Ever wonder how much of the Earths mass is made up of Humans?

How much of the Earths mass is made up of Humans? It's quite an interesting question, so I'm going to do some rough estimations to figure out what percentage of the Earths mass is made up of Humans. Next I'll take it even further and do some extrapolation to see how much of the Earths mass could be "converted into Humans" and how fast it could happen. As our population increases the material for creating all those Human bodies can only come from one place: Earth. The calculations required to do these estimations are remarkably simple so I hope you can spend a few minutes with me to see what the result is. I don't even know the answer yet.

First we need to work out what the average body mass of a human is. This is probably the most difficult part. The Wikipedia page for body weight[1] informs us that the average weight of a person can vary quite a bit throughout the world. If we get the average weight of the 4 countries listed by Wikipedia, the result is about 80kg. However, one must keep in mind that a large percentage of the world are living in poverty and are often very malnourished and underweight. Other sources claim the average weight of a modern Human is about 70kg[2][3]. I will go with the more conservative number of 70kg for my estimations.

To get the mass of all Humans on Earth we need to know how many humans are presently on Earth. As of September 26, 2011, 14:38 EDT, the total world population is at 6,992,664,111[5]. That is almost 7 billion people. Estimations report that by October 31 of this year we will reach 7 billion people[6]. Lets use that clean number for these estimations. If we multiply 7 billion by 70 we will get the total mass of all Humans on Earth in kilograms. The answer is 4.9x10^11 or in simpler terms: 490 billion kilograms. Keep in mind that there is probably a small range of error with that estimation.

Next we need to know the mass of the Earth. For all intents and purposes Humans and everything on the Earth can be considered a part of the Earth's total mass. Once again the numbers aren't exact, Google says the mass of Earth is 5.9742x10^24 kilograms but other sources have a very slightly different number[7][8]. To account for this deviation I have rounded the number down to the closest value which all parties seem to agree on. Now we can move onto the calculations we've all be waiting for. By using the total mass of all Humans and the mass of the Earth we can easily work out what percentage of the Earth is made up of Humans.

Mass of all Humans: 4.9x10^11 kg
Mass of Earth: 5.97x10^24 kg

The equation for calculating a percentage[9] is simple:

(Given amount / Total amount) x 100

thus

(4.9x10^11 / 5.97x10^24) x 100
= 0.0000000000082

Ok...well it's fascinating but that's nothing amazing, it's an extremely small percentage. But lets take a little look into the future. It took us over 100 years to go from a population of 1 billion to a population of 2 billion (1804-1927), but we've gone from 2 billion to 7 billion in under 100 years[10]. As of 2009 the estimated growth rate of the Human population was a 1.1% increase annually[11]. Sounds like a small rate of growth right? Wrong. If that rate of growth were to remain steady it would only take another 250 years before we had over 100 billion people on the planet. In 500 years there would be over one and half trillion people on Earth. Once we get past 900 years we would quickly reach 150 trillion people.

Obviously we wont get that far because there is only about 150 trillion square meters of dry land on Earth[12]. Also remember that as the population grows so does our demand for not only land, but also energy, food and other natural resources. So lets just do some fun calculations to see how much mass we could theoretically extract from the Earth in order to create trillions of Humans. We'll start by using the estimated population in 250 years if we keep growing at 1.1% each year and then look at 500 years and finally 900 years into the future.

100 billion humans have a total mass of: 7.0x10^12 kg (7 trillion kg)
1.5 trillion humans have a total mass of: 1.05x10^14 kg (105 trillion kg)
150 trillion humans have a total mass of: 1.05x10^16 kg (10.5 Quadrillion kg)

thus

250 years:
(7.0x10^12 / 5.97x10^24) x 100
= 0.000000000117

500 years:
(1.05x10^14 / 5.97x10^24) x 100
= 0.00000000176

910 years:
(1.05x10^16 / 5.97x10^24) x 100
= 0.000000176

You can see that if the population were to keep growing at a rate of even 1.1% each year Humans will start to accumulate quite a large mass. The percentages still aren't as dramatic as I was hoping for, our total mass didn't even reach 1% in any of these estimations. However, it's easy to see that we cannot sustain this rate of growth forever. Like it or not we will have to eventually reach a state where we have a 0% growth rate otherwise we are doomed to fail. Similar estimations have probably been done but I was bored and needed something to do. Hope it was at least slightly interesting.

REFERENCES:

1. secure.wikimedia.org...
2. wiki.answers.com...
3. wiki.answers.com...
4. www.physlink.com...
5. www.worldometers.info...
6. www.reuters.com...
7. www.google.com.au...
8. www.universetoday.com...
9. mathematics.blurtit.com...
10. secure.wikimedia.org...
11. secure.wikimedia.org...
12. hypertextbook.com...
13. www.google.com.au...
14. www.census.gov...

ahh no..........

Youre forgetting death rate...........

Another problem is that you're measuring all 7 billion as adults.
You'd have to take a percentage as babies and young adults to get a closer estimation.

You're attempting to answer a very difficult question and I'll certainly give you props for that!

The human mass is earth mass that was repurposed to create us. We grow eating food from the earth and from animals who do and also from the water we drink. When we die our physical mass returns to the planetary mass. We are a part of the planet whether we like to admit it or not.

Originally posted by ManBehindTheMask
ahh no..........

Youre forgetting death rate...........

No I'm not. Check again. I'm using the growth rate. The population increases by 1.1% annually. You can actually use a simple compound interest calculator to work it out. I'm 99% sure I'm correct because I just watched a brilliant lecture that dealt with some similar concepts and he presented similar results that would suggest my calculations are correct. It was this lecture which prompted me to make this thread:



EDIT: There are 8 parts in total, I only posted the first one.

reply to post by Afterthought

Another problem is that you're measuring all 7 billion as adults.
You'd have to take a percentage as babies and young adults to get a closer estimation.

True. That is actually something I didn't consider properly. I'm sure it wouldn't have made all that much difference anyway. The percentages weren't really notable in any way.

reply to post by ChaoticOrder


Were does the mass of a human come from? From magic? No it comes from the earth itself and is given back when the human dies.



So the answer would be zero. As humans add no extra weight.

reply to post by Subjective Truth

So the answer would be zero. As humans add no extra weight.

I didn't claim Humans add extra weight. You haven't understood my thread properly. I am saying our "mass" comes from the Earth, and yes it will go back when we die. But as the population grows the amount of mass contained in the Earth with be "converted" into mass which is used to construct Humans. By the way, be careful not to confuse weight and mass. When I used the term "body weight" it actually refers to the mass of a person. I don't know why, it simply confuses people when they try to learn physics.

If every person on earth was standing on one square meter, or ten square feet, they could all fit easily in Jacksonville Florida. If every person on earth was given four acres of land, they could fit in the state of Texas. There is no reason why everyone can't live like a king, except the corrupt system that hogs and wastes resources.

reply to post by CaptChaos


...and the fact that humans are lazy. We like to be able to get water, food, clothing, luxuries close to us. Isn't this how civilization developed?

reply to post by ChaoticOrder

That is a very freaking good question just for the sake of intellectual honesty. However beware cause you're tackling a very touchy issue such as population control, as you can already see from the knee-jerk reactions.

Originally posted by metaldemon2000
The human mass is earth mass that was repurposed to create us. We grow eating food from the earth and from animals who do and also from the water we drink. When we die our physical mass returns to the planetary mass. We are a part of the planet whether we like to admit it or not.

Greetings tin man
U are a smart ONE... So maybe the Maya was right when they based time on the rotation of our bio-ship?... Or, we may be a Sirius---(B) and just don't know it yet... Due to the fact that our own magnetic ball in the middle of it all... changes gravity on a constant nano-second or faster so much... that in the NOW
veritable's (time&weight) are the sameso masses are asses(just kidding)... and it was not the cycle of life that stays the same 2 create weight or lightness... but more so the magnetic shields up/down around the bio-ship allowing more mass particles in... but don't check out... K'ind of thing

Mr X-ULTRA/POSITIVITY... makes the world go up to a lighter density & and a more better destiny.K'

I applaud this completely pointless foray into academic nonsense. I would offer a criticism, however. It is pretty widely known that we are already exceeding the Earth's sustainable amount of humans, at least given current technology in the areas of water purification, farming, and (debatably) greenhouse gas emissions. To calculate the maximum number of humans, you'd have to look at the total volume of fresh water available (using advanced tech) and divide that by the amount of water needed by each human per day, as well as the amount of water needed for farming to sustain that human in terms of food resources. (Not to mention, I would hope, allowing some fresh water for the creatures and plants of the world, rather than having a nightmarish worldwide urban environment...) I would guesstimate it would not exceed 20 billion even with perfect technology.

Originally posted by Exv8densez
reply to post by ChaoticOrder

 

That is a very freaking good question just for the sake of intellectual honesty. However beware cause you're tackling a very touchy issue such as population control, as you can already see from the knee-jerk reactions.

I know it's a very touchy issue but it needs to be discussed. We can't just go on with infinite growth, unless we find a way to live on other planets very soon. It's not likely to happen. But I was mainly just interested in seeing how much of the Earth was made up of Humans. I knew the talk of population control would naturally follow.

reply to post by Observer99


We could easily have many more Humans if we could live in balance with nature instead of the wasteful and gluttonous lifestyles found in a modern day society. Most of the dry land on Earth is completely unoccupied by Humans. Not that I'm saying we should occupy it all, but it could be possible to occupy a large percentage of it if we developed the right lifestyles.

Every time I read a thread about population it floors me. This has been taught in college level courses for decades.

They know that: all first world nations, have very low birth rates, some are negative numbers. Standard of living and EQUALITY makes the difference, good medical programs.

So? I think if people really value justice, and equality and life, and realize that living on a war and starvation planet is almost like living in Hell, they might decide to work on forcing their leaders to equalize, disclose and overcome by education, and very assertive, but non aggressive ways, ie, no wars, the inequality in this world.

I am just curious how you get those numbers. But nevertheless, this could be an enlightening information for people and nation with rapid human growth rate.