NASA scientists may feel like they are close to finding habitable planets way out in space, but today is not the day they make their big discovery.
According to the Washington Post, scientists using the Hubble Telescope observed three exoplanets orbiting sun-like stars, but found no evidence of sufficient water on their surfaces. The swing-and-miss actually surprised the scientists because their prediction model indicated the planets should be abundant with water vapor.
Dubbed HD 189733b, HD 209458b, and WASP-12b, the three exoplanets were all determined to be in their star's "habitable zone." NASA scientists believed the planets, which were between 60 and 900 light years from Earth, have surface temperatures of 1,500 to 4,000 degrees Fahrenheit.
At this temperature, they thought whatever water was on the planet would be vapor, making it easy to detect. However, Hubble observations found only about a tenth to one-thousandth of the predicted water vapor.
"Our water measurement in one of the planets, HD 209458b, is the highest-precision measurement of any chemical compound in a planet outside our solar system, and we can now say with much greater certainty than ever before that we've found water in an exoplanet," Nikku Madhusudhan, of the Institute of Astronomy at the University of Cambridge, England, said in a press release. "However, the low water abundance we have found so far is quite astonishing."
Madhusudhan led the team of researchers who published their study in the Astrophysical Journal Letters.
"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," he said. "We should be prepared for much lower water abundances than predicted when looking at super-Earths (rocky planets that are several times the mass of Earth)."
