1. Jim Sullivan

2.  Big Bang Theory  Dark Matter and Dark Energy  Detecting Dark Matter  Radiation  SNO and SNOLAB  Prototype Detector  Pulse Shape Discrimination  Data and Homework  Summary

4. Matter Formed into Galaxies

5.  Studied speed of stars in other galaxies in the 1930’s

8.  Found the outer stars were going “too fast”  Gravity was not enough to explain speed

10. V star F=m s V 2 /r F=G m g m s /r 2 r

11.  Not enough mass in galaxy to retain outer stars at the speed they were moving  Missing mass called Dark Matter  Expected missing mass to be: ◦ Dark stars (didn’t ignite) ◦ Black holes ◦ Asteroids  Found some, but not enough, by a lot

16.  Galaxies are six times heaver than the visible matter in them  Call the missing matter “Dark Matter”  Currently thought to be subatomic particles created in the Big Bang  Search is on for Dark Matter

17.  Distribution of galaxies not uniform  Measure positions of galaxies, plot in computer  Found to form within filaments of Dark Matter

20.  Gravity always attractive  Expansion of the universe should slow down  Actually found it is speeding up  Must be an unknown force pushing universe apart  Repulsive rather than attractive  Called Dark Energy  From E = mc 2, can convert energy to mass  Dark Energy makes up about three quarters of the stuff of the universe

22.  Dark Matter holds galaxies together by increasing gravitational attraction  Dark Energy kicks in as universe expands, preventing gravitational collapse

23.  …Detecting Dark Matter