zero (and it will remain so)

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In just a handful of years, what used to sound like something exciting (“discovering exoplanets”, “finding potentially habitable planets”) has become truly mind-boggling. Let’s face it: we’ve found over 4,000 exoplanets. Does it make sense to keep talking about something that happens every two and a half days? Does it make sense to turn the news about the latest stone we’ve discovered into authentic contests Let’s see who finds its most curious feature?

It seems that if. Even if that means confusing everyone with what it means for a planet to be (or not) “habitable”.

What does it mean when a planet is in the ‘habitable zone’? In general, when we talk about “habitable zone” most of us tend to think of a “new Earth”, but the truth is that reality is far from that. In the habitable zone (as it is normally defined) there is room for both a paradisiacal Eden and a “toxic mousetrap incompatible with complex life”.

For decades we have been trying to find planets that are simply at a distance from their sun that allows liquid water to exist. That is to say: we have not been too demanding. No one is unaware that yes, life as we know it needs liquid water: but that does not mean that water is enough. For this reason, in recent years astrophysicists have tried to devise “a way to take all the observational data that is available and develop a prioritization scheme”; something that allows us to go a little beyond liquid water.

habitability

E.Schwieterman et al.

The history of Kepler-442b. This is how in 2015, Rory Barnes, Victoria Meadows and Nicole Evans, three astrophysicists from the University of Washington, discovered that Kepler-442b, a small planet located 1115.5 light years from us (precisely the planet that has become popular these days), was more ‘inhabitable’ than Earth. That is, Barnes, Meadows and Evans published a “comparative habitability index” which gave Earth a habitability of 0.829 and Kepler-442b a habitability of 0.836.

don't call him "New Earth"call it "toxic mousetrap incompatible with complex life": rethinking habitable zones

This, of course, means nothing.. That is, these scientists were not saying (as we have read these days) that “they have a 97% probability of being inhabited.” What they were looking for was to find better indexes to identify the best candidates for further investigation. Since 2015, how we understand the ‘habitable zone’ has changed a lot (mainly because we have so much more data) and Kepler-442b is still where it was. A worse in the rankings, but giving everything.

After all, unless someone sends us a message and says “hey Earthlings, we found your Voyager, stop littering space”, we’re not going to find life quickly. We still have a lot to develop, a lot to know, a lot to imagine. That’s the interesting part and the tidbits that make headlines (no matter how spectacular they sound) are, as I said at the beginning, the most boring part.

Image | Mark A Garlick

In just a handful of years, what used to sound like something exciting (“discovering exoplanets”, “finding potentially habitable planets”) has…

In just a handful of years, what used to sound like something exciting (“discovering exoplanets”, “finding potentially habitable planets”) has…

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