Today’s Wonder of the Day was inspired by tariyah from , AL. tariyah Wonders, “how many people are in the world all together” Thanks for WONDERing with us, tariyah !

Do you like to count? Try counting the number of people in your family. That's easy, right? How about the number of students in your classroom? That's still not much of a challenge. But what about the number of people in your hometown? Or your state? Or your country? Or on Earth?

Have you ever WONDERed how many people call this planet their home? Would you believe scientists estimate that the worldwide population of Earth is over seven billion people? That's right! Seven billion people. That's billion…with a “b!"

So exactly how many people is seven billion? It's hard to imagine, isn't it? In fact, you couldn't even count that high if you tried. If you started counting right now, it would take you about 200 years to count all the way to seven billion. You'd be dead long before you got even halfway there!

Where do all those seven billion people live? The ten most populous countries in the world are China, India, the United States, Indonesia, Brazil, Pakistan, Nigeria, Bangladesh, Russia, and Japan. In fact, China and India together account for about two and a half billion people!

Today, the world population continues to increase. That is because more babies are born each year than there are people who die. Experts expect this trend to continue for the next couple of decades. Things were not always this way, though.

Experts believe the world population first reached the one billion mark around 1804. It did not reach the two billion mark until about 1927 — a period of over 120 years. With advancements in science, technology, and medicine, people today live a lot longer than they used to.

This has led to a population explosion in recent decades. For example, the world population reached six billion in 1999 and surpassed the seven billion mark in 2011 — a period of only 12 years, which is one-tenth the amount of time it took to go from one to two billion people over a century ago!

Will the population continue to grow at the same rate? Scientists hope that the population growth rate will decrease as time goes on. As of now, scientists estimate the population at the turn of the next century could be as many as 11 billion!

Is Earth running out of room? Is there enough space for all those extra people? Actually, there is. Earth is a huge place. Even though it's 70% covered by oceans, there's still more than enough room for everyone. How much room is there? A lot!

Scientists estimate that if all seven billion people on Earth stood shoulder-to-shoulder, they would fill an area about the size of Los Angeles. If you wanted those same seven billion people to stretch out so that everyone had room to dance freely, they'd still only fill an area about the size of Rhode Island.

If Earth has the space, what's the big deal if we add a few more billion people? The problem is that Earth might not have enough natural resources to sustain that many people. Space is one thing, but food, water, and energy? Those are a different matter altogether.

Each new person added to Earth needs food, water, shelter, and energy. Each person also adds a significant amount of waste that must be disposed of. The seven billion people present on Earth today strain these resources enough as it is. Worldwide poverty is at an all-time high and, despite the fact that there is more than enough food produced around the world, at least one in seven people go hungry every day.

As Earth's population continues to expand, strains on resources will continue to grow. The problem for future generations — your generation and your children's generation — will be to expand, conserve, and better distribute Earth's resource to meet the needs of its growing population.

Wonder What's Next?

Tomorrow’s Wonder of the Day is sweet, delicious, and just a little bit chewy!