1. Einstein’s Warped Universe Ted Jacobson Department of Physics, University of Maryland

2. "A practical profession is a salvation for a man of my type; an academic career compels a young man to scientific production, and only strong characters can resist the temptation of superficial analysis." Image © The Albert Einstein Archives, The Jewish National & University Library, The Hebrew University of Jerusalem, Israel. Einstein in the Bern patent office, 1905

3. Special relativity (1905) time, space, and mass (E=mc 2 ) General relativity (1915) gravity and inertia warped time and space Einstein’s theories of relativity

4. “…the phenomena of electrodynamics as well as of mechanics possess no properties corresponding to the idea of absolute rest.” “…light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body.” “So we see that we cannot attach any absolute signification to the concept of simultaneity...”

5. Spacetime "Henceforth, space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality” H. Minkowski, 1908

6. timelike lightlike spacelike PAST FUTURE ELSEWHERE like The Light Cone One space dimension not included

7. The twin “paradox” 25 years 24 light-years 7 years SPACE-LIKE TIME-LIKE Time elapsed between two events depends on the path in spacetime, and is LONGEST on the straight path.

8. No time passes along a light ray! 25 years 25 light-years 0 years SPACE-LIKE TIME-LIKE Elapsed time LONGEST on the straight path in spacetime.

9. Spatial distance 4 miles 3 miles 5 miles Distance elapsed between two points depends on the path in space, and is SHORTEST on the straight path. (confusingly OPPOSITE to the case with time)

10. Gravity Universal attraction of two masses. Interpreted by Newton as a “force” that explains both the falling of an apple and the orbit of the moon.

11. Composite photo from NASA/ESA Cassini spacecraft Gravity

12. “I was sitting in the patent office in Bern when all of a sudden a thought occurred to me: if a person falls freely, he won’t feel his own weight. I was startled. This simple thought made a deep impression on me…” “Then there occurred to me the happiest thought of my life…” “The gravitational field has only a relative existence …” “Gravity cannot be held responsible for people falling in love."

13. Parabolic flight allows long free-fall

14. Morag Wightman, choreographer and performance artist Free-fall: straight line in spacetime

15. Gravity is curvature of spacetime Spatial curvature analogy: Initially parallel lines don’t stay parallel apple earth Spacetime time

16. apple earth A B Apple free-fall is the straightest path in spacetime between A & B, and the path of longest time. Time runs slower lower down! How much slower? One billionth of a second per year per foot at the earth’s surface (g/c 2 ).

17. Spatial Analogy: straight line on a curved earth Mercator map: rhumb lines in blue and green; part of a great circle in red

18. Gravity bends light

19. Einstein ring image of a galaxy (Hubble space telescope) Foreground “lens” galaxy background galaxy

20. Multiple images of one galaxy Lensed by a cluster of galaxies

22. (Image by Brian McLeod, Harvard-Smithsonian Center for Astrophysics.) If a black hole with the mass of Saturn (apparent diameter 5 yds) floated by…

23. Black Holes Collapse to a black hole

24. View towards the center of the Milky Way galaxy

25. Stars orbit a giant black hole at the center of our galaxy

26. From Black Holes and Time Warps, by Kip S. Thorne A spinning black hole drags empty space around, like a tornado drags the air

27. Expansion of the Universe closed or open? flat or curved? expand forever? origin? beginning of time?

28. Sprouting Universes?

29. Black hole singularity: an end of time?

30. Fate of a black hole singularity? time ends fractured time continues plump baby Universe born The End

31. A baby universe is born…

32. Black Holes and Time Warps, Kip S. Thorne. A book for the general reader about the physics and astrophysics, with a historical and personal view on the scientists involved. General Relativity from A to B, R. Geroch. An explication of the fundamental concepts with almost no math. Flat and Curved Space-Times, G.F.R. Ellis and R.M. Williams. A textbook introducing the fundamentals to students with no more than basic high school algebra, trigonometry, and the concept of a function. http://www.aip.org/history/einstein/ American Institute of Physics, Einstein web site http://einsteinyear.org/facts/ Institute of Physcs, Einstein web site Further reading