Prof. David Toback Texas A&M University January 2014

1. Dark Matter and the Big Bang Theory Prof. David Toback Texas A&M University January 2014 David Toback, Saturday Morning Physics

2. Overview Two of the most exciting topics in all of science are Dark Matter and the Big Bang Start with questions: • What IS Dark matter and what is the evidence for it? • What IS the Big Bang Theory? • What does Dark Matter have to do with the Big Bang? • What are scientists doing today to discover Dark Matter? Final Thoughts David Toback, Saturday Morning Physics

3. What is Dark Matter? David Toback, Saturday Morning Physics

4. Dark Matter What is some of the evidence for Dark matter? David Toback, Saturday Morning Physics

5. 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 the orbits of planets and stars as they move around the solar system and galaxy • For the solar system, the data agree perfectly, but for the outer part of galaxies it should look like stars in orbit around a massive center • Problem: This isn’t what the data shows David Toback, Saturday Morning Physics

6. http://people.physics.tamu.edu/toback/Talks/Video/Lab4_SS1_video.swfhttp://people.physics.tamu.edu/toback/Talks/Video/Lab4_SS1_video.swf David Toback, Saturday Morning Physics

7. As the Galaxy Turns http://faculty.physics.tamu.edu/toback/Talks/Video/Lab4_GX1_video_slow.swf David Toback, Saturday Morning Physics

8. 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) David Toback, Saturday Morning Physics

9. Our Place in the Universe You are here In some ways, 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

10. What is the Big Bang Theory? David Toback, Saturday Morning Physics

11. Not that Big Bang Theory David Toback, Saturday Morning Physics

12. A Big Bang Occurred… Then What? The Story of the Universe since the Beginning David Toback, Saturday Morning Physics

13. 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, Saturday Morning Physics

14. 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 David Toback, Saturday Morning Physics

15. 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? David Toback, Saturday Morning Physics

16. 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 • 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 David Toback, Texas A&M University Davidson Scholars

17. Artists Conception of the Big Bang David Toback, Texas A&M University

18. 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, Texas A&M University

19. Later, Quarks Combine to Form Nucleons qqq  Proton Quark Nuclear Reaction Proton Quark Quark David Toback, Texas A&M University

20. A Millionth of a Second after the Big Bang The quarks have combined to form Protons and Neutrons David Toback, Texas A&M University

21. Creating Heavier Nuclei Proton Proton + Proton  Deuterium Nuclear Reaction Deuterium David Toback, Saturday Morning Physics

22. A couple hundred thousand years later: Atoms Proton ElectroMagnetic Reaction HydrogenAtom Electron David Toback, Saturday Morning Physics

23. Wait a Billion Years 0 Our galaxy, the Milky Way After about a billion years, because of gravity atoms combine to form the first stars and galaxies David Toback, Texas A&M University

24. 0 After about 9 billion years our solar system and the Earth form David Toback, Texas A&M University

25. 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, Texas A&M University

26. What does Dark Matter have to do with the Big Bang Theory? David Toback, Saturday Morning Physics

27. 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! David Toback, Saturday Morning Physics

28. 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! Big Bang! Then Universe gets bigger Today:Observe 5 times more Dark Matter than Atoms in the Universe David Toback, Saturday Morning Physics

29. What are scientists doing today to discover Dark Matter? Just mention two of the fun experiments being done here at Texas A&M! David Toback, Saturday Morning Physics

30. 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 David Toback, Saturday Morning Physics

31. Experiment Dark Matter Particle I saw it! Eureka! Ping Atom in Detector Detector David Toback, Saturday Morning Physics

32. 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 David Toback, Saturday Morning Physics

33. More Expensive Dark Matter? High Energy Collisions  Dark Matter ParticlesLHC  ≈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 David Toback, Texas A&M University Research Topics Seminar

34. Aerial View of the LHC 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 David Toback, Texas A&M University

35. How does it do it? Accelerates protons to REALLY high energies, then bashes them together http://people.physics.tamu.edu/toback/Talks/Video/particle_event_full_ns.avi David Toback, Saturday Morning Physics

36. Final Thoughts David Toback, Saturday Morning Physics

37. Interested in learning more? • Physics 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? • General Relativity & Quantum Mechanics • Particle Physics • High School Students: • Get your school to get involved with the Talk Science Program http://faculty.physics.tamu.edu/toback/109/ http://people.physics.tamu.edu/toback/TalkScience/ David Toback, Saturday Morning Physics

38. Conclusions • It’s an incredibly exciting time to be a scientist! • Astronomy, Cosmology and Particle Physics are all coming together! • Starting to 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! Wanna join us? We need your help! David Toback, Saturday Morning Physics

39. End of Lecture David Toback, Saturday Morning Physics