Imagine an alien world ruled by "advanced dinosaurs" as smart as humans—maybe even smarter.
Science fiction? Not necessarily, says the author of a provocative new study whose title--“Evidence for the Likely Origin of Homochirality in Amino Acids”—gives no hint of any worrisome extraterrestrial implications.
Published in the March 25 issue of the "Journal of the American Chemical Society," the study addresses the chemistry of amino acids here on Earth. But study author Dr. Ronald Breslow, a professor of chemistry at Columbia University in New York City, said in a written statement the work suggests that if life forms do exist on other planets, they “could well be advanced versions of dinosaurs."
It’s long been known that certain molecules, including DNA and amino acids, exist in two mirror-image forms—a phenomenon known as chirality. And with few exceptions, the amino acids that make up the proteins in life on Earth exist only in the L (left-handed) form. The question is how did this “homochirality” come to be?
Some scientists have speculated that the amino acids that predominate on Earth came to our planet via meteorites four billion years ago. And if that’s what happened on Earth, Dr. Breslow said in the statement, it’s possible that life that might exist on other planets could be based on D amino acids.
From there, Breslow makes the jump to advanced dinosaurs. But why might extraterrestrial life be in that form? “Because mammals survived and became us only because the dinosaurs were wiped out by an asteroid, so on a planet similar to ours without the asteroid collision it is unlikely that human types would be there, more probably advanced lizards (dinosaurs),” Dr. Breslow told The Huffington Post in an email.
Not everyone is convinced.
“Animal-like creatures that might evolve on other worlds will not be and cannot be dinosaurs,” Dr. Paul "PZ" Myers, associate professor of biology at the University of Minnesota Morris, wrote on his blog. “There is no reason to imaging that a saurian-mammalian transition is anything but a particular quirk of our particular planet’s evolutionary history—it is not a universal.” Dr. Myers termed the paper “badly written nonsense.”
Of course, if advanced dinosaurs could exist on other planets, we might want to rethink our efforts to make contact with extraterrestrial life. Says Breslow of the brainy dinos he imagines, “I just warn that they might well see us as food.”
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This heavily-armored predator had the second most powerful bite of any fish.
The hornless rhinoceros-like creatures of this genus were the largest land mammals of all time.
Giant ground sloths of this genus were about the size of today's elephants. The megatherium only went extinct around 10,000 years ago (right around the time when humans started farming), and smaller relatives may have survived as late as the 16th century!
Richard Owen, director of London's Museum of Natural History, stands next to the largest of all moa. Moa, which originated in New Zealand, were flightless, and some were even wingless.
The Argentavis magnificens, an early relative of the Andean Condor, was the largest flying bird ever discovered.
These creatures, the largest marsupials that ever lived, roamed Australia. Some scientists have suggested that stories of the supernatural 'bunyip' creature in Aboriginal folklore could be based on diprotodonts.
These distant relatives of modern elephants had an imposing appearance, with strange, downward-curving tusks and heights of up to 16 feet at the shoulder.
Leedsichthys problematicus & Liopleurodon rossicus
The fearsome Liopleuredon, right, had a jaw nearly ten feet long. The Leedsichthys, left, was a bony fish that may have been even larger than it looked; some estimates put its maximum length at 53 feet. <strong>Correction</strong>: <em>An earlier version of this slide had the positions of the Liopleuredon and Leedsichthys reversed</em>.