Just three words: "Transit timing variations"

“How many of you read the main Nature article?” Dan Fabrycky asked this morning. He’s a charismatic speaker and one of the lead authors on the scientific paper that announced the discovery of Kepler-11, a six-planet star system, splashed on the cover of Nature the first week of this past February. Hands went up all around the dim lecture hall, many of them belonging to scientists who study astronomy and exoplanets for a living.

“And how many of you read and understood all of the supplemental materials?” he continued, referring to the paper’s appendices in which the nitty-gritty, mathematical details of the techniques used to discover and analyze them were outlined.

Only a handful of…well, hands, stood above a sea of silent scientists. “A few of the co-authors,” Fabrycky dryly noted, and the audience roared with laughter.

These are strange and exciting times for astronomers studying exoplanets. As an outside observer, it’s thrilling to watch, for the tools they’re bringing to bear on Kepler’s data are not tried-and-true algorithms that can be dug up out of textbooks like numerical recipes. Nor are they techniques that scientists have learned to do as students and perfected and polished throughout their careers until they’re like second nature. Instead, we have the pleasure of watching scientists in the prime of their careers doing brilliant work and writing the textbook on these techniques as they invent them—literally. No, really, I mean, literally. Here it is:

Published only last December, it’s a collaborative effort from the elite group of planet hunters to bring their techniques to the scientific masses. Remarkably, it sells for a mere $26 at Amazon, a price point subsidized by NASA in an attempt to get the book into the hands of as many students—and scientists—as possible.

The point is that this is a fast-moving field, and even professional astronomers are unfamiliar with many of its newly-minted tools. Fabrycky sensed this and told the crowd that his goal in his talk was to “get you feeling comfortable with these techniques”.

The specific technique Fabrycky was referring to in this morning’s session on the architecture of exoplanetary systems at AAS—and one of the buzzphrases for the entire conference—was “transit timing variations“, or TTVs, a phenomenon that arises in multiplanet systems.
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Kepler hailed on opening day of AAS Boston

The talks are over and the posters packed up—Day 1 of the summer meeting of the American Astronomical Society is officially over (minus the drinking and late-night carousing)—and from one perspective, NASA’s Kepler Mission, its supremely successful planet-hunting satellite, was the star of the show. But advances were everywhere you looked, from Noreen Grice’s talk on making astronomy accessible to the blind by emphasizing a tactile approach, to a presentation on the upcoming Pan-STARRS wide field imaging survey, to Alan Marscher’s vocal and guitar performance of his astronomy-themed songs.

Nevertheless, if AAS Seattle last January was Kepler’s coming out party, where it floored the astronomical community by announcing an abundance of earth-sized, potentially habitable planets in distant star systems, then today was a performance review bordering on the ecstatic, emphasizing its emerging roles in a diversity of fields, and the progress its scientists have made in analyzing its data.

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AAS Boston! #aas218

The empty press office at #aas218.

Blogging at you live from the American Astronomical Society’s summer meeting in Boston!

AAS is the main scientific body for astronomers in the US, and as such, it’s one of the biggest in the world. It hosts conferences twice a year, a summer and a winter meeting. The winter meeting is by far the larger of the two—about 3000 astronomers show up; considering that there are only about 10,000 professional astronomers in the worldwide community, the winter meeting is one of—if not the—biggest news cycles for astronomy of the entire year. Some of the highest profile science results are announced there—such as the Kepler Mission’s finding of 54 habitable zone exoplanet candidates this past winter in Seattle.

The summer meeting is a bit smaller; I heard someone mention that registration numbered about 1300. Still, it’s a major event, a flat-out, balls to the wall extravaganza of science, talks, posters, and schmoozing. I’ve never been to one before, but it’s exhilarating (and already a bit exhausting). And conveniently for me, this year the meeting is in Boston, at the Westin hotel in Copley Square, just a 20 minute T ride from my apartment in Brookline.

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Scrap paper

What can a single piece of scrap paper hold?

Imagine going down to your local university library and coming across a piece of paper in the archives, long-forgotten, covered in the dusts of time. You pull it out and gaze upon the scribbles from the hand of a man from 400 years ago…

…who is drafting a letter to the prince of Venice. He’s trying to sell him something—a new military instrument. It’s called the “telescope”, and its seller, a man named Galileo, says it enables a commander to “discover the ships of the enemy two hours before they can be seen with the natural vision…and to judge their strength and be ready to chase them, to fight them, or to flee from them.” The pitch has the easy charm of a used car salesman and the bravado of a man who is attempting to profit off of an invention he did not, in truth, invent (he got the idea from lens makers in Holland).

But in the bottom margin, something else—something completely different—is recorded: scribbles, sketches, and figures. Observations from the same instrument—but of what? Stars, of some sort, evidently. Some are repeated with minor variations, as if the man who sketched them was driving himself mad attempting to tease out the secrets of what he’s seeing. And some are indecipherable—in particular, two figures mysteriously marked “10” and “11”…

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The wrong time to be alive

“Is it true that the starlight we see is millions of years old?” one of my students asked me this semester. “So that when we look at the sky we’re actually looking back into the past?”

It was a cold, clear night in Boston, and I was teaching a night lab session on the roof the department building, observing with a few 8-inch telescopes.

“Exactly,” I said, with a big grin on my face. He’d hit upon one of the most poetic truths of astronomy. I spoke loudly enough for the rest of the students on the roof to hear, switching into lecture mode. “Light can’t travel infinitely fast, so it takes some time to reach us. We’re not seeing the stars as they are now, we’re seeing them as they once were—years, centuries, maybe tens of thousands of years ago. The light from the galaxies you can see through the telescopes is millions of years old, or older.”

His response genuinely surprised me. “That’s so depressing!”

“Really?” I asked. “Why?”

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