Thread by @People_Of_Space

Now that I introduced you to how science communication can go wrong, let's see why it goes off course sometimes. There are multiple factors, but I think the greatest pitfall in the translation from scientists to journalists and then the public is: The Habitable Zone. A thread:

Because the Habitable Zone is, in fact, NOT what is shown in the GIF before. It doesn't encompass ALL the things that make a planet "liveable" for humans. What it means is that the planet is situated "right" in relation to its host star to have liquid water, in a crude sense.

As you can see by the quotation marks, it's more complicated than that. @ravi_kopparapu published a paper in 2014, taking into account many more factors, like CO2 and H2O dominated atmospheres, planetary mass, stellar type, etc.

Look at #Kepler186f in this graphic from @NASA for example. The systems are to scale. And since the host star Kepler-186 irradiates less than our Sun, the Habitable Zone is much closer to its star than it is for us. Planet f (about the same distance as Mercury) is thus in its HZ.

Here is a graphic taking into account the more sophisticated version of the Hab. Zone from @PlanetaryHabLab at the @NAICobservatory. Here you can see where the different exoplanets I talked about earlier sit, and how suited or not suited they are for habitability.

So where does the confusion start? Being somewhere in the Habitable Zone doesn't mean "let's move there", it means, potentially life could survive here. It means 'maybe' there is water in liquid form, 'probably' the planet is the right size.

Any talk of an Earth 2.0 is widely exaggerated. Both Mars and Venus fall at the borders of the HZ here and who would want to move there? No one. Some planets in this sample of Super-Earths have masses 5-10 times the mass of Earth, can you imagine?

So, although the name "Habitable Zone" suggests it's like home, it just means, "not instant death while still in a spacesuit". It doesn't mean a breathable atmosphere. It doesn't mean alien life. And it for sure doesn't mean this is our plan B to get off our own blue marble.

So whenever we as scientists talk about the Habitable Zone, we have to take into account what this name insinuates, at what it actually means. Or we are right back in the next round of news articles about a "Planet B", when it might be another Venus.

And don't forget: These planets are incredibly far away. The closest, #ProximaCentauri_b is 4 lightyears away. #Voyager I, who was sent out into space in 1977, has so far only made it out to 0.002 lightyears. Human space flight won't make it to our closest neighbour anytime soon.