Late last year a team of European astronomers announced that they had found a planet located in the nearest star system to our sun, Alpha Centauri.
At 4.6 light-years away, it’s just a stone’s throw on the cosmic yardstick. The system is reachable within a human lifetime at velocities of one-tenth the speed of light. We don’t need warp drive to magically travel there at superluminal speed.
But now another team of astronomers says they don’t see the telltale signature of the planet in their measurements. They too looked for any small wobble in the companion star Alpha Centauri B that would be induced by the gravitational tug of an unseen world, but didn’t see a signature.
The small planet, if real, is unobservable because it is too close to the star and only one-ten billionth as bright as the star.
These kind of debates over the reproducibility of an observation are the bedrock of science inquiry. They are especially common for planet searches that have to tease out an extraordinarily faint signal from the “noise” of a star’s own idiosyncrasies — or those of the detector on the telescope.
“Hold Off on the Alpha Centauri Trip,” The New York Times announced in its story last week about the doubtful planet.
But this question really misses the point. There has been a paradigm shift from a decade ago when astronomers wondered how many other stars had planets. The question today is where are the planets located around a star? How big are they, and what is the evolution of the planetary system?
The impressive planet inventory take by NASA’s Kepler space observatory, combined with other research, has taken us down the road to concluding that, on average, every star in the Milky Way galaxy has at least one planet. What’s more, Earth-sized planets are far more common than giant Jupiters.
If we ever convinced ourselves that Alpha Centauri doesn’t have any planets, that would indeed be quite a shocker and worthy of front-page news in the New York Times.
Even if the Alpha Centauri B planet doesn’t exist, there is very little doubt that other planets will be discovered there. It’s only a matter of time. Perhaps all three members of the triple system of two sunlike stars and a diminutive red dwarf star possess planets.
So I will boldly predict that the Alpha Centauri system has a number of planets and at least one should be habitable. The details of this system will be exciting and extraordinary in the same way European explorers marveled at the New World.
The system is so old that, under the right planetary conditions, Darwinian evolution has kicked in and there is an alien world that is covered with an extraterrestrial Serengeti of multi-celled creatures that make Michael Crichton’s Jurassic Park look like a petting zoo.
Could intelligent life be there too? Unfortunately, in a lousy coincidence, the star system is too far south to be observed by the powerful Arecibo radio antenna in Puerto Rico, or the new Allen Telescope Array in northern California, that can easily look for any artificial radio transmissions.
Nevertheless, It’s not too early to think about the a millennium-long project to visit and colonize the star system. I cannot imagine a bolder step for the evolution of mankind. The project will cost untold trillions of dollars spent across many generations. But it will establish us as an interstellar species, that is for all practical purposes, immortal. This would be an evolutionary step as profound as when Earth’s first sea creatures ventured onto land.
As always, the devil’s in the details. It would be unethical to take over an inhabited planet — even if it didn’t have intelligent life. Even if our distant descendants took a cold-hearted Interstellar Manifest Destiny attitude, colonists would have to deal with alien microbes and some pretty fierce predatory creatures I imagine. (I’m reminded of the hellish organisms in the 2007 film version of Stephen King’s, The Mist.)
But uninhibited planets or moons in the Alpha Centauri system could be terraformed. Pre-born Earth colonists might be genetically engineered to adapt to the planned alien environments.
What’s more, presuming there’s an asteroid belt, artificial worlds could be constructed. We might co-exist inside the system with its indigenous life. Astro-paleontologists and astrobiologists might cautiously visit the inhabited planets to study life’s evolution across a completely independent track from Earth’s. Per “Star Trek”s Prime Directive, we would avoid contact with intelligent life for fear of derailing their cultural evolution.
Now imagine a technological civilization does live at Alpha Centauri. In the absence of any SETI transmission from Earth, the Centaurians assume we are a technologically immature species. They proceed to colonize our asteroid belt. This scenario would explain the plethora of UFO sightings and even those “close encounters” with extraterrestrials. That is, if UFOs were actually real. In reality we would have picked up circumstantial evidence for the presence of a colonizing alien civilization – anomalous heat plumes in the asteroid belt, asteroid mining, or unusual electromagnetic signatures.
Let’s just hope that if Centaurians exist, they don’t plan a preemptive invasion out of fear we might be making interstellar conquest plans.
Image credit: PHL, UPR Arecibo