How much do you know about Earth? If the answer is "not much," don't worry. Thanks to the hard work by scientists and curious hobbyists, humans today know a whole lot about their home planet - what's in it, on it and around it. So read on to educate yourself, and maybe pick up some conversation starters for parties.

Fact 1: The earth weighs approximately 13,227,735,730,800,000,000,000,000 pounds, AKA 6,000,000,000,000,000,000,000,000 kilograms. How do we know this? Scientists can't put this planet on a scale, after all. It all has to do with Isaac Newton's Law of Universal Gravitation, which can be used to measure the mass of any planet or sun provided we know enough information about it.

Fact 2: The thing that allows all earthly life to flourish is only 10 miles high. This strip of atmosphere, known as the troposphere, is the thinnest part of the atmosphere. It is comprised of 78% nitrogen, 21% oxygen, and a whole lot of other stuff.

Fact 3: Meteorites enter Earth's atmosphere every single day. How many? 100 tons worth! So why don't we notice? Since the meteorites are very small, they burn up before they are able to cause any real damage.

Fact 4: The earth is not round. It bulges in the middle, and this is actually a geoid, or an 'oblate spheroid.' This happens because of how the earth rotates. Another oblate spheroid you may recognize - M&M candies.

Fact 5: Earth is the only planet whose English name is not derived from Latin or Greek. It comes from the Anglo-Saxon word Erda. In Welsh, Earth is called 'Y Byd', and in Swahili it is called 'Dunia' or 'Udongo.'

Fact 6: About 20% of the world's volcanoes are active at any given time. There have been approximately 1500 volcanoes active on earth in the last 10,000 years. It is difficult to know how many volcanoes are on the earth today, however. For instance, scientists have only recently discovered that Yellowstone National Park is actually a giant volcano - and the site had been well known and studied long before then.

Fact 7: The Earth's core is a solid ball of molten iron-nickel alloy, holding steady at a temperature of approximately 5430 degrees Celsius. (The same temperature as the surface of the sun.) This temperature is high enough that even without the light of the sun, human beings could survive on the Earth for a while - though don't take comfort in that, because if the sun's light goes out that will mean Earth's closest star has exploded and therefore the Earth will be destroyed momentarily.

Fact 8: If an American was able to tunnel through to the other side of the earth (and survive the trip through hot molten metal), they would actually end up somewhere between the Indian and the Southern Ocean. So if you plan to take the trip, consider bringing a snorkel.

Fact 9:
The oldest rock formation on earth is located in Tandil, Buenos Aires. These rocks are approximately 2 billion years old and cover 215 miles. The oldest known rocks on earth are located in Hudson Bay in Canada. These rocks are 4.5 billion years old.

Fact 10: Early earth may have been blue and purple. Chlorophyll, the biomolecule that gives plants their green color, absorbs red and blue light while reflecting back green light. Green light is actually the most energetic and effective light for producing energy, so this is more than a big odd that plants would reject it. The current theory is that retinal, another biomolecule currently found in halobacteria, was present in the organisms that existed before plants came into being. Retinal absorbed green light and reflected back blue and red - thus giving off a green color. Because there would have been a smaller amount of green light available, plants may have adapted to the situation by using chlorophyll to soak up the byproducts of retinal organism's dinner.