streetlight perhaps a hundred yards to his left. Power was intermittent in Gaza and electricity cables were often run directly down the tunnels by insurgents, using either the grid or generators to supply light to the depths. This tunnel would most likely pass close by the streetlight, an easy point at which to tap into the electricity supply. From there, he suspected that a row of buildings on the opposite side of the street provided a likely termination point, an escape route for Hamas fighters fleeing an Israeli assault.
Rafael pocketed his blade and moved around to the ladder, carefully testing its strength before lowering himself into the darkness.
The remains Lucy found were similar to humans,” Rachel said. “You think that life on other planets is like life on Earth?”
Hassim Khan shook his head.
“That’s unlikely. Life on other planets will endure differing environments. If a planet orbiting another star was more massive than Earth, then its gravity would be correspondingly higher, resulting in species of a more muscular build to counter their increased weight on such a planet. That could match the physicality of the species Lucy found.”
“But it looked almost human to me,” Ethan said, “just a lot bigger. Surely that can’t be possible on an entirely different planet?”
“Evolution often follows certain paths,” Hassim explained. “There are facets of biological species that often appear as a result of natural selection, especially in predatory species. Limbs, eyes, ears, grasping hands and so on appear frequently in the fossil record. There is no reason to think that this would not occur on other planets too.”
Ethan sat in thought for a moment.
“Do you think that genetic material could be extracted from Lucy’s find?”
“Almost certainly.” Hassim nodded. “Researchers have successfully extracted intact blood cells from a Tyrannosaurus rex bone some sixty-five million years old. The remains that Lucy found were only seven thousand years old. I wouldn’t be surprised if they were able to recover organic material from it, maybe even intact DNA.”
“Which would confirm the idea of life forming on a universal theme,” Ethan guessed.
Hassim smiled.
“The origin of life among the stars as a universal and not a local event,” Hassim agreed. “It’s known as panspermia.”
“You mean that we didn’t evolve on Earth?” Rachel stammered.
“Oh, we evolved here all right,” Hassim corrected. “But the very things we are made of did not, and that may include life in all of its self-replicating glory. It has been known for some time that when giant stars die in supernova explosions, the material they release in the cooling conditions contain carbon grains, and that particles of other chemical elements attach themselves to the tiny grains and react enthusiastically with each other. These carbon grains were given a name: stardust.”
“Grains?” Ethan asked. “Like sand?”
“Much smaller,” Hassim said. “Spectroscopic studies of these star-remnant molecular clouds have found there the presence of methanimine, formaldehyde, formic acid, amine groups, and long-chain hydrocarbons caught within their veils. These are the building blocks of life: methanimine is an ingredient in amino acids; formic acid is the chemical that insects use as venom and is also the stinging ingredient in nettles. Both are polyatomic organic molecules that combine to form the amino acid glycine, which has since been seen in molecular clouds in deep space and found in comets by NASA in 2009, and amino acids are one step away from life itself.”
“And that’s without planets forming?” Rachel asked.
“Yes,” Hassim said. “Ultraviolet radiation bathes the clouds, heat from other nearby stars warms them, and all manner of chemical reactions occur. Frozen water, methanol, and ammonia rapidly form around the grains as the heat from the supernova fades. Trapped within these tiny cores the elements react and produce various polyatomic molecules. Experiments carried out in 2001 at NASA’s Ames Research Center confirmed these processes, when silicate grains covered in this kind of material were chilled to the temperature of deep space and suspended in ultraviolet light. When the organic compounds produced were immersed in water, membranous cell structures appeared spontaneously, as they may well have done on the young Earth: life, without supernatural intervention. All life on Earth is based on cells such as these, biological material encased in a membrane.”
“It all fits together,” Ethan said, genuinely amazed.
“That’s what science does. In 2002,” Hassim went on without missing a beat, “further experiments conducted with water, methanol, ammonia, and hydrogen cyanide found in molecular clouds discovered that three amino acids called glycine, serine, and alanine arose spontaneously within the containers. In another similar experiment, no