(1) The Earth Is Not Round
The Earth is not round as people think or say. It is a sphere, but due to its gravitational forces it is not a perfect circle. In fact, there is a bulge around the equator because of this. The Earth's Polar radius is 3,949.99 miles, while its Equatorial radius is 3,963.34 miles. That's right: the Earth has love handles.

(2) The Name “Earth” Comes From Anglo-Saxons
Every other planet in our solar system is named after a Greek or Roman God, except our planet. Our planet's name, the word Earth comes from the Anglo-Saxon word Erda, which means “ground” or “soil” and is thought to be 1,000 years old. Ironically, the planet is covered by 71% water - the only planet we know of in the entire universe to have this precious fluid in liquid form.

(3) There Are Not 24 Hours In a Day
Some busy people often claim that there aren't enough hours in the day and they're right – not even 24 as they quote. That's right, the actual time it takes the planet to rotate on its axis is 23 hours 56 minutes and 4 seconds. This is what's called a sidereal day. The solar day, the time it takes for the Sun to return to the same spot on the meridian, varies as much as 16 minutes throughout the year, due to the position in its orbit.

(4) Earth Is the Only Planet With Plate Tectonics
Scientists believe the Earth is made up of 7 major plates of “crust,” which move in different directions up to 4 inches per year. When they crash into each other, the theory goes, mountains are born; where they pull apart we have valleys. On the scary side these also cause earthquakes and volcanoes. The good news is that all this activity allows for carbon - essential to our very existence - to be recycled and replenished, allowing life as we know it to continue.

(5) Earth Had a Twin Planet Called Theia
Scientists now believe that we were once not alone in our orbit around the Sun – we had a “twin” planet we call Theia, which was the size of Mars and was 60 degrees either in front or behind our Big Blue Ball. One afternoon, about 4.533 billion years ago, Theia crashed into the Earth; most of the planet was absorbed, but a large chunk blew off and combined with materials from our planet to create the Moon.
Why do we think this? It's because our Moon is unusually large for a planet of our size and has metallic isotopes similar to those on Earth.

(6) The Mysterious Moon's (Almost) Perfect Orbit
Speaking of the Moon (and that is its official name) one thing is for sure: It is NOT made of cheese. Aside from that, there are some things we don't know. For example, the lunar centre is 6,000 feet closer to the Earth, which should cause its orbit to be more wobbly or erratic, yet it is almost perfectly circular. The Moon is covered in a dust that strangely smells like gunpowder, even though they are completely different materials. Also, while there is no “dark side” of the Moon, the Earth's gravitational force has caused the Moon to slow down so it rotates just once during a 24-hour period (referred to as "synchronous rotation") - that's why only one side faces us. In addition, it's quite an incredible coincidence that the Sun happens to be both 400 times bigger than the Moon and also 400 times farther away from the Earth, making them appear the same size in the sky.

(7) The Oceans are Over 90% Unexplored
So, we've (allegedly) been to the Moon and to Mars, but guess what? We have barely begun to visit our own planet, the Earth - the depth of our vast oceans. In fact, only less than 10% of the deep blue seas have been explored. The ocean contains 97% of our water and 99% of the living area. While we have identified 212,906 marine species, there are possibly 25 million more that we DON'T know about. Suddenly, the Loch Ness Monster doesn't seem so far-fetched.

(8) Coldest Temperature: -128.6 F
While the coldest place on Earth is Antarctica (-100 degrees F) the coldest spot was recorded on July 21, 1983 at Vostok Station in Russia, where sensors recorded –128.6 degrees F. Which one the hottest spot recorded? On Sept. 13, 1922, El Azizia, Libya registered 136 degrees F.

(9) Highest Point on Earth is Not Mount Everest
True, it's one of the most famous mountains in the world, and at 29,035 feet above the sea level it's pretty darn tall. However, considering we now know that the Earth is not round (see #1), anyone or anything along the equator is slightly closer to the stars. This means that although Mount Chimborazo in Ecuador is just 20,564 feet above sea level, because it is on this “bump” it is technically further away from the Earth's center (i.e. “higher”) than the Everest, by 1.5 miles!
Read more at http://www.oddee.com/item_98433.aspx#44v1Sf2wKPdf6Edk.99

(10) Why the Month of February Has 28 Days?
The shortest month of the year seems to have gone by in a flash. Why does February have only 28 days?
It's the Romans' fault. Our modern calendar is loosely based on their old, confusing calendar. Though records on the Roman calendar are sparse and sketchy, legend has it that Romulus the first king of Rome, devised a 10-month lunar calendar that began at the spring equinox in March and ended with December. It is unclear whether there were any official months between December and March, but it's likely they were left off because the winter-time wasn't important for the harvest.

The second king of Rome, Numa Pompilius decided to make the calendar more accurate by syncing it up with the actual lunar year which is about 354 days long. Numa tacked on two months - January and February - after December to account for the new days. The new months each had 28 days. But that didn't sit well with Numa because even numbers were considered bad luck at the time. So, he added a day on to January, giving the year an odd-numbered 355 days. No one knows why February was left with 28 and remained an unlucky month.

It may be related to the fact that Romans honored the dead and performed rites of purification in February. (The word februare means "to purify" in the dialect of the ancient Sabine tribe.) The 355-day calendar also couldn't stay in sync with the seasons because it didn't account for the amount of time it took for the Earth to orbit the Sun. So, an extra "intercalary" month of 27 days was inserted after February 23 every couple of years or so to even things out. The Pontiffs who were in charge of calendar upkeep didn't always add the extra month on schedule. Some officials took advantage of the system to extend their time in office, for example. Its again a theory and does not reconcile with Julies Ceasar correction.

In around 45 BC, Julius Caesar commissioned an expert to put aside the lunar origins of the Roman calendar and make it Sun-based, like the Egyptian calendar. Caesar added 10 days to the calendar year and an extra day in February every four years. (The leap-year day was inserted after the 23rd, the same time as the old intercalary month). Now, the year averaged out to 365.25 days, very close to the actual average length of a year: 365.2425 days (and even that varies).

Some have speculated that Caesar added a day to February when he reformed the calendar - making it 29 days long. The story goes that when the Senate renamed the month of Sextilis to honor the emperor Augustus that day was subtracted from February and added to August in order to make it equal in number to July - the month named for Caesar. But this theory is now believed to be bunk; it's likely that Julius Ceasar never even added a day to February.