Tubegazing: 'Planet Earth' and 'Boomer Century'

The Boomer Century: 1946 – 2046 (PBS, March 28, 9-11 p.m.): For the 78 million Americans born between 1946 and 1964, this two-hour documentary is a look at a generation shaped by assassinations, resignations, and wars. It's also a reminder of how the baby boomers, in turn, shaped a world through idealism, feminism, and sheer numbers. The show looks soberly at the weaknesses of what many have dubbed a spoiled, self-absorbed generation, even as it deconstructs the many strengths of the boomer cohort, including its dedication to global change and continuing engagement with social activism. If you happen to be a boomer, it's a reminder of your great privileges. For everyone else, it's a good primer on the forces behind just about every aspect of modern life, from the presidency to global warming. Grade: A

Planet Earth (Discovery Channel, series debut March 25): This 11-part, groundbreaking show – the first nature series filmed entirely in high definition – shows viewers sights never before captured on film: A polar bear emerging from hibernation, a shark in the act of swallowing a seal, deep ocean vistas that look like alien planets, rare Tibetan foxes. "Planet Earth" took more than five years to assemble, with footage from more than 200 locations, from Himalayan mountain ranges to the swallow caves of Mexico. Not to quibble about so ambitious an undertaking – the cinematography is, indeed, breathtaking – but in the race to deliver the images it seems that the producers forgot about the script, which is merely serviceable. The sensational camerawork deserves better. Grade: B+