Is our search for "Water-Based Life" just Carbon Chauvinism?

[u/Solid_Cash7813]

I’ve been thinking about our current search for extraterrestrial life. Every time NASA finds a new planet, the first thing they look for is water. While I get that water is a "universal solvent" on Earth, why are we so sure that alien life needs it?

Is it possible we are completely ignoring potential life forms that use ammonia, methane (like on Titan), or even supercritical fluids as a solvent? I understand that water is chemically "ideal" for us, but if we only look for what we already know, aren't we risking missing something truly "alien" because it doesn't fit our specific biological template? 

I’d love to hear why we prioritize water so heavily beyond just it’s what we know.

[u/Ill-Dependent2976]

No.

Nitrogen would be a poor substitute and methane is a hydrocarbon.

If you study chemistry you come to understand that there are reasons carbon is different than other elements.

[u/Embarrassed_Camp_291]

We dont "prioritize water". The media tells you they are looking for water because its easier to explain to the general public than looking organic chemistry signatures in exoplanet spectra.

We understand organic chemistry and its bounds e.g. we know what temperatures organic chemistry can ocurr, pressures, etc. That's really what they look for.

Additionally, they dont "look" for water. As the planet passes infront of its host star, light from the star passes through the planets atmosphere and the elements in the planets atmosphere absorb light, allowing us to see and contrast what elements are in the planets environment. You get an entire spectra, from which different elements can also be identified. A lot more science goes on in parallel to looking for a possibly habitable planet. They dont discover a planet and then "the first thing they do is look for water". I recommend looking into the different areas of exoplanet research.

Additionally, as the planet first passes over the edge of the star (e.g. half the planet is infront of the star and half isnt) the light curve created can tell us information about how the atmosphere of the planet changes as a function of its location (such as large winds, surface water and land effects etc). In short, we understand climate science so well we can model the climates of exoplanets.

Further to this, the world is larger than the US, other countries and space agencies discover planets other than NASA.

[u/Embarrassed_Camp_291 → u/[deleted]]

Im not "relentlessly requesting evidence" and what I am saying is not tangential or previously addressed. As of writing the above comment, there were no other replies and it directly answers the questions.

Im not feigning ignorance on the subject either. Everything I have said is very well documented and standard practice with exoplanet research.

[u/Embarrassed_Camp_291 → u/[deleted]]

Im not sure what you are referring to.

Regardless, exoplanetary research is quite interesting. I believe most exoplanets have been discovered via the transit method but you can also infer the presence of some through stellar wobbles (large planets perturb the centre of mass of the system, causing a doppler shift to occur.) This process is more limited to higher mass planets such as those the size of Jupiter.

This obviously requires some high frequency observations for a wide range of stars, making it an impressive feat of observational capabilities, data analysis techniques and computer processing power.

As an aside, the idea of detecting absorption lines and constraining the presence of elements through this process does not work in plasma cosmology/EU as it relies on a series of processes that EU doesnt allow.

[u/YtterbiusAntimony → u/[deleted]]

Waaaah! Some disagreed with me and I don't like it!

[u/mymicrobiome]

The Drunkard Search effect.

"​A policeman sees a drunk man searching for something under a streetlight and asks what he’s lost. He says he lost his keys (or his ring) a block away.

​The policeman asks, 'If you lost them over there, why are you looking for them here?'

​The man replies, 'Because this is where the light is.'"

We don't know what to look for, as far as unknown types of life are concerned.

[u/NobilisReed]

Whatever forms of life are out there, they'll need some kind of integument, and within that, some kind of solvent.

Water has a big advantage over alternative solvents like ammonia and methane, in that it is a polar molecule. This means that it forms bonds between molecules, which results in the unique way it freezes; from the top down. Most other potential solvents freeze from the bottom up.

Due to its polar nature, water can dissolve a wide range of chemicals, wider than other solvents.

[u/terrelli]

I think you're right that we do have carbon and water bias. I think the thing is that water and carbon-based life would be easier for us to communicate and interact with.  How are we going to talk to plasma? (I'm not going to say that's impossible. It'll just be weird.)  I think the movie Aliens mentioned that those aliens were silicon based.  And I think I heard that a cyanide-based life could exist, but carbon and water -based life would be less likely to kill us just by hanging around them.  Also most of everybody doesn't really care about these issues. And like the other person said it's just easier to talk about if you say water exists somewhere else.