I assume you left something out since two points are always aligned to each other. So it's the sun, the galaxy center and what other point?
I had the same question. I suspect he means that the sun will be on a direct line between the earth and the center of the galaxy. Those wacky Mayans, realizing that if you combine the vast gravitational forces of the sun and the center of the galaxy on the earth, and if the ENTIRE mass of the galaxy were concentrated at a single point at th center you will get 1.00000001 times the gravity of the Sun alone. Obvious catastrophe coming.
Of course, the entire mass of the galaxy is spread throughout the galaxy. So the number is actually much smaller than 1.00000001 (there are actually several more zeros before the last one). [Estimates based on Galaxy mass = 6x10^11 Solar masses and distance to center of galaxy = 1.6x10^-9 AU]. The moon has a much more powerful affect on the earth every time it lines up with the Sun.