Astronomer (Probably) Has 99% Chance of Being Wrong
Posted by Karl Withakay on September 30, 2010
Astronomers have spotted a so-called Goldilocks planet ( Gliese 581g)orbiting another star. A goldilocks planet is a one that is of the right size to be terrestrial and which lies in the habitable zone of its parent star; conditions which are needed to support life remotely close to as we know it.
During a press briefing, astronomer Steven Vogt, professor of astronomy and astrophysics at the University of California, Santa Cruz said the following:
“Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say, my own personal feeling is that the chances of life on this planet are 100 percent,”
“I have almost no doubt about it.”
This is an astounding statement for any reasonable scientist to make, even one that is an astronomer and not a biologist. I would even say such a statement borders on irresponsible, assuming there isn’t some missing context or qualification to that statement. Professor Vogt is essentially saying that the fℓ term (the fraction of the habitable worlds that actually go on to develop life at some point) from the Drake Equation is 100%, which is extraordinarily unlikely to be true.
Whether or not already developed life flourishes everywhere we look on earth is independent from the likelihood of it developing in the first place. By analogy (admittedly one of the weakest forms of argument), diesel fuel is very hard to light on fire, but burns very well once started.
We really don’t have any reasonable estimate for the fℓ term of the Drake Equation, but I think we can say is significantly less than 100%. If it were 100%, you would expect life to be spontaneously developing all the time. You would expect to be able to observe spontaneous abiogenesis at least under laboratory conditions, and yet, we have not yet ever observed life arising from non-life, therefore it must be somewhat less than common.
Additionally, this planet may be the most habitable world we’ve found so far, but the Garden of Eden it ain’t. First of all, it orbits a red dwarf star, which isn’t ideal. Red dwarf stars are fairly deficient in UV radiation which is probably important to, and may be vital for, the development and evolution of life. Also, the planet is tidally locked with its parent star, meaning one side of the planet is always facing the star and one side is always in darkness- not ideal for moderate temperatures on most of the planet. It’s likely the planet itself would have a Goldilocks zone of its own; the day side is probably too hot, the night side is probably too cold, and the zone bordering the day and night zones is probably the habitable zone of the planet.
Even if my last paragraph regarding the actual habitability of the world in question is totally wrong, even if this planet existed in exactly the same conditions as the Earth in regards to parent star, orbit, composition, magnetic field, etc, there’s just no reason to assume a 100% chance of life. By definition, that would mean life had to instantaneously spring up the moment habitable conditions were achieved, and that life would continue to spontaneously arise all the time. I personally believe (without much supporting evidence) that the odds of life developing in any ideal environment are probably very low, but I will confidently say the odds are significantly less than 100%, and they are less for Gliese 581 g than they were and are for Earth.