6 billion people is a lot, I mean a whole lot - but it's really hard to grasp those sorts of numbers. I've often wondered how those figures translate to things I can actually visualize; so I set about finding out.

Please note, this is not a scientific study, heck, I didn't even graduate high school :). It's just a few figures I knocked together over an hour and will likely be revised in the time ahead :).

So, first up - we are no longer 6 billion, not even close; we're rapidly approaching 7 billion.

According to the US Census bureau, at 07:32 GMT (EST+5) Aug 18, 2009, the world's population was an estimated 6,778,357,245 people.

OK, so those folks are all shapes, ages and sizes. So, based on an average measurement, of 40cm (about 15.7 inches) across the shoulders, that means standing shoulder to shoulder:

= 2,711,342,898 meters
= 2,711,342.9 kilometers
= 1 684 750.37 miles

At its closest point, the Moon gets within 363104 km (225622 miles) of Earth. So in that scenario and standing shoulder to shoulder in a single line, we would stretch from the moon and back 3 times, with plenty left over!

What about weight of all the humans on the planet?

Again, it's hard to get that sort of figure when you take into account children, the starving, the obese etc; but let's peg an average at 40kg - about 88 pounds.

= 271 134 2902 tonnes
= 298 874 394 short tons

An African elephant can reach around 7.7 short tons; so our combined weight is the equivalent of 38,814,856 (really big) elephants.

The largest animal on the planet is the blue whale that reach up 100 feet long and weigh up to 150 tons. Our combined weight is equivalent to 1,992,495 blue whales.

What about surface area?

Based on a shoulder span of 40 centimeters and a foot length of 23cm, close enough to 1 square meter - if we were placed pretty closely together, that means we'd cover 6,778,357,245 square meters.

= 6,778 square kilometers
= 2 617.13836 square miles

We would totally blanket the US state of Delaware, standing room only, and substantially spilling over the edges of state lines.

Sure, Delaware is the USA's second smallest state, but imagine driving around entire state and it being covered by people. Actually, you couldn't do that without squishing quite a few.

Another way to visualize it is a fairly solid column of people 1 mile wide and over 2,600 miles long.

The mind really starts boggling when you then take into account crops and livestock needed to feed and clothe all these people.

According to some figures I've seen bandied around, it takes around 1.2 acres of arable land to provide one human with a "diverse" diet; which I assume includes some sort of meat/dairy and poultry. Of course, our Western diets require much more.

As we're all well aware, many people do not have sufficient to eat - but lets say that 1.2 acres was available and utilised and there were 6 billion teens/adults on the planet. That would mean 7.2 billion acres are needed.

The entire country of Australia consists of only 1.8 billion acres - and much of that is desert. There's 2.3 billion acres of land in US - still nowhere near enough and again, there's a great deal of unsuitable land for growing food in the USA.

This land usage doesn't even cover other raw materials for making our creature comforts.

We're certainly not an endangered species - quite the opposite; our poor planet is already buckling under the load. The UN projects a population of 8.9 billion by 2050. How will Planet Earth cope?

This is why population control is the ultimate greening.