Kepler keeps chugging along towards the end of its initial 3.5 year lifespan. But it needs a little more time to complete the work it was sent up to
do. Normally, those funds would be easy to come up with, but given the belt tightening in Washington, Bill Borucki, the missio's longtime leader and
promoter, is getting genuinely nervous. "There is a serious worry that Kepler's funding might not be extended," Borucki told me. That is to say, we
might give up on the quest to find out how common Earths are in the universe for want of $20 million per year. For perspective, that's the cost of
fighting a few hours of the war in Afghanistan. Feel free to fill in your preferred partisan budgetary comparison. Any way you slice it, $20 million is
nothing in the scheme of the Federal budget.
If we care about finding out if we're alone in the universe - and we do - NASA and Congress have got to come together to find $20 million for this
small mission. As University of California exoplanet scientist Greg Laughlin put it, "I do think that extending Kepler's mission would be just about
the very best way that NASA could spend money in these belt-tightening times." I couldn't agree more.
Let me tell you a little more about Kepler and why it needs to reach beyond its planned life. The Kepler spacecraft constantly watches a field of
145,000 stars looking for tiny variations in their brightness, which could indicate that an extrasolar planet has passed between the telescope and the
star. After Kepler makes the initial spot, other telescopes can be pressed into service and astronomers can determine if a planet is, indeed, an
earth-like planet in the habitable zone around its star.
It's easy for Kepler to find planets circling close to their stars. That's because Kepler is waiting for the planets to pass between us and the star.
If that happens often - say, every couple months like the planet Mercury does - Kepler can quickly see that rhythmic dimming in the data and flag it as
But think about a planet like Earth. An alien telescope pointed at Earth and employing Kepler's method would only see us pass in front of our star once
a year. It would take at least three years to start to see the pattern of the regular dimming of our sun's light.
Alien astronomers looking for Earth, though, would have it easier than Kepler's team looking for aliens. That's because our star is unusually
consistent in its brightness. Based on a variety of data, Kepler (and other) scientists assumed that the sun would be a fairly good measure of solar
consistency for sun-like stars. But it's not. Other stars' data is noisier with greater variations in brightness.
"The reason we need to extend the missions is that we were surprised by the universe," Borucki told me. "The way you build up the signal to noise ratio
is to get more transits, so we need more time."