Earth-like planets Gliese 581 g and d likely don't exist, study says

[n2doc]

Another study has cast doubt on the existence of two of the first Earth-sized planets "discovered" outside our solar system that could potentially host liquid water, and therefore life. But it may also have uncovered a way to make detecting new planets easier.

When the discovery of Gliese 581 g was announced in 2010, there was a lot of excitement because it was in the habitable zone of its red dwarf star – the "Goldilocks" region – not too hot and not too cold – where liquid water, and therefore life, could potentially exist. The planet appeared to be just 1.2 to 1.4 times larger than Earth, and therefore likely to have a rocky surface.

Another planet in the system, Gliese 581 d, announced in 2007, was on the edge of the habitable zone.

"They were very high value targets if they were real," said Paul Robertson, a postdoctoral researcher at Penn state University and the lead author of the new study, published this week in Science.

"But unfortunately we found out that they weren't."

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http://www.cbc.ca/news/technology/earth-like-planets-gliese-581-g-and-d-likely-don-t-exist-study-says-1.2696945

[DreamGypsy]

1. This finding represents the way science works best.

Especially when a particular result or observation is anticipated (desired), the approach should always be skeptical. If you're looking for evidence of "habitable" planets, eg. the presence of H2O, then the important questions should include "How can I disprove the presence of water" or "What other phenomena might cause measurements similar to those expected for water?".

But human nature works the other way. It's like a kid roaming the grocery store - if you're hoping for some candy, you don't start your search in the vegetable aisle. Scientists like to have "positive" results, so the they look for for the data to support them. Fortunately the process of publication, review, and counter proposal, as exhibited by Dr Robertson and colleagues, acts to balance the natural bias to affirmative results.

Determining the actual conditions on the Gliese planets will probably take more observations and analysis techniques before a consensus is achieved, but it will happen. That's the beauty of science.