Population of the Galaxy

[Lance]

This is probably a question for Mactep:

If the Milky Way is 100,000 light-years in diameter and advanced, technological civilizations (TCs) are evenly spaced at 1,500 light-years apart, I put that at just shy of 3,500 TCs. The average thickness is just 1,000 light-years so I was only considering 2 dimensions.

Is that close to right?

[tubeswell]

If the Milky Way is 100,000 light-years in diameter and advanced, technological civilizations (TCs) are evenly spaced at 1,500 light-years apart, I put that at just shy of 3,500 TCs. The average thickness is just 1,000 light-years so I was only considering 2 dimensions.

Is that close to right?

Depends on the backstory

[Мастер]

This is probably a question for Mactep:

If the Milky Way is 100,000 light-years in diameter and advanced, technological civilizations (TCs) are evenly spaced at 1,500 light-years apart, I put that at just shy of 3,500 TCs. The average thickness is just 1,000 light-years so I was only considering 2 dimensions.

Is that close to right?

That is extremely close to what I'm getting if we assume they're on a square grid. If we put them in hexagonal cells, then I'm getting that it should be about 15.5% higher. But that's after a nice 0.5 litre dunkel lager at the wurst restaurant.

[Lance]

Depends on the backstory

[Lance]

That is extremely close to what I'm getting if we assume they're on a square grid. If we put them in hexagonal cells, then I'm getting that it should be about 15.5% higher. But that's after a nice 0.5 litre dunkel lager at the wurst restaurant.

That makes sense to me. I just divided the area of the 100K LY circle by the area of a 1.5K² LY square so that would make it a grid.

How do you figure it for a hexagon?

We should work on this. Maybe we can replace the Drake Equation with the Clarke/Mactep Equation.

[Мастер]

That is extremely close to what I'm getting if we assume they're on a square grid. If we put them in hexagonal cells, then I'm getting that it should be about 15.5% higher. But that's after a nice 0.5 litre dunkel lager at the wurst restaurant.

That makes sense to me. I just divided the area of the 100K LY circle by the area of a 1.5K² LY square so that would make it a grid.

How do you figure it for a hexagon?

We should work on this. Maybe we can replace the Drake Equation with the Clarke/Mactep Equation.

The way I figured it, draw a column, each point 1.5 away from the last. So far, it's exactly the same as with the square grid.

Now, draw a second column, just like the first. Except, instead of having each one be right next to the corresponding point in the first column, have them offset. So vertically, each point in the second column should be halfway between two points in the first column. These three points should form an equilateral triangle. So to get from a point in the first column, you can move down 0.75, and to the right 1.5*sqrt(3)/2. (By the Pythagorean Theorem, you have moved 1.5 along the diagonal.). So instead of the points in the second column being 1.5 to the right of the first column, they are 1.5*sqrt(3)/2 to the right. Packed a little closer. The ratio of the spacing is [1.5*sqrt(3)/2]/1.5 = sqrt(3)/2. So you can fit 2/sqrt(3) times as many points in the same area. This is about 1.155 times as many.

I'm not sure how well that comes across in words; there isn't an easy way to do a diagram, is there?

[Enzo]

The Drake equation: one starting premise, then a series of nested arbitrary factors, each multiplying the last. The result being a range of possible answers covering many orders of magnitude.

How large is your new robot? Oh, somewhere between a bacterium and a blue whale.

How much weight did my wife lose? Oh somewhere between a nanogram and 3000 kilotons.

"Dr.Drake, how many civilizations are there in the universe?" Oh, somewhere between one and....

[Lance]

I'm not sure how well that comes across in words; there isn't an easy way to do a diagram, is there?

That came across just fine. Yup, I get it, and it makes perfect sense. It's just like fitting a bunch of round things in a rectangular container. You'll fit more if you stagger them.

"Dr.Drake, how many civilizations are there in the universe?" Oh, somewhere between one and....

Which is exactly accurate.

[tubeswell]

Depends on the backstory

The assumption that (TCs) are evenly spaced at 1,500 light-years apart?

[Lance]

The assumption that (TCs) are evenly spaced at 1,500 light-years apart?

Ah, yes. It's purely a flight of fancy for sure. Just something to keep me amused.

[Enzo]

Since the numbers are all arbitrary, couldn't we just state whatever statistics we like without the need for any calculations?


I used to do an exercise to make some point or other somewhere else. I imagines a football stadium with 100,000 seats selling for $10 each, and 100 super box seats at $10,000 each. So $1 million in cheap seats, and $1 million in expensive ones. $2 million of seats. 100,100 total seats. So average is $19.98 per seat. Which doesn't resemble the price of either. We could have 10 TCs over in one corner of the MW, and another way over the other way, and they average out to 1500LY, but that doesn't mirror the real distribution.

[Lance]

Yeah, it's a lot of "ifs". But for me, ifs are fun. As humans, if we didn't "if", we'd still be living on the plains of Africa.

[Enzo]

Some of us still do, we say things like "praise the lord".

[Lance]

Good point.

[Мастер]

I've been to the plains of Africa. I even made an illegal border crossing there once, and a short time later, another one (to go back).

I like the plains of Africa.

[MM_Dandy]

I hear it rains down in Africa.

[Мастер]

I hear it rains down in Africa.

I've been caught in the rains. But it rains in SE Asia as well.

Unfortunately, it is not raining now, as that might help with this weeks-long chemical/biological warfare Indonesia has been waging against us.

[Lance]

I hear it rains down in Africa.

The wild dogs cry out in the night

[Enzo]

The plains of Africa. Suddenly I am struck by an image of Serengeti Amish folk.

[Heid the Ba]

I hear it rains down in Africa.

The wild dogs cry out in the night

As they grow restless longing for some solitary company

[Lance]

I hear it rains down in Africa.

The wild dogs cry out in the night

As they grow restless longing for some solitary company

I know that I must do what's right

[MM_Dandy]

I hear it rains down in Africa.

</snip>
I know that I must do what's right

Sure as Kilmanjaro rises above the Serengeti.

...It's "I bless the rains down in Africa, isn't it?
Still, pretty well took it of the rails anyway, so I guess I'll offer some actual grist for the mill.

I consider myself more or less an optimist concerning extra-terrestrial life (and no, I am not deferring to my particular religious beliefs). It's a big darn universe, surely there's another Earth or two out there with the magical Earth-like experiences and conditions that have brought us about. But, as we continue to not find definitive evidence of past or present life on Mars, despite finding that it has or had ever-more favorable conditions for it, I'm starting to temper my assumptions.

[Heid the Ba]

I'm the same, surely there must be some other creature/race/beings out there? And don't trouble me with your science showing there doesn't have to be. I'm quite happy on this small blue dot never meeting or contacting any aliens, I just choose to think we can't be all there is.

Let's try again:
I hear the drums echoing tonight

[Enzo]

I tend to think there is other life, even civilized life, out there, but I also think we will never know of it.

[Lance]

I hear it rains down in Africa.

</snip>
I know that I must do what's right

Sure as Kilmanjaro rises above the Serengeti.

...It's "I bless the rains down in Africa, isn't it?

It is. I wasn't sure if this was your intention or just a comment, so I figured I'd run as far as I could with it.

Let's try again:
I hear the drums echoing tonight

But she hears only whispers of some quiet conversation

---

I tend to be very optimistic about the existence of alien life. I base this on these two facts about the Earth:

1. Every place life can exist, life does exist.
2. As soon as life could exist, life did exist.

Considering that water and organic compounds appear to be ubiquitous and there are exoplanets everywhere we look, I would be shocked if we're all there is.

So I think simple life will eventually be found everywhere, including many places we would have thought to be uninhabitable.

Regarding the lack of evidence of life on Mars, clearly there are no multicellular animals currently living there, and we haven't yet sent anything there to see if there ever had been. The current rovers also don't have any way to directly test for the existence of even simple life. So unless we flip over a rock and find fungus or lichens on it, we're not going to find life that way either.

My personal opinion is that simple organisms do still survive below the surface of Mars but it will take more effort to confirm this. Nothing I've seen so far discourages this. Of course, Mars could very well be dead, or may have never developed life at all.

Evolving intelligence is a completely different matter. If you can get to multicellular organisms and diverse species then I think the jump to complex life and intelligence is pretty simple. But if the best you can do is green slime then... So to me, the biggest question is: how hard is it to go from very simple to more complex life forms?

If life does end up being everywhere then at least some of these will be able to go further. Evolving intelligence, to me, is having things like dolphins, octopi, dogs, etc. Animals that can solve problems by thinking about them. The leap to technology is a big one. There might not be very many, if any, other technological civilizations out there. Or it might be a niche that needs to be filled and will always evolve when possible.

We've had 5 major mass extinctions on the Earth, including the Permian which took out ~96% of all life including insects just 250MYA. What would life be like here if we hadn't lost so much relatively recently, geologically speaking. It only took ~65M years to get from proto-mice to beings that can contemplate all this. What would it be like if we'd had an extra quarter of a billion years? Other planets may have even more, greater mass extinctions but others may have fewer, or none to speak of.

There are so many variables and so many questions. I love it! Contemplating and considering all the possibilities is one of my favorite things.