4 ms·

This doesn't prove anything, but it's interesting to consider at least: if you look at the list of the most common elements in the Milky Way[1], 7 of the top 10

by Cyphase 10y ago

This doesn't prove anything, but it's interesting to consider at least: if you look at the list of the most common elements in the Milky Way[1], 7 of the top 10 are essential for life on Earth: Hydrogen (#1), Oxygen (#3), Carbon (#4), Iron (#6), Nitrogen (#7), Magnesium (#9), and Sulfur (#10). Silicon (#8) is also pretty much essential. The other 2 elements in the top 10, Helium (#2) and Neon (#5), are noble gases with low chemical reactivity. So, what could that mean? If you claim that those elements (or at least a subset) are essential for any kind of life, then by the anthropic principle, it's not surprising to see the distribution that we see in our home galaxy. Alternatively, you could claim that life can evolve with all sorts of combinations of elements, but that it makes sense that it would evolve to use the most common elements in any given area of the Universe. Either way, it seems like the fact that the life we know uses the most common elements in the galaxy is a good reason to expect non-Earth-based Milky Way life to be similar. This is just a thought I've had in the past; I haven't done a whole ton of research into this correlation. And of course, there's a whole other set of arguments involving the chemical properties of elements, which I'm just skipping over in this comment. [1] https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Abundance_of_elements_in_the_Universe https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elem... EDIT FOR CLARITY: The sentence mentioning the anthropic principle used to read: "By the anthropic principle, you might say that those elements (or at least a subset) are essential for any kind of life, and given that life exists on Earth, it's not surprising to see the distribution that we see in our home galaxy."

blauditore 10y ago
I think the anthropic principle should only be applied the other way around: We're here due to this environment, so other places with similar environments might harbor life too. But this doesn't say anything about whether different environments may enable life too. The second claim seems much more sense to me (like horses vs. zebras). However, actively searching for organic compounds in search of life would lead to circular reasoning. After all, organic life is probably the easiest one to search for because it's the only one we know so far.
- Cyphase 10y ago
  You're right about the anthropic principle; I wasn't clear. I've edited that sentence to clarify what I meant. As for none of this saying "anything about whether different environments may enable life", I agree; as I said at the beginning of the comment, this doesn't prove anything. Anyway, I was more talking about the likelihood of similar-to-Earth life as opposed to whether other types of life are possible at all.

by Cyphase 10y ago

blauditore 10y ago

I think the anthropic principle should only be applied the other way around: We're here due to this environment, so other places with similar environments might harbor life too. But this doesn't say anything about whether different environments may enable life too. The second claim seems much more sense to me (like horses vs. zebras). However, actively searching for organic compounds in search of life would lead to circular reasoning. After all, organic life is probably the easiest one to search for because it's the only one we know so far.

Cyphase 10y ago
You're right about the anthropic principle; I wasn't clear. I've edited that sentence to clarify what I meant. As for none of this saying "anything about whether different environments may enable life", I agree; as I said at the beginning of the comment, this doesn't prove anything. Anyway, I was more talking about the likelihood of similar-to-Earth life as opposed to whether other types of life are possible at all.