I saw a boron-based life form in a sci-fi show and it made me curious about how that works. I did some reading on it, and all I see is around the oxidation states and the ability to bond with atoms.
I vaguely grasp these concepts, but don’t get why, if it is possible for boron to build life, why can’t we/haven’t we done it?
In: 0
Carbon is better as a base for life than anything we know of, even boron or silicon. More than that, we have examples all around us to learn from.
And yet we cannot yet build carbon-based life from scratch. So it stands to reason that boron will take longer.
A lot of our definitions of “life” are really narrow to the STP and composition of the earth and it’s atmosphere. Things that bond less durably than carbon would need colder environments to be stable. Boron life form would be something you’d see in weird atmospheres and low temps probably. Maybe a moon or planet near a brown dwarf
Carbon has two major things that make it more versatile than other atoms. It is most stable when it has 4 bonds and it makes bonds with hydrogen that essentially have no charge. Boron is… weird. It wants to make 3 or 5 bonds but either one makes it unhappy and results in weird charge distributions. Without getting too deep into chemistry. Boron is the hardest atom to make happy stable bonds, it’s both too weak and too strong, and too positive or negative to make long chains based on Boron.
Carbon is best, then Silicon, then Arsenic, then maybe boron or germanium. Are candidates for life to be based on but in abundance carbon is always going to be the first to look for.
The way I saw this sort of question explained best (it was about silicon, but same answer) is this:
Life as we know it works because there are molecules that can encode information, store it, copy it, build new molecules off of it and then, most importantly, MODIFY it (aka evolution).
This is important, because without stored information, you have just your standard chemistry.
To have these sort of molecules, you have to have atoms that like to interact with themselves strongly enough to form a skeleton of that molecule, but not so strongly that it’s brittle and can’t be rearranged.
It also has to have enough bods to allow attaching other atoms, so that more complex molecules can be form. A pure monoatomic crystal doesn’t do chemistry.
This skeleton’s form also has to enable of encoding and decoding of information. Here again, a 3 dimensional crystal lattice is too closed for chemistry. So you need something like chains or sheets. It would be difficult to enforce reading off of a surface with chemistry like we do with an HDD. Chemistry is too random. Chains seems like the only viable choice to actually encode something, because there’s literally only one direction. It enforces structure.
There’s only two atoms that we know of which form chains. Carbon and Silicon.
Out of the two, carbon chains are more flexible and form almost spontaneously, while silicon loves forming either a crystal or reacting with oxygen to form silicon dioxide, so it’s more difficult for it to form chains. And when it does, they’re much more fragile than carbon ones, which means they break apart too easily. Meanwhile carbon chains are really durable, but not so much to prevent SOME rearranging.
Basically, if you wanted to purposefully design self-replicating, information carrying molecules, carbon would be the no-brainer choice, with silicon a fairly distant second.
So while it’s remarkable that life can exist, it was going to be made out of carbon, because chemistry is blind and carbois the exponentially more likely one to work, so basically probability wins.
Latest Answers