Please say more. What was this expected and how does it support the carbon-based hypothesis?
There are only a few chemistries that could even support life. Carbon is the one we know the most about, and also one that we find the most evidence for getting to that complex of chemistry in the real universe. Nobody knows of course, but odds seem good if there is other life out there is it carbon based. (nobody really can know either - the universe is so far away we can't really detect details very well)
Not a thumb between them.
No thumbs.
Opposable thumbs are not a guarantee. Nor are tree-dwelling lifeforms, nor trees, nor thumbs, nor digits, nor four limbs. For all we know, intelligent life elsewhere might better resemble intelligent octopi using alkaline metals as their first rudimentary energy source as we did with fire.
Hell, it took 2 billion years to get to single celled eukaryotes on earth. But the earth was teaming with prokaryotes the whole time, two entire separate branches of them, too, and they seem to have sprung into existence almost as soon as the earth cooled enough.
There's still a lot more of them in terms of total weight than animals and protists. A lot.
I do think that developing more sophisticated tools under water is difficult. Once you have plants on land, taller “trees” are very probable, because they are competing for light. Once you have trees, it’s likely that animals will climb then for safety or food. Once they climb, they will likely develop better gripping, etc…
I guess another way to look at this is that life on Earth is not special (although it is still an insanely amazing occurrence).
Land mostly requires that your planet doesn't have too much water. Plate tectonics helps, but I'm not sure it's required.
They evolved here. The whole question is how much their existence depends on Earth's specific environment, genetics, etc.
Carbon is one of a few elements to be able to easily bind to other elements including itself and able to form long and complex chains. Silicon is another that can form long, complex chains.
https://www.sciencealert.com/lack-of-phosphorus-in-universe-...
I don't think this is an accurate reading of that article. See forex https://arxiv.org/abs/1704.08282 whose abstract reads in part:
> We also found average [P/Si] = 0.02 ± 0.07 and [P/S] = 0.15 ± 0.15 for our sample, showing no significant deviations from the solar ratios for [P/Si] and [P/S] ratios.
Quoting from the introduction I find:
Phosphorus abundances have been derived in planetary nebulae .... and in damped Lyman alpha systems using ionized phosphorus lines ... Anomalously high phosphorus abundances have been measured using optical phosphorus features in blue horizontal branch stars ....
Molecular forms of phosphorus, such as PO, PN, and CP, have been detected and used to understand phosphorus chemistry in the interstellar medium ...
or example, phosphorus molecules have been detected in the interstellar medium ... and in star forming regions ... Phosphorus molecules have also been found in the circumstellar envelopes of evolved stars (... Finally, the diffuse interstellar medium has been measured using P II lines....