A new study has raised the possibility that advanced versions of T Rex and other dinosaurs, monstrous creatures with the intelligence and cunning of humans, may be the life forms that evolved on other planets.
In the report, Ronald Breslow discusses the century-old mystery of why the building blocks of terrestrial amino acids, sugars, and the genetic materials DNA and RNA exist mainly in one orientation or shape.
There are two possible orientations, left and right, which mirror each other in the same way as hands. This is known as "chirality".
In order for life to arise, proteins, for instance, must contain only one chiral form of amino acids, left or right. With the exception of a few bacteria, amino acids in all life on earth have the left-handed orientation. Most sugars have a right-handed orientation.
Breslow described evidence supporting the idea that the unusual amino acids carried to a lifeless Earth by meteorites about 4 billion years ago set the pattern for normal amino acids with the L-geometry, the kind in terrestrial proteins, and how those could lead to D-sugars of the kind in DNA.
"Of course, showing that it could have happened this way is not the same as showing that it did," Breslow said.
"An implication from this work is that elsewhere in the universe, there could be life forms based on D-amino acids and L-sugars.
Such life forms could well be advanced versions of dinosaurs.
We would be better off not meeting them," Breslow added.