Slightly misleading headline from BBC there... it should really be "Galaxy may have 'billions of Earths'". There's no proof of it, it's just an estimate/guess. It may well be true, but there's no proof yet.
Billions of earth-like planets. Makes you want to live forever to get to explore all that stuff, doesn't it?
There could be one hundred billion Earth-like planets in our galaxy, ...
The title says:
Galaxy has 'billions of Earths'
In the title we don't have any of the words "could", "might", "may", "possibly", or any other words indicating the uncertainty. To me, that means the title is inaccurate.
I think a more interesting way of phrasing it would be "the rare earth hypothesis, as a candidate solution to the Fermi paradox, appears to be false". Which ought to worry anyone who wonders what else is keeping intelligent life down.
I like his estimate that each sun like star has on "AVERAGE" one Earth like planet. Nothing like stating the obvious. (Everyone knows that we have one planet like earth for our sun like star :))
Rather poorly though. It takes several numbers for which we have no idea of a reasonable guess, multiplies them to get a number. The best we can say about this number (pretty much) is that it is in the interval (0,1]. Which is what you get by the definition of a probability. We then multiply this by several other (somewhat) arbitrary constants to get a number.
Not to derail the conversation, but, question: What impact would the undeniable discovery of alien life have on organized religion? Would theists abandon their beliefs en masse or would they find a way of explaining the new discoveries with their existing doctrine?
While it is not a "core doctrine", my religion (LDS.org) teaches that God has populated other planets- a discovery of life on other planets would only affirm our faith.
Creationism -- the belief that some deity created all we see -- wouldn't have a problem with life on other planets. We see them. What kind of creation would only involve certain planets or creatures?
ID -- the belief that our perceptions can either be of completely natural artifacts or artifacts created as a result of an external intelligent agent -- also not implicated. Interestingly enough, there may be a counter-movement here: if intelligent life were discovered, arguments could then begin to be made that some sort of intelligent agent had some play in our cultural/geological history. That would be new.
This religion-vs-alien life question has been going around since the 1950s, at least. What a lot of people forget is that most major organized religions have been adapting to situations like this since their beginnings. Christianity, for instance, thought of the "world" as basically Eurasia for hundreds of years. People in Africa and the Americas were not considered fully "human" until fairly recently. That meant, for all intents and purposes, that places like the New World were 1) far away and almost impossible to reach, and 2) not part of the normal world, and 3) inhabited by creatures that were somewhat intelligent but not completely human.
Religions, especially successful ones, adapt. I would be extremely surprised to see any impact at all. The more you study it, the more of a non-issue it is.
My early childhood religion always taught me that man was special, so I think there would be an impact if we were to find intelligent life elsewhere. In fact, I feel like that idea that man is so special is used as an argument against evolution. They use the 'disgust' of hearing that humans could be related to modern day apes, and thus is not so special.
As you said, religion would have to adapt, but that is an impact. I'm more curious what path they would take. As you said, they could deny them full privileges of being sentient...that is they are less than human. Or they could accept them as being on the same level, but that would require a small alteration to their beliefs.
Worst-case for religion, I guess, would be the discovery of obviously super-intelligent beings who claim that belief in God is an evolutionary defect.
Seems to me that Judaism is a major world religion that applies for Jewish people, although there are many kinds of people in the world.
Christianity is a religion of mankind, hence the need to dehumanize native peoples. The logical progression would be that Christianity would simply follow the lead of Judaism, i.e., Christianity is just for men.
Of course, that's a big-picture, long-range guess. One of the reasons Christianity is so resilient is that there are so many versions. What would happen would be a thousand different possible ways forward. Most wouldn't last 200 years. A few would succeed.
The "man is special" disgust with coming from monkeys thing is just a limited reaction to Darwinism. It's already dying off. Within another 300-500 years it'll be completely gone. There were similar reactions against Copernicus.
He claims to start with one assumption, but actually starts with many. For instance he implies "any species which could colonize the galaxy, will". I don't accept that all possible intelligence would try to take over the galaxy.
He also says that it's not in an alien's interest to leave one planet (Earth) just in case we develop - but he doesn't consider that they might have colonized the galaxy but left Earth precisely because they did find life on it. Even the slightly unimaginative at times Star Trek had the idea of humans only colonizing 'empty' areas and leaving anything with existing life on it alone.
Also, he states that colonizing the galaxy takes ~110,000 years because humans took 10,000 years to evolve + 100,000 years to cross the galaxy. He completely ignores that humans actually took many tens of millions of years to evolve from scratch not from existing life forms.
Also, he assumes zero chance of catastrophic accident leading to exctinction as an explanation for why aliens might not exist. Maybe they did exist but wiped themselves out.
Also, he assumes 100,000 years to cross the galaxy, but that means traveling pretty much at the speed of light, which is currently not possible/forseeably practical. Yet he doesn't consider how aliens would stay as a coherent civilization when a light speed ping response starts taking years, let alone tens of thousands of years.
Also, he doesn't consider any kinds of future technology, IT, AI, singularity or similar. Maybe any culture which gets a thousand years past where we are now does not become a galactic conquerer, but a Matrix-style virtual reality.
Lastly, what if aliens decided the best way to colonize the galaxy was to spray terraforming machines and life seeds, and we are the 'alien' intelligence colonies? Who says alien ideas of 'colonize' have to be like human Earth colonies of the last thousand years?
He completely ignores that humans actually took many tens of millions of years to evolve from scratch not from existing life forms.
Kulisz responded:
The point is that it didn't have to. Nothing in the universe prevented a technological civilization from arising 8 billion years ago. And certainly not 65 million years ago back when the dinosaurs ruled.
Do they believe that only Earth-like planets can support life? Or is it that Earth-like planets are one type of planet that supports life, with many other possibilities? I would think the first assertion to be short-sighted.
I agree with you. We know that our planet and the qualities that it possesses are appropriate for sustaining life. Who's to say a form of life couldn't arise on a planet incapable of sustaining life as we know it. Would that life, then, view our planet as incapable of sustaining life? If it did bump into us, would an intelligence arising on a planet "incapable" of supporting life even see us as life forms?
Most likely only those planets exposed to our sun would have had any warming similar to us (or cooling as is happening now), but I would need some help mounting an expedition to find out for sure. :)
Earth is complex product. Tides, created by the Moon, are important to mix water and to clean coasts. Metal core of the Earth is producing magnetic shield. All that is created due to collision of Earth with large object, which is comparable to Earth, and capturing it.
It is unlikely, that our Galaxy will contain too many systems created by two objects with comparable mass, because such systems are unstable. We can calculate this number by comparing number of star systems with two comparable stars in the system to number of regular stars.
Billions of earth-like planets. Makes you want to live forever to get to explore all that stuff, doesn't it?