Hyper-22 b


Kepler-22 b” was all over the news yesterday. An “Earth twin” at “22 Celsius”! The Holy Grail of planet searches.

Let’s quote  Don Pollacco, from Queen’s University Belfast, on the BBC website,

“There is a conference going on, they want to generate some publicity – that’s why you are hearing this now.”

NASA’s Kepler mission has already discovered more than 1,000 planets, including dozens in the habitable zone. There is nothing particularly special about the object christened Kepler-22 b among this group. The timing of the announcement

“is a $200m question because that’s the cost to continue this space mission. This space mission is nearing the end of its life and to continue it will cost that much money.”

Media hype is a big force in exoplanet research, of course, and the closer one gets to the issue of extra-terrestrial life, the more hysterical it gets. The basic reason I think is that while the people interested in any specific research number in the thousands, and those interested in exoplanet science in general in the millions, there are billions interested in aliens. But the time devoted by each group to thinking about the issue is inversely proportional to their numbers. So when the specialist gives it a couple of hours of thought, the newspaper reader gives about ten milliseconds. “Earth twin?” Yes. “Liquid water?”, yes. “Life?”, not sure. Hey, still taking about this? Look at the polar bear biting one of its own cubs.

Earth and its twin, to scale

Cover from the movie "Twins"

As far as exoplanet hype goes, though, this one seems fair. The Kepler mission has been stunningly successful, most spectacularly in its main objective: to

determine the frequency of Earth-type planets in or near the habitable zone of Solar-type stars. More than a thousand credible transiting planets have been identified, including enough at large distances and low mass to determine the frequency of Earth-like planets with reasonable extrapolation. Borucki et al. (2011) include 28 sub-Neptune candidates in the habitable zone.

This is the big news for Kepler this year, and since it is statistical in nature and not clearly associated with actual planets and definite news items, identifying  some representative flagship case makes sense, especially at this crucial time when the possible continuation of the mission is being decided.

Let’s end with a quote from the UK Telegraph daily:

“Kepler 22b, the planet which scientists say hold the best hope yet for future human habitation, could have continents, oceans and creatures already living on its surface, they believe.”

We believe…


Feature Image: FP

Further Reading:

NASA press release

Kepler-22 b, Borucki et al.


About Author

I am a professor of planetary science at the University of Exeter. My specialty is the study of exoplanets, in particular the observation and modelling of exoplanet atmospheres. I have done my PhD a the University of Geneva and worked in Chile, France and Switzerland.