The threat of intelligent space dinosaurs

Chirality is an interesting concept. The best way to explain it quickly is an analogy to being left-handed or right-handed. Molecules don't have hands, but they do have an inherent orientation that can be compared to having a dominant hand that you do most of your work with. Sugars are mostly right-handed. Amino acids: Left-handed.

But here's where things get weird: It doesn't have to be that way. In fact, given the randomness and chance through which evolution works, it would make more sense for there to be a lot more diversity in orientation.

All of this backstory is important so that I can tell you about the most hilarious non sequitur I've encountered in 2012.

Chemist Ronald Breslow has a new paper out in the Journal of the American Chemical Society, where he talks about why chirality might be the way it is. For the most part, his ideas are not unreasonable ones. Breslow thinks that life on Earth—and we're talking about life in its simplest forms, like molecules, not actual creatures—could have been "seeded" by material that fell to the planet on an asteroid. The idea is that, if the building blocks of life came from one place—a meteor fall—rather than arising and adapting here, it could explain why there's not the diversity of molecular "handedness" that we might otherwise expect to see.

In fact, in related news, there's another paper out suggesting that Earth could have paid that gift of life forward, with potentially microbe-and-molecule-laden rocks from here traveling far into interstellar space.

What makes Breslow's paper unique is the odd, brief, speculative tangent he gets into at the very end, a tangent which lead to me receiving a press release titled, "Could Advanced Dinosaurs Rule Other Planets?"

An
implication 
from
 this 
work 
is 
that
 elsewhere 
in
 the
 universe
 there
could be 
life
 forms
 based 
on 
D 
amino 
acids
 and 
L 
sugars,
 depending 
on 
the 
chirality
 of
circular
 polarized
 light
 in 
that 
sector
 of 
the 
universe
 or
 whatever 
other 
process 
operated 
to
 favor
 the
 L 
α‐methyl 
amino
 acids
 in 
the
 meteorites 
that 
have 
landed 
on
Earth. 

Such
 life
 forms
 could
 well
 be
 advanced
 versions
 of
 dinosaurs,
 if
 mammals
 did
 not
 have the 
good 
fortune 
to 
have
 the 
dinosaurs 
wiped 
out
 by 
an 
asteroidal
 collision,
as
on
 Earth. 
We
 would 
be
 better 
off 
not 
meeting 
them.

I suppose it's rather hard to argue with the basic thesis that we'd be better off not meeting a hyper-intelligent T. Rex. But at Dinosaur Tracking, Brian Switek attempts to explain why it's maybe not a great idea for chemists to randomly start pontificating on paleontology. In particular, the "rule" of the dinosaurs was not inevitable and was not dependent on the outcome of a single asteroid collision.

Prior to 250 million years ago, the synapsids—our ancestors and relatives—were the dominant creatures on land. But the apocalyptic extinction at the end of the Permian Period eliminated most synapsid lineages, in addition to many other forms of life. This clearing of the ecological slate is what allowed a different group of creatures to proliferate. Early archosaurs, or “ruling reptiles,” included the archaic forerunners of crocodiles, pterosaurs and dinosaurs, in addition to various groups now extinct, and these creatures dominated the Triassic.

Despite what has been traditionally told, though, the dinosaurian branch of the greater archosaur family tree didn’t immediately out-compete its neighbors. Eoraptor and Herrerasaurus were not the Triassic terrors they were cast as during the mid-1990s. For the most part, Triassic dinosaurs were small, rare, marginal parts of the ecosystems they inhabited. It was only after another mass extinction at the end of the Triassic, around 200 million years ago, that the competitors of early dinosaurs were removed and the reign of the dinosaurs truly began.