NASA has found tryptophan in the asteroid Bennu, yes, the tryptophan that in our body serves to build proteins (and serves to produce serotonin, the hormone of happiness), and it is the first time that this compound appears in extraterrestrial material, in an asteroid!!
The samples, collected by the OSIRIS-REx mission and brought to Earth in a capsule that landed in the Utah desert, did not only contain this amino acid, the total is 14 amino acids, five nucleobases and chemical signals that point to Bennu having had liquid water at some point in its history. Aha, water!!! Well, for being a rock that floats in space, it has quite a lot of information that interests us, right? And what if life did not start on Earth from zero, but arrived “in pieces” from outside transported by asteroids? And we are not talking about esoteric theory, but pure chemistry!!
Bennu
The analysis was published in PNAS, and it was done with techniques that break down the samples to try to identify molecules and be able to study them in depth. The surprise was that nobody expected there to be tryptophan in an asteroid because it had never been seen before in extraterrestrial fragments.
That such a complex amino acid exists outside Earth suggests that the chemistry of space is not as rudimentary as our scientists imagine, and also that we are one step closer to knowing where we come from and what is out there.
And the theory that out there there might also be “sophisticated structures” (living beings, like us) no longer seems like an illuminati theory, but something much more tangible.
Why so much fuss about tryptophan?
Because we are not talking about just any molecule, tryptophan is one of the essential amino acids of living beings and without it we could not fabricate proteins (which we need for absolutely everything). We also could not regulate emotions, sleep or appetite the way we do today.
Finding it in an asteroid means that the chemistry to build life is not exclusive to Earth and that somewhere in space, without atmosphere, without oceans and without plants, it was generated anyway.
Careful, that does not imply that there were living beings on Bennu, but it does suggest that the universe has more creative capacity. And we want to find it, right?
An asteroid that lived things
The study also revealed that in Bennu there are zones with more organic compounds than others, which suggests that the asteroid had liquid water at different moments, even if it was in minimal quantities.
And that, for chemists, is like turning on a giant light, water + organic molecules + time = conditions for interesting things to happen.
Another curious detail is that the amino acids were present in equal parts between their “left” and “right” version, and on Earth we only use the “left” version. And this means that the biological preference for one type arose here, not outside.
And what if life arrived riding on an asteroid?
This idea is very bold, and it has for many years been the object of mockery by many scientists towards those who like slightly crazier theories, but now that “intense bombardment” that the Earth suffered could have come with water, salts and organic molecules, and that here the perfect conditions were given for life to form.
And now?
Scientists have to continue investigating if there is tryptophan with other techniques, they will see how it is distributed inside the asteroid to know how much there is and how to continue investigating.
We are not solving the mystery of the origin of life, there is still time for that and probably, we will not even get to discover it, but now our scientists have other questions to ask themselves and begin to debate how many things happened before life arose on our planet.