Is momentum real, or completely illusory?

It's Saturday night and I'm watching the first inning of Game 3 of the World Series when my son calls me from Citizens Bank Park in Philadelphia. Only minutes before the game began, he and his friends were able to purchase choice seats a few rows up from the Yankees dugout for just $200 apiece, a lucky outcome chalked up to the pouring rain conditions. It's the first home game of the series for the Phillies, and I can actually feel my son's excitement over the phone, it's palpable and contagious. We quickly end our conversation and I return to watch the game, but now I'm caught up in the thrill myself and the momentum begins. The home crowd is absolutely deafening and the Phillies surge 3-0 in the first two innings. Surely that's an insurmountable lead, and when I text that to my son, he replies that he's never been a part of such jubilance and joy, the experience itself is obviously priceless.

Suddenly, that early inning momentum abruptly ends for the Phillies. The Yankees start to score and predictably, the boos become what's deafening now, but within an hour or so, even the booing starts tapering off. By the 7th inning I can't bear watching any longer and I actually turn off my TV. I'm not a rabid Phillies fan by any means, but the momentum has been transferred, and albeit vicariously, I'm feeling all the disappointment I know my son is feeling at that moment.

Momentum isn't just an athletic phenomena. Barack Obama harnessed the power of momentum during the election last year. There seemed to be a pivotal point in October 2008, (like right now in the World Series) where McCain just began to sink rapidly into an almost deathly plunge. Was it real or illusory? Given another month, could McCain have overcome all the forces working against him (Sarah Palin's exposed weaknesses, the devastating economy) to reclaim his former hold? I don't think so.

Given another chance tonight, can the Phillies recapture their momentum? The Yankees now have a definite psychological edge going into this 5th game of the series. What do you think - is that real or illusory? Can the Phillies overcome the Yankees momentum?