...that I felt was more appropriate here under this Philosophy of Science heading.Greta wrote: ↑December 18th, 2017, 5:21 pmHuman minds struggle to grasp exponentials. A hundred billion galaxies (minimum), each with many billions of solar systems. The total number of solar systems is conservative estimated as a billion trillion. Meditate on that number for a while. There is no way of getting one's head around such odds. lot more is possible in reality than we imagine.
It concerns the "rare earth" hypothesis; the idea that intelligent, technological life might be restricted to planets that have an exceedingly rare confluence of circumstances, with the Earth being as possibly the only one in existence that can generate a technological species.
To be clear, this hypothesis does not mean that there isn't life on other planets. There is a high possibility of life in the oceans under the ice on Europa (would we call them Europeans?), possibly similar on moons of other gas giants, and there are indications that Mars may harbour something akin to bacteria. It's my contention that life is ubiquitous throughout the universe; it's just that the circumstances that give rise to technological life are so rare as to be almost non-existent, except for us.
Now, I know that sounds ego-centric, and to be sure, I really really want to be wrong on this. But this is how I see it anyhow:
Earth enjoys a number of circumstances which have been theorized to be necessary for the rise of life. Some of them include:
- Earth is in the habitable zone, meaning that it is the correct distance from our star that surface water can exist. It doesn't stay frozen, it doesn't boil off.
- We have a single moon which creates regular tides.
- These regular tidal forces create tide pools which may have been vital in the development of single-celled lifeforms.
- Our solar system is populated primary by gas giants, which have a tendency to "hoover up" the detritus that flies through the solar system and impact planets
- Earth has a molten core, and as a result of this, the planet has a magnetic field which shields us from coronal mass ejection material and the solar wind. If we did not have this magnetic field, the atmosphere would likely have been stripped away.
- Our planet is alive with plate tectonics which, it has been demonstrated, has been vital in the development of life.
- Our atmosphere contains ozone in the upper atmosphere. This ozone filters out much of the harmful UV radiation which would make life as we know it impossible.
- It is a well-established fact that chaotic interactions and some blind luck were involved in the rise of intelligence. Were it not for an asteroid strike 65 million years ago, the dinosaurs would probably still be the dominant life-form, and our ancestors would still be scurrying about underfoot. There are countless lucky coincidences that had to take place - most importantly, the taming of fire by proto-humans - that were required to bring about a species capable of developing technology.
- There's also the problem of the "great filter" which you can read more about here: The Reason We’ve Never Found Intelligent Life Might be Because We Are Already Going Extinct
But another number that is astronomically large is the combinant ratio of the above-noted events, and likely hundreds or thousands additional events, that were necessary for the development of technological life.
So, yes, there are billions of planets. How many planets are in the habitable zone
have a single moon
that moon is at the right distance and size to create tidal forces
is in a system that is populated primarily by gas giants
has a molten core with a magnetic field
has plate tectonics
has a blanket of UV-reducing ozone in the upper atmosphere
had an asteroid impact that "cleaned the slate" to allow for the development of something like mammals
has not been through the "great filter"
the list continues on, and on, and on...
Miss out any one of those variables and, based on the information we have - which, I recognize, is a sample size of one - technological life would not have arisen.
Again, and I want to re-iterate here, I really want to be wrong on this. But, paraphrasing Sean Carroll, we must be very hard on those hypotheses that we want to be true.
I want it to be true that intelligent, sentient, technological life is abundant in the universe. But I just can't get my head around the numbers of happenstances that have to take place, in some sort of order, for technological life to arise.
What are your thoughts? Are we in a universe that is teeming with technological life and we just haven't found it (or it hasn't found us), or is it too far away, or are we the one-and-only technological species?