Big telescopes; Bigger Questions; and Really Big Mistakes

Imagine its 1930, and you’re a veteran Harvard astronomer, talking to ordinary folk about your work.
It’s the most exciting time in your field since Isaac Newton, but its surely sort of embarrassing too.
Those folk might reasonably say to you: “Hey, just ten years ago, most of you people thought our Milky Way galaxy was the whole universe – and now this Hubble fellow tells us there are billions of galaxies just like ours out there.”
Or – referring to Cecilia Payne - they could say: “What’s more, you people all thought the stars were made of IRON, like my CAR, until just last year, when a LADY – someone’s assistant! – proved they’re made of hydrogen gas, which couldn’t be more different! Have you got ANYTHING right?”
Now – in 2010, after a decade of equally stunning new discoveries – Harvard’s astronomers face a remarkably similar time of excitement and embarrassment.
Embarrassment, because – until very recently - astronomers thought they at least knew the basics of what the universe was made of.