considering the case that there IS no Dark Matter in galaxies
Can use laws of gravity to predict two things:
1) The orbits of planets as they move around the solar system and
2) Stars as they move around a galaxy
Prediction: both have very massive centers so we expect the data to look consistent with that
Data:
For the solar system, the data agree perfectly
For the stars in the outer part of galaxies, the prediction doesn’t work at all
May 2016
David Toback, Lunar Society

7. David Toback, Lunar Society
May 2016
David Toback, Lunar Society

8. David Toback, Lunar Society
As the Galaxy Turns
May 2016
David Toback, Lunar Society

9. David Toback, Lunar Society
Data well explained by lots of “Dark Matter” we can’t see This is where it gets its name In some sense, the name is a statement of almost all we know about it (it doesn’t interact with light, and it has mass)
Lots of other evidence for dark matter like gravitational lensing, but that’s for another day…
May 2016
David Toback, Lunar Society

10. Our Place in the Universe
You are here
The Dark Matter surrounds the galaxy like the water in a fishbowl surrounds a fish in the middle of the bowl
Not exactly the same… denser in the middle because of the pull of gravity
May 2016
David Toback, Lunar Society

11. What is the Big Bang Theory? David Toback, Lunar Society
May 2016
David Toback, Lunar Society

12. Not that Big Bang Theory
May 2016
David Toback, Lunar Society

13. A Big Bang Occurred… Then What?
The Story of the Universe since the Beginning
May 2016
David Toback, Lunar Society

14. Observe lots of galaxies with the world’s best telescope
We notice that All the far away ones are moving away from us VERY quickly
May 2016
David Toback, Lunar Society

15. So What?
All the stuff in the galaxies appears to have come from a single point in space ~13.7 billion years ago
Name this time The Big Bang
 A moment of Creation
What happened in the past?
Run the clock backward in time
May 2016
David Toback, Lunar Society

16. Slightly more complicated than that…
As best as we understand the Universe began with a Big Bang
A REALLY Big Bang
Then what?
How did we get from the bang to the Universe we have today?
May 2016
David Toback, Lunar Society

17. David Toback, MSC Bethancourt Lecture
A Brief History of Time
Zero
One millionth of one second after the Bang
A few minutes
A few hundred thousand years
100 million to 1 billion years
9 billion years
~13.7 billion years
The Big Bang  produces lots of particles
Quarks combine to form protons and neutrons
Protons and Neutrons combine to form the nucleus of an atom
Nuclei and electrons combine to form atoms
Atoms combine to form Stars and Galaxies
The Earth and our solar system forms
You listen to me talk
October 2014
David Toback, MSC Bethancourt Lecture

18. Artists Conception of the Big Bang
It all started with a Big Bang
Bang
May 2016
David Toback, Lunar Society

19. The very early Universe
Lots of free particles just hanging around…
Universe is so hot that quarks can’t combine to make protons/neutrons
May 2016
David Toback, Lunar Society

20. Later, Quarks Combine to Form Nucleons
qqq  Proton
Quark
Nuclear Reaction
Proton
Quark
Quark
May 2016
David Toback, Lunar Society

21. A Millionth of a Second after the Big Bang
The quarks have combined to form Protons and Neutrons
May 2016
David Toback, Lunar Society

22. Creating Heavier Nuclei
Proton
Proton + Proton  Deuterium
Nuclear Reaction
Deuterium
May 2016
David Toback, Lunar Society

23. A couple hundred thousand years later: Atoms
Proton
ElectroMagnetic Reaction
Hydrogen Atom
Electron
May 2016
David Toback, Lunar Society

24. Our galaxy, the Milky Way David Toback, Lunar Society
Wait a Billion Years
Our galaxy, the Milky Way
After about half a billion years, because of gravity, atoms combine to form the first stars and galaxies
May 2016
David Toback, Lunar Society

25. After about 9 billion years our solar system and the Earth form
After about 9 billion years our solar system and the Earth form
May 2016
David Toback, Lunar Society

26. Recent History: Life on Earth
Earth is about 4 or 5 billion years old
Evidence that microbial tracings existed on Earth about 3.5 billion years ago
Humanoids, like “Lucy” existed a mere 3 million years ago
Homo-sapiens at around 100,000 years ago
May 2016
David Toback, Lunar Society

27. What does Dark Matter have to do with the Big Bang Theory?
May 2016
David Toback, Lunar Society

28. David Toback, Lunar Society
The Known Particles
No known particles have the properties of Dark Matter
Other reasons to believe there are new fundamental particles to be discovered
For example, we just discovered the Higgs Boson
Maybe Dark Matter is a New Particle!
May 2016
David Toback, Lunar Society

29. What IS the Dark Matter? We don’t know…
Hypothesis: The Dark Matter in the Universe is made up of LOTS of particles that we haven’t discovered yet!
Best Guess: Huge numbers got created in the Early Universe like everything else and are still here today!
Then Universe gets bigger
Big Bang!
Today: Observe 5 times more Dark Matter than Atoms (by mass) in the Universe
October 2014
David Toback, MSC Bethancourt Lecture

30. What are scientists doing today to discover Dark Matter?
Just mention two of the fun experiments being done here at Texas A&M!
May 2016
David Toback, Lunar Society

31. Some Sources of Dark Matter are Cheap
You are here
Our Sun is Moving through our Galaxy…
Lots of Dark Matter is hitting the Earth every second
May 2016
David Toback, Lunar Society

32. David Toback, Lunar Society
Experiment
Dark Matter
Particle
I saw it! Eureka!
Ping
Atom in Detector
Low Temperature
Detector
May 2016
David Toback, Lunar Society

33. Can we Make and Discover Dark Matter?
High energy collisions between particles in the Early Universe
Recreate the conditions like they were RIGHT AFTER the Big Bang
If we can produce Dark Matter in a collision then we can STUDY it
October 2014
David Toback, MSC Bethancourt Lecture

34. Detector Dark Matter Particle Proton Proton Dark Matter Particle
More Expensive Dark Matter? High Energy Collisions  Dark Matter Particles LHC  ≈1 ps after the Big Bang
Detector
Dark Matter Particle
Proton
Proton
Ok… Its more complicated than this since Dark Matter Particles don’t easily interact with detectors…
Nor do we usually produce them directly
Dark Matter Particle
October 2014
David Toback, MSC Bethancourt Lecture

35. Aerial View of the LHC Lake Leman Geneva Airport p p
27 km in Circumference!
One of the largest and
the most complex scientific
instrument ever conceived &
built by humankind
Lake Leman
Geneva Airport
Collides high
energy protons
Two huge detectors
CMS p p
ATLAS
October 2014
David Toback, MSC Bethancourt Lecture

36. David Toback, MSC Bethancourt Lecture
How does it do it?
Accelerates protons to REALLY high energies, then bashes them together
October 2014
David Toback, MSC Bethancourt Lecture

37. David Toback, Lunar Society
Final Thoughts
May 2016
David Toback, Lunar Society

38. Interested in learning more?
Physics & Astronomy department now offers a course entitled “Big Bang & Black Holes”
(ASTR/PHYS 109)
Covers Stephen Hawking’s “Brief History of Time”
Origin and Evolution of the Universe
How do stars form?
What is Dark Matter? Dark Energy?
What are Black Holes?
More on General Relativity, Quantum Mechanics and Particle Physics
Has a lab (if you want) and can be used as a Science Distribution credit
There is an option to take is an Honors class
May 2016
David Toback, Lunar Society

39. David Toback, Lunar Society
Conclusions
It’s an incredibly exciting time to be a scientist!
Astronomy, Cosmology and Particle Physics are all coming together
Perhaps we understand the role of Dark Matter in the Universe since the Big Bang!
If our understanding is correct, a major discovery may be just around the corner!
May 2016
David Toback, Lunar Society

40. David Toback, Lunar Society
End of Lecture
May 2016
David Toback, Lunar Society

41. David Toback, Lunar Society
Abstract
Scientists have entered a golden age of discovery. We are starting to be able to answer some of the most exciting questions ever asked, including questions that touch on the Big Bang, the fundamental building blocks of nature, and the Dark Matter that fills the Universe. In this talk I will talk about Astronomy, Cosmology, Particle Physics and The Universe and the reasons to think that the biggest things in the Universe (like the Universe itself) and the smallest things (like quarks and electrons) are inextricably linked. Indeed, many of us believe there is a new, fundamental particle just around the corner waiting to be discovered that could all these things together
May 2016
David Toback, Lunar Society

42. David Toback, Lunar Society
Prologue
(Apologies for the simplistic definitions)
Astronomy is the study of things we can see through telescopes… Stuff in Universe (space)
Cosmology is about trying to understand the origin and evolution of the Universe
Particle Physics is about trying to understand the smallest things that make up the stuff in the Universe
May 2016
David Toback, Lunar Society