What does Dark Matter have to do with the Big Bang Theory? MSC Bethancourt Lecture Prof. David Toback Texas A&M University Mitchell Institute for Fundamental Physics and Astronomy March 2016

Prologue March 2016 David Toback, MSC Bethancourt Lecture 2 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

Overview of the Talk 3 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 David Toback, MSC Bethancourt Lecture March 2016

What is Dark Matter? 4 David Toback, MSC Bethancourt Lecture March 2016

Dark Matter 5 What is some of the evidence for Dark matter? David Toback, MSC Bethancourt Lecture March 2016

How Stars Move in Galaxies 6 David Toback, MSC Bethancourt Lecture 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 March 2016

7 sics.tamu.edu/to back/Talks/Video /Lab4_SS1_video.swf David Toback, MSC Bethancourt Lecture March 2016

As the Galaxy Turns /Talks/Video/Lab4_GX1_video_slow.sw f 8 David Toback, MSC Bethancourt Lecture March 2016

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) 9 David Toback, MSC Bethancourt Lecture Lots of other evidence for dark matter like gravitational lensing, but that’s for another day… March 2016

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 March 2016

What is the Big Bang Theory? 11 David Toback, MSC Bethancourt Lecture March 2016

Not that Big Bang Theory 12 David Toback, MSC Bethancourt Lecture March 2016

13 A Big Bang Occurred… Then What? The Story of the Universe since the Beginning David Toback, MSC Bethancourt Lecture March 2016

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 David Toback, MSC Bethancourt Lecture March 2016

So What? 15 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 David Toback, MSC Bethancourt Lecture March 2016

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? 16 David Toback, MSC Bethancourt Lecture March 2016

David Toback, MSC Bethancourt Lecture 17 A Brief History of Time 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 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

18 Artists Conception of the Big Bang Bang David Toback, MSC Bethancourt Lecture It all started with a Big Bang March 2016

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 David Toback, MSC Bethancourt Lecture March 2016

20 Later, Quarks Combine to Form Nucleons Quark  Proton Nuclear Reaction Quark qqq  Proton David Toback, MSC Bethancourt Lecture March 2016

21 A Millionth of a Second after the Big Bang The quarks have combined to form Protons and Neutrons David Toback, MSC Bethancourt Lecture March 2016

Creating Heavier Nuclei 22 Proton  Deuterium Nuclear Reaction Proton + Proton  Deuterium David Toback, MSC Bethancourt Lecture March 2016

23 A couple hundred thousand years later: Atoms Proton Electron  Hydrogen Atom ElectroMagnetic Reaction David Toback, MSC Bethancourt Lecture March 2016

24 Wait a Billion Years After about half a billion years, because of gravity, atoms combine to form the first stars and galaxies Our galaxy, the Milky Way David Toback, MSC Bethancourt Lecture March 2016

David Toback, MSC Bethancourt Lecture 25 After about 9 billion years our solar system and the Earth form March 2016

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 David Toback, MSC Bethancourt Lecture March 2016

What does Dark Matter have to do with the Big Bang Theory? 27 David Toback, MSC Bethancourt Lecture March 2016

The Known Particles 28 –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 ! David Toback, MSC Bethancourt Lecture March 2016

David Toback, MSC Bethancourt Lecture 29 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! Big Bang! Then Universe gets bigger What IS the Dark Matter? We don’t know… October 2014 Today: Observe 5 times more Dark Matter than Atoms (by mass) in the Universe

What are scientists doing today to discover Dark Matter? Just mention two of the fun experiments being done here at Texas A&M! 30 David Toback, MSC Bethancourt Lecture March 2016

David Toback, MSC Bethancourt Lecture Some Sources of Dark Matter are Cheap 31 You are here Our Sun is Moving through our Galaxy… Lots of Dark Matter is hitting the Earth every second March 2016

Experiment 32 Dark Matter Particle Atom in Detector Low Temperature Detector Ping I saw it! Eureka! David Toback, MSC Bethancourt Lecture March 2016

David Toback, MSC Bethancourt Lecture Can we Make and Discover Dark Matter? 33October 2014 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

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

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

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

Final Thoughts 37 David Toback, MSC Bethancourt Lecture March 2016

David Toback, MSC Bethancourt Lecture 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 October

Conclusions 39 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! David Toback, MSC Bethancourt Lecture March 2016

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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 41 David Toback, MSC Bethancourt Lecture March 2016

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 October 2014 David Toback, MSC Bethancourt Lecture 42