Anyone with kids knows this refrain on a car trip: “are we there yet?”
Science reporters are often looked at as being just as annoying when they ask a researcher “are we there yet?” when it comes to publicizing a major scientific result.
This exploded last week when a Web-replayed public talk by a member of the Kepler space telescope science team went viral –- at least among astronomy geeks who closely follow NASA’s ambitious planet-hunting observatory.
WIDE ANGLE: The Age of the Exoplanet
Web articles and blogs jumped on the presentation by Kepler member Dimitar Sasselov of the Harvard Smithsonian Center for Astrophysics. Soon articles were proclaiming that we found “Earth-like” planets across the galaxy.
Science reporters were primed for this “shoot-ready-aim” response because they are growing impatient with one of NASA’s most exciting and inspiring space observatory missions.
The Kepler team has repeatedly promised over the past year in numerous press conferences that the space-born telescope will find “Earth-sized” planets out there. Just give us time said the principal investigator Bill Borucki of NASA's Ames Research Center.
When the year-proprietary period on Kepler’s first round of observations ended in June, some journalists felt they were the Peanuts comic strip character Charlie Brown, and the Kepler scientists were Lucy and the football. Give us more time the Kepler folks said. We’ll have definitive numbers in February 2011.
In journalism, nine more months of waiting creates a huge news vacuum that is primed for any kernel of a story to expand like the inflationary universe.
That’s just what happened. Once on the Internet, Sasselov’s lecture was translated by reporters. Important ideas got misinterpreted in the translation. This was due in part to the fact that no press conference or substantive press release accompanied the June publication of some of the data.
The semantics over "Earth-like" and "Earth-sized" got confused in stories. Let’s set the record straight. Kepler will never find an Earth-like planet. All Kepler is seeing is the shadows of planets as they pass in front of their star (transits).
A lot of this data is on the hairy edge of believability given the difficulty of making the measurements and interpreting the results. Follow-up observations from ground-based telescopes are needed to confirm the planets are really there. Hence almost all the Kepler targets are cautiously called candidate planets for now.
At the end of the mission, the Kepler database will provide coveted statistics – but no picture of blue-green marbles in space.
Kepler will yield an inventory of planets in the habitable zones around stars like our sun. We will have their diameters, masses, orbital periods, and separation distances. But nothing in the photometry will tell use if they are just parched balls of rock or ocean-glazed paradises.
Identifying a true Earth-like planet will require space telescopes vastly larger than Kepler and planet candidates vastly closer to us then what is in the Kepler field-of-view.
There is a chance NASA’s James Webb Space Telescope might pull this off by 2020. A true inventory of nearby living worlds would require a much larger optical space telescope launched in the 2030-2040 time frame.
In all honesty we can now be enthusiastic in the search for our cosmic cousins, just as Sassalov was in his public talk. The simple truth is that the initial Kepler results, posted online in June, show a rising slope where smaller planets are more numerous than bigger planets.
Borucki has clearly explained that true Earth-mass planets are not yet on the slope because the team has not yet been able to bring these faint transits out of the noise in the data. He’s convinced that Kepler will eventually find plenty of candidates trending downward toward true Earth size.
There is no logical reason that the slope would suddenly take a nose dive as the upper mass limit approaches one Earth-mass. It would be as nonsensical as walking down the beach as seeing only rocks but no pebbles.
What Kepler "first-look" data does support, which I think is practically unequivocal at this point, is that Earth-sized planets must be common. Some fraction of these will be in habitable zones. A subset will have oceans. The precise value is almost irrelevant because of the tremendous multiplier effect of having several hundred billion stars available in our galaxy.
This is why Sasselov is so excited and shared that enthusiasm with his audience. Even the most conservative back-of-envelope guess at this point is that millions of Earths clones are out there.
Sure there are innumerable more observations to make, papers to publish, and someday a full-blown NASA press conference.
“It will take more years of hard work to get to our goal, but we can do it,” Sasselov wrote in an online mea culpa following the media feeding frenzy. "So no new news here -- but more to come later in the year!" he told one news reporter.
Let’s face it, the cat’s out of the bag. And in the age of the Internet, where the public has an appetite for immediate news, waiting for fully vetted science papers to come out seems glacial.
Yes, this is antithetical to the very process of science. Look at the embarrassment when some physicists were in a horse race to announce cold fusion in 1989.
In all sciences the roadway to Ultimate Truth is littered with results that were breathlessly reported, only to be later proven wrong. This is particularly true in the search for exoplanets. Between 1963 and 2005 (before the discovery of the first true planet orbiting a normal star) there were at least 15 reported discoveries of exoplanets that were later retracted.
Depending on the stature of the scientist making the mistake, he or she can be skewered by their colleagues, or at the very least be chastised. False starts have demolished the careers of some scientists.
The simple fact is that science is messy. In astronomy great discoveries are often on the fringe of what a telescope can detect, as is the case with Kepler.
It is misguided to assert, as some science and journalism critics do, that a result cannot be publicized until it is absolutely correct. The truth is that science progresses through infinite mid-course corrections. So it should come as no surprise when the results are later modified or even retracted.
A wrong result can still serve as a catalyst for engaging the public and even other scientists in thinking creatively about a potential new “discovery space.”
In the end the Sasselov news SNAFU was a positive event in that everyday people were simply reminded of the awesome idea the other Earths are likely out there.
"Are we there yet?" Well, almost.
Tags: Alien Life, Astronomy, Current Events, Extrasolar Planets, Kepler Mission
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