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World Population Clock: 7 Billion People. World Population: Past, Present, and Future (move and expand the bar at the bottom of the chart to navigate through time) The chart above illustrates how world population has changed throughout history. View the full tabulated data. At the dawn of agriculture, about 8000 B.C., the population of the world was approximately 5 million.

Over the 8,000-year period up to 1 A.D. it grew to 200 million (some estimate 300 million or even 600, suggesting how imprecise population estimates of early historical periods can be), with a growth rate of under 0.05% per year. A tremendous change occurred with the industrial revolution: whereas it had taken all of human history until around 1800 for world population to reach one billion, the second billion was achieved in only 130 years (1930), the third billion in 30 years (1960), the fourth billion in 15 years (1974), and the fifth billion in only 13 years (1987). Wonder how big was the world's population when you were born?

Growth Rate 10 Billion (2055) GCSE Bitesize - Homepage. Educational Software - Maps, Learn to Read and More. WorksheetWorks.com. Your Age on Other Worlds. Want to melt those years away? Travel to an outer planet! <div class="js-required"><hr> This Page requires a Javascript capable browser <hr></div> Fill in your birthdate below in the space indicated. (Note you must enter the year as a 4-digit number!) Click on the "Calculate" button. Notice that your age on other worlds will automatically fill in. The Days (And Years) Of Our Lives Looking at the numbers above, you'll immediately notice that you are different ages on the different planets. The earth is in motion. The top-like rotation of the earth on its axis is how we define the day. The revolution of the earth around the sun is how we define the year.

We all learn in grade school that the planets move at differing rates around the sun. Why the huge differences in periods? Johannes Kepler Tycho Brahe Kepler briefly worked with the great Danish observational astronomer, Tycho Brahe. Here you see a planet in a very elliptical orbit. The Gravity Of The Situation Isaac Newton.