The country may be swirling down the drain, but at least we’ve got some interesting news from outer space…even if Nature chose a really misleading title for their article, Asteroid fragments upend theory of how life on Earth bloomed. Scientists are analyzing the samples returned from a probe sent to the asteroid Bennu. They’ve found all 5 nucleic acid bases, and 14 of our familiar 20 amino acids, which is not surprising. We’ve found those in meteorites here on Earth.
Furthermore, the molecules are found in roughly equal numbers of right- vs. left-handed enantiomers, which is also not surprising. It’s biological synthesis that favors one handedness over the other; this is exactly what we’d expect of molecules built via inorganic synthesis in a lifeless rock. We might have to upend a few theories if these molecules were found to have been assembled by living organisms that had been living on an ancient space rock. But they weren’t, so nobody is rewriting any biology textbooks.
I did not expect this, though:
In an accompanying paper published in Nature today, other researchers report that the material from Bennu is also rich in salts created billions of years ago, probably when watery ponds on Bennu’s parent asteroid evaporated and left behind a crust of minerals. Although no signs of life were spotted on Bennu, those salty ponds would have been a good environment to foster the chemistry that could lead to it.
Salty ponds? On space rocks? I’d like to know more about that, although note that there’s no evidence that life evolved in puddles on asteroids. It’s still cool to imagine briny ponds on distant moons and planetoids.