Big Bangs and Dark Matter

1. Big Bangs and Dark Matter Dr Alan Barr Physics lecturer University of Oxford

2. The very BIG Hubble

3. Spectra and redshifts

4. Mega parsec = 3.26 million light-years = 3.1 x 1016 m

5. Echos of something big WMAP satellite

6. What was formed: matter Only three elements are formed in the Big Bang All other elements are formed in stars Differences between materials are due simply to the number of protons and electrons in their atoms.

7. The very SMALL (what we see) x 5 x 10000 cell nucleus: 10 μm dna: 2 nm cells: 50 μm x 5-> x 20 x 50000 proton atom: 100 pm atom nucleus: 2 fm A hundred billion atomic nuclei lined up in a row would be the width of a human hair

8. The whole story?

9. Commonplace particles Leptons Quarks Electron, e μ τ e u c t u quark νe νμ ντ d s b Photon, γ Force carriers Out there? d quark Gluon, g γ g G h W Z Not to scale! The bit we understand… Matter & Forces Matter Particles  Components and theory largely understood (maths)  Underlie all of physics, astronomy, chemistry, life!

10. Big questions What is dark matter made of? NEED HIGH ENERGY COLLISIONS! Where has all the anti-matter gone? Where do the particles get their mass from? What else is out there?

11. Blue Peter guide  Take some protons Lots of these in nature!  Make them move (very fast)  Bang them togetherIt’s good to stand back at this point Photograph the debrisYour camera-phone may not be fast enough!

12. http://www.youtube.com/theATLASExperiment#p/u/0/NhXMXiXOWAA

13. Our accelerator The Large Hadron Collider, CERNGeneva (Swiss-French boarder) Electric waves speed particles up 1232 magnets each 8-Tesla bend protons in a circle Large Hadron Collider

14. Note concerning “high energy” FOURTEEN THOUSAND BILLION VOLTS Spark could jump 5000 km in air(~radius of The Earth)

15. Our detectors ATLAS LHCb

16. Big questions What is dark matter made of? Where has all the anti-matter gone? Where do the particles get their mass from? What else is out there?

17. The Higgs Field Endows space with a kind of all-pervasive sticky-treacle Interactions with this treacle gives mass to particles They then travel slower than the speed of light In this analogy the Higgs Bosonis a treacle-ball – something which allows us to see the treacle itself Mass and the “Higgs Boson” High energy collisions ought to make Higgs Bosons

18. The “tentative” evidence

19. What is Dark Matter? Normal: Made from atoms Includes stars, planets, people… Dark matter: Unknown substance (not atoms) May be a “fat cousin” of normal lightWe hope to make & study it at CERN Dark energy: Even weirder! Need to “see” the invisible!

20. Invisibleexotic missing Visibleparticle short-livedexotic proton proton short-livedexotic Invisibleexotic x z Visible particle How to “see” the invisible?

21. Useful? Future discoveries will lead to new technologies Uses of the electron

22. Big Bangs and Dark Matter • Astronomy very large (See what’s out there) • Particle physics very small (Do it “at home”) • Both explore the structure, building blocks and evolution of the universe • Complementary information • New discoveries lead to new technologies

24. Discovery of the electron J.J.Thompson needed just over 13 V to remove electrons from atoms. First subatomic particle to be isolated, in 1897