The hunt for a second Earth just got a whole lot harder

The search for another planet capable of supporting life has hit an unexpected bump, with astronomers remotely surveying distant exoplanets realizing their assumptions about whether water is present could be deeply flawed. New results from NASA's Hubble Space Telescope have revealed tiny amounts of atmospheric water vapor around three exoplanets initially thought "ideal candidates" when they were identified last year.

HD 189733b, dubbed "Blue Marble" for its distinctive coloration and boasting rainstorms of glass, was spotted in July 2013, while researchers pinpointed HD 209458b and WASP-12b the following December.

At the time, scientists suggested that there was a strong likelihood that water was present, predicting that the "hot Jupiters" proximity to their respective suns would easily reveal it in its gaseous form. Although temperatures on the planets are between 1,500 and 4,000 degrees Fahrenheit, the inhospitable conditions would make water vapor easy to detect and measure.

What was actually measured is vapor only a fraction of what the planetary-formation theories would suggest should be there. Near-infrared light spectrum was examined for the predictable signs of absorption from water, but only between 1/10 and 1/1000 of the amount expected was calculated.

The concern now is that the methods astronomers expected to be able to use to spot planets more friendly to human occupation may not, in fact, be sufficiently sensitive.

"It basically opens a whole can of worms in planet formation. We expected all these planets to have lots of water in them. We have to revisit planet formation and migration models of giant planets, especially "hot Jupiters," and investigate how they're formed" Nikku Madhusudhan, Institute of Astronomy at the University of Cambridge, England

With "much lower water abundances than predicted" the planets dubbed super-Earths will need astronomical tools with far higher sensitivity to make accurate readings, Madhusudhan suggests.