PBS TV: Inside Einstein's Mind

New documentary:

On November 25th, 1915, Einstein published his greatest work: general relativity. The theory transformed our understanding of nature’s laws and the entire history of the cosmos, reaching back to the origin of time itself. NOVA tells the inside story of Einstein’s masterpiece. The story begins with the intuitive thought experiments that set Einstein off on his quest and traces the revolution in cosmology that is still playing out in today’s labs and observatories. Discover the simple but powerful ideas at the heart of relativity, illuminating the theory—and Einstein’s brilliance—as never before. From the first spark of an idea to the discovery of the expanding universe, the Big Bang, black holes, and dark energy, NOVA uncovers the inspired insights and brilliant breakthroughs of “the perfect theory.”

This is mainly about general relativity. It attributes to Einstein the idea that gravity and curved spacetime geometry are the same thing. This was actually not Einstein's view.

22:06 CARROLL: Because spacetime has a geometry, he thinks to himself, "Well, maybe it's the actual shape of spacetime itself 22:13 that is giving rise to gravity."

NARRATOR: After months of work, Einstein has an extraordinary idea. 22:24 "What if spacetime is shaped by matter, 22:31 and that's what we feel as gravity?"

JOHNSON: In struggling to figure out what causes gravity then, 22:38 Einstein has this great insight. It is simply that a mass distorts the shape of spacetime around it. 22:46 So you get rid of this force of gravity, and instead we have curvature of spacetime. 22:53 In Einstein's universe then, if space were empty, it would be flat. There'd be nothing going on. 22:59 But as soon as you put objects down, they warp the space and time around them, 23:04 and that causes a deviation of the geometry so that now things start moving.

23:14 DIJKGRAAF: Everything wants to move as simple as possible through space and time. 23:20 But Einstein tells us that mass sculpts space and time, 23:26 and it's the curved motion through this sculpture that's the force of gravity.

23:33 KNOX: We have this feeling that the reason I can feel pressure on the soles of my feet, that the reason things are going to drop when I throw them, 23:39 are because there's a force attracting us down to the center of the earth. What general relativity tells you is that's not the right way 23:46 to think about what's going on there. What's really going on is that your natural path in spacetime 23:54 would take you to the center of the earth, and what's actually happening is the floor is getting in the way, it's pushing you upwards.

23:59 CARROLL: When we look at it, we go, "Ah, the force of gravity" But Einstein says, "No, no, no, the curvature of spacetime."

24:12 NARRATOR: It's a stunning insight. Just as an ant might feel forces pulling it left and right 24:21 as it walks over crumpled paper when it's simply the shape of a surface dictating its path, 24:27 Einstein saw that what we feel as the force of gravity is in fact the shape of the spacetime we're moving through.

It concludes with how Einstein ruined Physics. His example convinced the brightest minds of the world to stand around blackboards trying to solve the riddle of the universe with pure thought.

49:10 Here at the Institute for Advanced study, where Einstein worked, the world's leading theoretical physicists 49:17 are trying to solve the problem Einstein never could: finding a single set of rules 49:23 that applies to both the cosmic and atomic scales. A unified theory.

49:31 The Holy Grail of physics. We are now in what at this time is the school of physics. 49:39 So here, people are still struggling with many of the same issues that Einstein would struggle 49:44 and are still trying to capture the laws of the universe 49:49 from the very small to the very large in a single equation. 49:54 And it's still blackboards that are the weapon of choice.

50:00 The brightest minds of the world are coming here to work 24 hours, seven days a week, 50:08 struggling to grasp the great mysteries of the universe. 50:13 And I think we are still driven by the same dream: that at some point, we can capture everything in elegant mathematics.

50:21 NARRATOR: 100 years after Einstein transformed our understanding of nature, 50:27 the stage is set for the next revolution.

CARROLL: When we finally move beyond Einstein, 50:34 it might be another singular genius that comes along-- someone struggling in a poor school in Kenya right now 50:39 that we don't know about. Or it might be 20 different people with 20 different points of view gradually building brick-by-brick 50:46 to finally figure out a more comprehensive view that includes general relativity in it. 50:58

DIJKGRAAF: I think the most important thing that you learn from Einstein is just the power of an idea. If it's correct, you know, it's just unstoppable. 51:09 It's extremely encouraging that he was able with pure thought to solve the riddle of the universe.