Vexen Crabtree 2015


Vexen Crabtree's Live Journal

Sociology, Theology, Anti-Religion and Exploration: Forcing Humanity Forwards

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Vexen Crabtree 2015

Life's BIG questions...

Do any of you know:

1. What are some estimates as to the size of the universe?

2. What are some estimates about how many planets & moons are habitable by people?

3. What is the radius of the Earth?

4. To what depth in metres, and to what height, do humans live? I.e., we live from 20m below sea level in some places, to 3km above sea level in others? What's the range?

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1. the universe is larger than 93 billion light years, acording to wikipedia.
and of kcourse, We can be sure that radius in light years is greater than it's age - as we can't see the edges.

2. there's not enough data to even make a guess on how many would be habitable - but I can say that right now there are none, as we have no way of getting to them to do any habiting.

3. 6,371.0 km

4. 20m below and 3 or 4 km above sounds about right. Unless you count people currently resident in orbit, or who are currently in planes etc.

why anyway?

Go girl, that's awesome! I partially wrote the entry to remind myself to look these values up.

Gawp at it, but I want to give what fractions of the Earth, and of the Universe, are potentially habitable by people! To do that I need radius's of the Earth, calculate the % of that which is habitable, multiply by the potential number of planets, get their total volume, and get the % that that is of the universes' total size.

There, now you know why I'm after those values! Begs another question :p

% habitable...

I have a question...

What part of the electromagnetic spectrum is inhabitable?

The amount of the total electro magnetic spectrum allowed to the earths surface (predominantly the visible light spectrum) is less than 1 trillionth of a trillionth or approximately 1/1,000,000,000,000,000,000,000,000th of the total spectrum.

The other wavelengths in the spectrum are lethal or useless to the immediate needs of carbon based life.

There is some good info on the subject here at about 5 minutes into the video:

This link will only take you to part 3 of 6.

There is a wealth of information from astrobiologists using solid emperical science on in this video as to the habitability of the universe. It also touches on the question of life other than carbon based.


Some calculations already done...

Vexen, you may or may not agree with the assesment of the astrobiologists on this documentary, but you will find the information useful in making your own calculations.

In part 3, they tell us what their calculations show in terms of getting the known and commonly accepted factors needed for life in one place and time. They say that probabilities of getting all the factors is 1 in 1,000,000,000,000,000,000 or 1 onethousandth of 1 onetrillionth.

It's not a direct correlation to your question of what percentage of the universe is habitable. Rather it shows why virtually none of it is. That is quite contrary to the domminant cultural assumptions and philosophy in highly publicized circles.

But as Chris mentioned below, our knowledge base is in flux. so the figures could change in the future. I see them only getting worse in terms of probability. Like junk DNA, as we learn more, we find it serves other purposes. So those are at least predictions that might sustain the hypothesis in the future. Any good theory should make predictions you know...

They claim in the documentary to be quite conservative so as to give us a flavor for the difficulties without claiming a definitive calculation. I find it all very reasonable. But perhaps I am blinded by my own philosophical leanings. But it seems to me that this entire excersize is done with almost robotic objective discipline. I mean the evidence is bound to sustain someones philosophy. It doesn't always mean that the research is motivated or degraded by one's bias.

I have studied these arguments very thoroughly and could write quite a bit about them. But if your really interested, you can watch it yourself.

Here's a copy and paste link to part 3:

Yu really have to watch the whole thing to appriciate the context of the arguments. So don't dismiss one strand of the reasoning out of hand without weighing the whole context.

The conclusion of the whole thing... ...that the universe is severely inhospitable to carbon based life in general. That mathematically speaking, there are impossibly small parameters neccessary for life.

1- REALLY big.
2- Not that many considering how many planets and moons there are
4- I dunno you gave the outer limits in different measurements! :O

They are some very, interesting, big questions.

You came up in conversation round our dinning table the other night. Strange but true! :P

there is a bit in bill brisons book about this... i might have it at home... if so, ill check for you what he recons... there is a good equation about working out how many planets in the universe are prob inhabited... it us A LOT.

1) So big it's not worth worrying about. It's fecking hayuge. Seriously, it can't be measured at present so don't even bother on that one ;)
2) There is no accurate way of determining how many are habitable by us as we can't see or analyse that far. And our probes can't get that far. So you have to look at theory and what little we do know. Probability of a world/ moon being habitable is remote, but not impossible, for us. As for other lifeforms that are none carbon based and you open a whole new realm of possibilities. We have sulphur based life on this planet, although it is very rare. Little bugs living in caverns deep below the ground. But they are sulphur based. Look up Black Smokers for more examples of life in unusual places and how it adapts. IIRC there is this lot for the theory, but this will give you a better idea.
3) Wikipedia figures on size of the earth. Remember it's slightly squished due to it's spin so the distance from pole to pole is less than the distance through the equatorial line.
4) It's a pressure thing, assuming it's not a bit wet or cold/ thin on atmosphere. Without life support I do believe the 20m below to 3-4km up figure is accurate.

Edited at 2008-01-31 05:10 pm (UTC)

Actually these life forms are still carbon based. They are not sulpher based.

The only difference is that they use sulfer as a food source, so as to convert it into biological energy.

They are still carbon based. They are still ATP dependant for cellular energy function.


Ah right. Heading into territory that makes me go 'wha?'. I just saw a documentary and that's the wording used. It does however demonstrate the ability for our little niche of 'life' to adapt to some very weird turf, which I believe was part of Meester Vexens interest.


Yup, think I just saved that ;)

Science or philosophy? (Anonymous) Expand
Re: Does that make sense? (Anonymous) Expand
Misread... (Anonymous) Expand

Not sulfer based in that way...

Actually these life forms are still carbon based. They are not sulpher based.

The only difference is that they use sulfer as a food source, so as to convert it into biological energy.

They are still carbon based. They are still ATP dependant for cellular energy function.


I'm sure that you can get informed and sensible answers to these questions, so I'm going to toss out my best guesses to see if they're close to the mark.

(30% confidence) The limits of the observed universe lie at about 9 billion light-years and these areas (as observed from here and now, due to light-propagation delay) are believed to date from very close to the Big Bang. So at least 20-odd billion light-years across. But there are limits to the observable universe, and for all we know there's a lot more beyond that.

(50% confidence) Within the Solar System, inhabitable by people in their native, unprotected state? Exactly one. It is perhaps feasible that Mars could be terraformed; two. Beyond that you have to invoke steadily greater technological infrastructures to protect us from vacuum (the moon), great cold (any outer planets), great heat (the inner planets), dropping into the planet's core (the gas giants), and so on. Outside the Solar System... some gas-giant-sized planets have been observed orbiting other stars, but as yet we are unable to observe rocky planets of Earth's size. Given that the Sun has several, it's tempting to speculate that such planets are common, but of course the likelihood of compatible biospheres is zilch.

(100% confidence) Slightly under 4,000 miles.

(60% confidence) To actually live, to dwell: from the Dead Sea (-300m, I think?) to about 6,000 metres. Much above that, and the human body begins to suffer inexorable degradation from oxygen shortage.

Now I'll go and see what the real answers are. *wag*

The survivable range is pretty much determined by oxygen levels, if your trying to guestimate livable surface in the universe it's going to depend as much on how it's configured as to how much is there. eg alter the oxygen mixture or gravitational pull and the max height changes.

On Everest the death zone is considered above about 7600m but I'd consider livable limit to be closer to the 4000-5000m based on the Peruvian Andes plateaus, where the locals can live and breed OK because of evolutionary adaptations but when the Spanish moved in, they survived but could not carry pregnacy to termination and have a surving offspring. Suggesting it's pretty near the limit for a breeding colony of humans.

I've no doubt that if there were lower places on earth humans could survive somewhat lower than the Dead Sea though as it doean't have an equivalent only the adapted can breed limitation.

Re: Morality and religions part 3...

Ok. Here's the deal. If you are happy with your beliefs and they work for you it's bloody irritating for someone to walk up and say 'you don't want to do it like that, you want to do it like that'. Beliefs are a very personal thing afterall.

Christians badgering pagans for no reason. Ok it's badgering now not murder, so things have improved, but yes. Still irritating. And also very patronising. Speaking personally I had my awakening during a period when I was in a very bad way and in an awful position. This was my sacred wound. I reached out for help and had the Kaballah visualisation. It was 5 years on when I found out the vision I had had was the Kaballah visualisation. Exact description. I just said 'Blimey!'. You know the wierd thing though? It happened in the year 2000, and seeing as the events I was caught in left me so badly injured I'm now classed as disabled and yeah. I was nearly murdered in my own home.

Now I try to be careful. The injury was me being left Paranoid Schizophrenic. I have to be careful on that one. The number 13 and 7 show up in my life rather a lot, and that's kinda wierd as well. So I take everything with a pinch of salt and adopt the 'live and let live' attitude. Seems best to me.

It does indeed come down to morality. Totally. Which ever group you fall into there will be good and bad in every group. Christians have dodgy ones ( some Catholic priests being kiddy-fidlers etc etc ), and so do Pagans ( my attackers were Pagan ), which is why I fall to the white. I try to be one of the good guys. I may not get it right all the time, but at least I try.

So, I have a faith that has helped me recover from those injuries that I discovered during the infliction of those injuries. It involves introspection which is a standard counselling tool, as well as eating well, looking after friends and loved ones, being a good person, and simply doing the best I can. I can't see anything wrong with that at all. And it's worked for me. And the introspection is all recorded and is down to self-analysis. A tool used by trained professional counsellors to great effect. Nothing dodgy there then.

Re: Alien visitation...

Let me ask you this...

If an alien race actually did land, would we be foolish to keep believing what we think 'works for us'?

Or would we accept reality?

Re: Alien visitation...

I would accept reality. It's real and in front of me, and just confirms how very complex and interesting creation really is. Which would make 'the creator' even more impressive. But my faith allows for that. A more stringent faith may not. God created man and there are no aliens etc etc. Then aliens show up and say w3rd. I doubt I'll be the one say 'oh eck, my doctrine'. Some more stringent, or extreme, faiths may well have to sit down and have a think though.

But that's faith. No-one knows if they are right or wrong to the end. Hence stepping out and into the simpler 'good and evil' bit.

Is that a no? (Anonymous) Expand
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