World-changing events come in many guises. Sometimes they are highly visible, like the launch of Sputnik, the fall of the Berlin Wall, or the current political upheaval in the Arab world. We rarely know what the eventual outcome and import of such events will be, but there is little doubt that what has happened is Important and will impact us all.
Other world-changing events are more subtle, with impacts that take a long time manifest themselves, but are no less dramatic. The invention of the telegraph and the creation of the Internet were not trumpeted by the forebears of Anderson Cooper swooping in with live reports, but events like these inexorably led to a changed world. (The first public demonstration of the telegraph by Samuel Morse was in 1838; his famous "What Hath God Wrought" message was not sent until 1844. Seven years later, Western Union was founded, and the rest is history.)
Yesterday, NASA and its Kepler Mission team announced a small landslide of new planets and planet candidates. In one announcement, the number of known/suspected planets went from just over 500 to over triple that number, at around 1700. Not only that, but the number of known Earth-sized planets went from a zero or a few (depending on your definition) to nearly 70. And this is certainly just the tip of the iceberg. In two years, Kepler has discovered more planets than all of humanity had discovered in all of history. Think about that for a second. Granted, we've been getting better at finding planets recently, but Kepler's pace is still far beyond all other efforts combined.
In many regards, yesterday's data avalanche was expected. We knew Kepler was working well, and there had been many hints and insider slips that the team was finding planets everywhere in Kepler's sight. But the fact remains that, before the Kepler Mission, we did not know how common Earth-sized planets are. And now we are starting to get the answer. They are very common.
One of the questions humans have been asking for ages is, are we alone in the Universe? We don't have an answer to that yet, but Kepler has taken a giant step along the path to answering that question. There are profound implications in the Kepler team's work, not just for understanding how the Universe works, but for understanding our place within this Universe. There are potentially huge philosophical implications that extend far beyond the science of astronomy.
The Kepler Mission still has work to do. Its primary goal is to count how common Earth-sized planets are at distances from their parent stars where life similar to that on Earth might be possible. Yesterday we got some initial hints, but the final answer is still years away.
Undoubtedly, yesterday's Kepler data release will fundamentally transform our study of planets around other stars, in our understanding, our future observing programs, in the challenges to our ideas about planet formation, and even in the basic questions we astronomers are asking. But I also feel that there will be a societal impact extending far beyond the astronomy of planets. It may take years or decades for that impact to be felt, and this impact will be driven not just by the Kepler mission, but also by the hard work and discoveries of astronomers who will work (and have been working for nearly two decades) on planets around other stars.
The universe of astronomy has changed, even if that change was mostly anticipated. And I think these discoveries will change the rest of the world. How long we have to wait, and where will this change lead society I do not know. But I do know that this is Important.