The Search for Habitable Planets: “Life is a Natural Planetary Phenomenon”

6a00d8341bf7f753ef01287716b2ef970c.jpg “Columbus forced everyone to rethink, redesign and rebuild their world view.That’s what we’re doing here. To put it in 15th-century terms, we’ve reached the Canary Islands."

Dimitar Sasselov, professor of astrophysics and director of Harvard University’s Origins of Life Initiative Project. 

“It’s feasible that we’ll meet other sentient life forms and conduct commerce with them,” Sasselov says, pointing toward the exo planet he discovered on Nov. 12, 2002, he unofficially named Sheila, after his wife in Harvard’s astronomy-department laboratory. “We don’t now have the technology to physically travel outside our solar system for such an exchange to take place, but we are like Columbus centuries ago, learning fast how to get somewhere few think possible.”

Sasselov believes that life is probably common in the universe. He said that he believes life is a natural “planetary phenomenon” that occurs easily on planets with the right conditions. “It takes a long time to do this,” Sasselov has said at a recent Harvard conference. “It may be that we are the first generation in this galaxy.”

Though it may be hard to think of it this way, at roughly 14 billion years old, the universe is quite young, he said. The heavy elements that make up planets like Earth were not available in the early universe; instead, they are formed by the stars. Enough of these materials were available to begin forming rocky planets like Earth just 7 billion or 8 billion years ago. When one considers that it took nearly 4 billion years for intelligent life to evolve on Earth, it would perhaps not be surprising if intelligence is still rare.

Sasselov expects the Kepler Spacecraft to rapidly increase thenumber of  planets already found orbiting other stars. Unanalyzed Kelper data may reveal numerous “super Earths” or planets from Earth-size to just over twice Earth’s size that Sasselov expects would have the stability and conditions that would allow life to develop.

If life did develop elsewhere, added Andrew Knoll, the Fisher Professor of Natural History at the Harvard conference, used the lessons of planet Earth to give an idea of what it might take to develop intelligence.

"Of the three major groupings of life: bacteria, archaea, and eukaryotes," he said, "only the eukaryotes developed complex life. And even among the myriad kinds of eukaryotes, complex life arose in just a few places: animals, plants, fungi, and red and brown algae. Knoll said he believes that the rise of mobility, oxygen levels, and predation, together with its need for sophisticated sensory systems, coordinated activity, and a brain, provided the first steps toward intelligence."

It has only been during the past century that we have had the technological capacity to communicate off Earth, Knoll said. And, though Kepler may advance the search for Earth-like planets, it won’t tell us whether there’s life there, or whether there has been life there in the past.

Casey Kazan via


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