Interesting Facts about Earth you Haven't heard before

Interesting Facts about the Earth

1.Aliens on Earth

Alien worlds may be all the rage, with their mystique and promise, but the orb we call home, planet Earth, has all the makings for a jaw-dropping blockbuster movie: from the drama of explosive volcanoes, past meteor crashes and catastrophic collisions between rocky plates to the seeming fantasy of the ocean's deep abysses swirling with odd life and tales of the coldest, hottest, deepest, highest and all-out extreme spots.

Did you know Earth is not actually a sphere? That we are rocketing around the sun at 67,000 mph? That the majority of Earth's fresh water is locked up in Antarctica?

We pawed through our archives to gather together just 50 of the most amazing and interesting facts about Earth. Enjoy the journey.

2.We're the third rock from the sun

Our home, Earth, is the third planet from the sun and the only world known to support an atmosphere with free oxygen, oceans of liquid water on the surface and — the big one — life. Earth is one of the four terrestrial planet: Like Mercury, Venus and Mars, it is rocky at the surface.

3.We're the third rock from the sun

Our home, Earth, is the third planet from the sun and the only world known to support an atmosphere with free oxygen, oceans of liquid water on the surface and — the big one — life. Earth is one of the four terrestrial planet: Like Mercury, Venus and Mars, it is rocky at the surface.

4.The planet has a waistline

Mother Earth has a generous waistline: At the equator, the circumference of the globe is 24,901 miles (40,075 kilometers). Bonus fact: At the equator, you would weigh less than if standing at one of the poles.a

5.Earth is old

Researchers calculate the age of the Earth by dating both the oldest rocks on the planet and meteorites that have been discovered on Earth (meteorites and Earth formed at the same time, when the solar system was forming). Their findings? Earth is about 4.54 billion years old.

6.The planet is recycled

The ground you're walking on is recycled. Earth's rock cycle transforms igneous rocks to sedimentary rocks to metamorphic rocks and back again.

The cycle isn’t a perfect circle, but the basics work like this: Magma from deep in the Earth emerges and hardens into rock (that's the igneous part). Tectonic processes uplift that rock to the surface, where erosion shaves bits off. These tiny fragments get deposited and buried, and the pressure from above compacts them into sedimentary rocks such as sandstone. If sedimentary rocks get buried even deeper, they "cook" into metamorphic rocks under lots of pressure and heat.

7.Our moon quakes

Earth's moon looks rather dead and inactive. But in fact, moonquakes, or "earthquakes" on the moon, keep things just a bit shook up. Quakes on the moon are less common and less intense than those that shake Earth.

According to USGS scientists, moonquakes seem to be related to tidal stresses associated with the varying distance between the Earth and moon. Moonquakes also tend to occur at great depths, about midway between the lunar surface and its center.

8.The magnetic pole creeps

Earth has a magnetic field because of the ocean of hot, liquid metal that sloshes around its solid iron core, or that's what geophysicists are pretty certain is the cause. This flow of liquid creates electric currents, which, in turn, generate the magnetic field. Since the early 19th century, Earth's magnetic north pole has been creeping northward by more than 600 miles (1,100 kilometers), according to NASA scientists.

The rate of movement has increased, with the pole migrating northward at about 40 miles (64 km) per year currently, compared with the 10 miles (16 km) per year estimated in the 20th century.

9.The pole flip-flops

In fact over the past 20 million years, our planet has settled into a pattern of a pole reversal about every 200,000 to 300,000 years; as of 2012, however, it has been more than twice that long since the last reversal.

These reversals aren't split-second flips, and instead occur over hundreds or thousands of years. During this lengthy stint, the magnetic poles start to wander away from the region around the spin poles (the axis around which our planet spins), and eventually end up switched around, according to Cornell University astronomers.

10.Earth once had two moons?

Earth may once have had two moons. A teensy second moon — spanning about 750 miles (1,200 km) wide — may have orbited Earth before it catastrophically slammed into the other one. This titanic clash may explain why the two sides of the surviving lunar satellite are so different from each other, said scientists in the Aug. 4, 2011, issue of the journal Nature.

11.Rocks can walk

Rocks can walk on Earth, at least they do at the pancake-flat lakebed called Racetrack Playa in Death Valley. There, a perfect storm can move rocks sometimes weighing tens or hundreds of pounds. Most likely, ice-encrusted rocks get inundated by meltwater from the hills above the playa, according to NASA researchers. When everything's nice and slick, a stiff breeze kicks up, and whoosh, the rock is off.

12.Coral reefs are the largest living structures

Coral reefs support the most species per unit area of any of the planet's ecosystems, rivaling rain forests. And while they are made up of tiny coral polyps, together coral reefs are the largest living structures on Earth — a community of connected organisms — with some visible even from space, according to NOAA.

13.The Mariana Trench is the deepest spot

How low can you go? The deepest point on the ocean floor is 35,813 feet (10,916 meters) below sea level in the Mariana Trench. The lowest point on Earth not covered by ocean is 8,382 feet (2,555) meters below sea level, but good luck walking there: That spot is in the Bentley Subglacial Trench in Antarctica, buried under lots and lots of ice.

14.We're losing fresh water

As the climate changes, glaciers are retreating and contributing to rising sea levels. It turns out that one particular glacier range is contributing a whopping 10 percent of all the meltwater in the world. That honor belongs to the Canadian Arctic, which lost a volume equivalent to 75 percent of Lake Erie between 2004 and 2009.

15.Earth used to be purple

It used to be purple … well, life on early Earth may have been just as purple as it is green today, suspects Shil DasSarma, a microbial geneticist at the University of Maryland. Ancient microbes, he said, might have used a molecule other than chlorophyll to harness the sun's rays, one that gave the organisms a violet hue, he suggests.

DasSarma thinks chlorophyll appeared after another light-sensitive molecule called retinal was already present on early Earth. Retinal, today found in the plum-colored membrane of a photosynthetic microbe called halobacteria, absorbs green light and reflects back red and violet light, the combination of which appears purple. The idea may explain why even though the sun transmits most of its energy in the green part of the visible spectrum, chlorophyll absorbs mainly blue and red wavelengths.

16.The planet is electric

Thunder and lightning reveal our planet's fiercer side. A single stroke of lightning can heat the air to around 54,000 degrees Fahrenheit (30,000 degrees Celsius), according to educational website Windows to the Universe, causing the air to expand rapidly. That ballooning air creates a shock wave and ultimately a boom, better known as thunder.