If the universe weren't filled with unimaginably unlikely coincidences and anomalies, life--here or anywhere else--could not exist, Higgins Professor of Biology Emeritus George Wald said to several hundred Harvard students and Cambridge residents in the Science Center last Wednesday.

His talk, called "Life and Mind in the Universe," was one of the Science Center's monthly lectures specifically desiged for nonscientists.

The Nobel Prize-winning eye researcher began by describing how our universe is probably "permeated with life."

One out of every hundred stars might host a planet capable of supporting life and our own galaxy could contain a billion such stars.

Multiply that by one hundred billion galaxies, and the Earth seems less overpopulated, Wald said.

But "if any of the properties of our universe were different, that life that now - seems so prevalent would become impossible."

Atomic warfare

Wald said that once during a conversation with Albert Einstein, the great physicist suddenly piped, "Why do you think all the natural amino acids are lefthanded.... You know, I always wondered why the electron came out negative; it must have won the fight."

The "fight" occurred in the early universe between matter and antimatter, which annihilate each other into energy on contact.

Theoretically, the universe should have contained equal amounts of both--matter and antimatter which would have wiped each other out completely, leaving nothing but energy.

The only reason we exist is that for every 100 billion primordial particles, there was one more particle of matter than antimatter.

"The residue--that one one-billionth--that's our universe," Wald said.

Another lucky break is that protons and neutrons (both of which are nucleons) are nearly 2000 times heavier than electrons.

Consequently, an atomic nucleus stays relatively stili compared to the electrons whipping around it; this makes atoms stable.

"If nucleons and electrons were closer in mass, we could not have such structures as molecules. Under these circumstances, there could be no life," Wald added.