Signs of water on five distant planets have been spotted using the Hubble Space Telescope, with scientists finessing their measurements so as to better differentiate which stand the best likelihood of potentially supporting life. Evidence of water had been initially spotted on several Jupiter-like exoplanets previously, but the team led by the University of Maryland in College Park was able to use infrared wavelength measurements to more specifically calculate the nature of the individual atmospheres.
"This work really opens the door for comparing how much water is present in atmospheres on different kinds of exoplanets," planetary scientist Avi Mandell of NASA's Goddard Space Flight Center said, "for example hotter versus cooler ones."
Five exoplanets have been identified, named WASP-17b, HD209458b, WASP-12b, WASP-19b and XO-1b, each in orbit of nearby stars. The telescope's findings suggest not all water signs are equal: WASP-17b, for instance, and HD209458b apparently have the strongest signals, though the scientists are still confident that results from the other three are consistent with water.
The system in use relies on longer exposures for shots taken by Hubble's Wild Field Camera 3, allowing for more sensitive measurements to be completed. However, initial expectations around the degree to which water would be found proved to be over-ambitious: scientists say that's possibly because each of the five exoplanets has a layer of either haze or dust around it.
One possibility, therefore, is that exoplanets of the type of "hot Jupiters" could simply be prone to having more clouded atmospheres.
Hubble may have found five likely candidates for water being present, but they're perhaps not the most striking discovery the space telescope has made in 2013. Back in July, it spotted HD 189733b, a so-called blue marble exoplanet with 4,500 mph winds, liquid glass rainstorms, and temperatures reaching almost 2,000 degrees Fahrenheit.