The Cool Science Stuff Thread

[Peregrinator]

I'm amazed about how little the average person knows about the "size" of things....I've asked smart people to guess the approximate size of the container that could hold all of the humans in the world, in cubic miles. The guess is always hundreds or thousands of cubic miles....The answer is a little more than a tenth of a cubic mile.

That's cool. I crunched some numbers just to see what happened:

Human flesh density = 61-67 lbs/ft^3

170 lb human = 2.65625 ft^3 (using 64 lbs/ft^3)

2.65625 * 6 900 000 000 = 1.8328125 * 10 ^10




5280 ^3 = 1.4719795 * 10^11

1.4719795 * 10^11 / 1.8328125 *10^10 = 8.0312607

It's late and I'm tired, so anyone who feels like checking my math, please do.

 

[Byron In Exile]

That's cool. I crunched some numbers just to see what happened:

Human flesh density = 61-67 lbs/ft^3

170 lb human = 2.65625 ft^3 (using 64 lbs/ft^3)

2.65625 * 6 900 000 000 = 1.8328125 * 10 ^10


5280 ^3 = 1.4719795 * 10^11

1.4719795 * 10^11 / 1.8328125 *10^10 = 8.0312607

It's late and I'm tired, so anyone who feels like checking my math, please do.

The logic looks right except that you have the quotient inverted at the end. You've calculated how many earth-sized human populations would fit into one cubic mile; but if the desired answer is "the approximate size of the container that could hold all of the humans in the world, in cubic miles," then it should be:

1.8328125 *10^10 / 1.4719795 * 10^11, or 0.12451345 cubic miles.

 

[Peregrinator]

The logic looks right except that you have the quotient inverted at the end. You've calculated how many earth-sized human populations would fit into one cubic mile; but if the desired answer is "the approximate size of the container that could hold all of the humans in the world, in cubic miles," then it should be:

1.8328125 *10^10 / 1.4719795 * 10^11, or 0.12451345 cubic miles.

I didn't even notice that. I just flipped it in my head without ever thinking to edit it. I told you I was tired.

 

[chillywilly2]

I didn't even notice that. I just flipped it in my head without ever thinking to edit it. I told you I was tired.

Thats a pretty serious "didn't notice"....I'm glad you aren't working for TEPCO...or maybe you are

 

[stephen55]

You non-metric types make things so much more difficult than need be.

Population of earth.....6.91 billion

Average density of humans...very close to that of water....1 kilo per litre.

average size of a human.....70 kilos

******************************

So....total volume of humanity is about 483.7 billion litres.

That's 0.4837 cubic kilometres.

Round it off to one half of a cubic kilometre.


Isn't metric great?

 

[Weird Harold]

I didn't even notice that. I just flipped it in my head without ever thinking to edit it. I told you I was tired.

My only problem with your logic is that it pretty much assumes a dead mass -- Humanity might displace 0.12 Mi^3, but there'd be nothing human left if you actually squeezed them into that volume.

 

[rosco rathbone]

My only problem with your logic is that it pretty much assumes a dead mass -- Humanity might displace 0.12 Mi^3, but there'd be nothing human left if you actually squeezed them into that volume.

You're opening a can of worms though when you go that route. If you are going to calculate minimal living space, then it seems like you should also calculate minimum space needed for life support.

 

[Peregrinator]

Thats a pretty serious "didn't notice"....I'm glad you aren't working for TEPCO...or maybe you are

No, I mean I looked at it and thought, "Goes in 8 times...that's around .12. Yeah, that's about right."

You non-metric types make things so much more difficult than need be.

Population of earth.....6.91 billion

Average density of humans...very close to that of water....1 kilo per litre.

average size of a human.....70 kilos

******************************

So....total volume of humanity is about 483.7 billion litres.

That's 0.4837 cubic kilometres.

Round it off to one half of a cubic kilometre.


Isn't metric great?

I started doing it in metric, but then I realized I was going to have to convert km^3 to miles^3 in order to compare my answer to the post I was playing with. I was unwilling...

My only problem with your logic is that it pretty much assumes a dead mass -- Humanity might displace 0.12 Mi^3, but there'd be nothing human left if you actually squeezed them into that volume.

I thought about that also...I started by toying with a cylinder, but Lady P was asleep and measuring myself was awkward and noisy.

 

[Byron In Exile]

No, I mean I looked at it and thought, "Goes in 8 times...that's around .12. Yeah, that's about right."

That's what they said at Chernobyl, only they said it in Russian.

I started doing it in metric, but then I realized I was going to have to convert km^3 to miles^3 in order to compare my answer to the post I was playing with. I was unwilling...

km³ * 0.23991276 = miles³

I thought about that also...I started by toying with a cylinder, but Lady P was asleep and measuring myself was awkward and noisy.

A cylinder would waste space. You should have asked Clovis.

 

[Peregrinator]

That's what they said at Chernobyl, only they said it in Russian.

km³ * 0.23991276 = miles³

A cylinder would waste space. You should have asked Clovis.

Yeah, well I wasn't designing a disaster.

I, too, can google conversions.

I didn't like the image of stacked coffins. I figured I'd fill the space with cotton candy.

 

[stephen55]

km³ * 0.23991276 = miles³

Other way around, I think...

1 cubic kilometer equals 0.23991276 cubic miles.

So...by my estimate, the total volume of humanity is 0.116 cubic miles.

Of course, that doesn't include breathing room.....

 

[Byron In Exile]

Yeah, well I wasn't designing a disaster.

You were, it just wasn't implemented.

I, too, can google conversions.

Yet, you were... "unwilling"?

I didn't like the image of stacked coffins. I figured I'd fill the space with cotton candy.

And where did you think you were going to get that much cotton candy?

 

[Byron In Exile]

Other way around, I think...

1 cubic kilometer equals 0.23991276 cubic miles.

Wait a sec...

 

[Peregrinator]

You were, it just wasn't implemented.

Yet, you were... "unwilling"?

And where did you think you were going to get that much cotton candy?

Nah. I wasn't designing anything.

Yep. I was playing, and that route wasn't any fun. It would have been like looking up a word while doing a crossword puzzle.

From English Lady. She's super sweet.

 

[Peregrinator]

Wait a sec...

I would think a mi^3 would be a tad larger than a km^3.

 

[Byron In Exile]

I would think a mi^3 would be a tad larger than a km^3.

km³ * 0.23991276 = miles³

Other way around, I think...

1 cubic kilometer equals 0.23991276 cubic miles.

So...by my estimate, the total volume of humanity is 0.116 cubic miles.

No, it's not the other way around...

"km³ * 0.23991276 = miles³"

and

"1 cubic kilometer equals 0.23991276 cubic miles"

are both correct.

0.4837 km³ * 0.23991276 = 0.116046 miles³

 

[Weird Harold]

Yeah, well I wasn't designing a disaster.

I, too, can google conversions.

I didn't like the image of stacked coffins. I figured I'd fill the space with cotton candy.

How about a "field of phone booths" -- about 3.5 ft^2 by about 7 ft tall == round up to 25 Ft^3 per human.

 

[Byron In Exile]

^ On the other hand, maybe I should have used => instead of = ...

 

[rosco rathbone]

Or just have them all floating in zero gee.

 

[Peregrinator]

No, it's not the other way around...

"km³ * 0.23991276 = miles³"

and

"1 cubic kilometer equals 0.23991276 cubic miles"

are both correct.

0.4837 km³ * 0.23991276 = 0.116046 miles³

See, this is why I don't like unit conversions when I'm not using machines to do them for me.

Now that I look again, yeah, it makes sense that a km^3 is around a quarter of a mile^3.

How about a "field of phone booths" -- about 3.5 ft^2 by about 7 ft tall == round up to 25 Ft^3 per human.

That sounds like a warehouse on the set of Dr. Who.

 

[stephen55]

Q: How much petroleum does the world consume in a year?

A: A little more than one cubic mile.
1.20..............................Cubic Miles

So, at today's rates, all of humanity (0.116 cubic miles of humanity) consumes 1.2 cubic miles of petroleum per year. So each of us today, on average, goes through about ten times our volume in petroleum each year.

Let's see...

The world's population keeps going up.

The world's consumption of petroleum keeps going up.

http://www.japanfocus.org/data/World%20Population%20Growth%20to%202050.JPG

http://www.data360.org/temp/dsg326_495_300.jpg

So...how much longer is our supply of petroleum going to last?

 

[stephen55]

^ On the other hand, maybe I should have used => instead of = ...

....maybe....maybe...

Was it it you who wrote the Chernobyl Nuclear Reactor Safety Manual?

X*Y=Z and X=Y*Z are not exactly the same.

 

[Byron In Exile]

....maybe....maybe...

Was it it you who wrote the Chernobyl Nuclear Reactor Safety Manual?

X*Y=Z and X=Y*Z are not exactly the same.

No, they're not.

But 0.4837 * 0.23991276 = 0.116046

 

[Bacigalupo]

Crap on your math! It's time for wolves!

http://www.livescience.com/13535-poop-reveals-wolf-immigrant-isle-royale.html

 

[stephen55]

The Jan. 27/2011 issue of Nature has an article on the most distant object ever imaged. It is a galaxy at about redshift Z~10. That would have it forming only about 500 million years after the Big Bang.