Although we call it home, it is after all, another of the planets in our solar system so let’s check out Terra.
Here are a list of Fun Facts I’ve compiled about Earth:
Composition of Earth is roughly as follows:
32% iron; 30% oxygen; 15% silicon; 14% magnesium; 3% sulfer; 2% nickel; 1.5% calcium; 1.4% aluminum
This makes Earth the densest planet in the solar system! Lots of that iron and nickel is concentrated at the core and is highly compressed, radioactive, hot and molten. Earth’s innards interact to create a reasonably strong magnetic field that protects us from solar influences and in short, makes this place a cozy home for us and all other living things. Without this magnetic field, we’d be toast.
The Earth’s magnetic field is believed to be generated by electric currents in the conductive material of its core, created by convection currents due to heat escaping from the core. However the process is complex, and computer models that reproduce some of its features have only been developed in the last few decades. The Earth and most of the planets in the Solar System, as well as the Sun and other stars, all generate magnetic fields through the motion of highly conductive fluids. The Earth’s field originates in its core. This is a region of iron alloys extending to about 3400 km (the radius of the Earth is 6370 km). It is divided into a solid inner core, with a radius of 1220 km, and a liquid outer core. The motion of the liquid in the outer core is driven by heat flow from the inner core, which is about 6,000 K (5,730 °C; 10,340 °F), to the core-mantle boundary, which is about 3,800 K (3,530 °C; 6,380 °F). The pattern of flow is organized by the rotation of the Earth and the presence of the solid inner core.
Earth was originally born as a twin to the planet Theia, which was about half as wide as Earth and roughly the size of Mars. The two planets shared an orbit for several million years until they collided. Earth absorbed Theia, and the remaining debris eventually coagulated into Earth’s moon. The mass donated by Theia gave Earth the gravity necessary to sustain a substantial atmosphere. http://facts.randomhistory.com/2009/09/17_earth.html
Diameter of Earth is 12,756 km (7,926 miles). Distance from the sun is 91 million miles at perihelion and 94.6 million miles at aphelion. Today Earth is at perihelion! http://earthsky.org/space/are-the-december-solstice-and-the-january-perihelion-related
Orbital speed is 66,660 mph! We are traveling!
Seasons are caused by Earth’s tilt:
Seasons: When Earth is at its portion of orbit around the sun where the North Pole is pointed toward the sun, that is northern hemisphere summer. When we travel around in our orbit to the other side of the sun, it is Northern Hemisphere winter. Interesting that we are closest to the sun in January, but it’s winter here in America!
70% of the surface of Earth is covered by oceans – most of the oceans and ocean floors have yet to be explored; Earth is actually a water-world. We are not entirely sure where all the water came from either. It has been conjectured (an educated guess…) that comets delivered the water…speculation at best and recent discoveries from exploring comets have failed to conclusively confirm this conjecture. I for one am grateful for the oceans, because they cause beaches:
Of all planets, Earth is not named after a Greek or Roman god, goddess or other entity. The word “Earth” developed from a wide variety of Middle English forms, which derived from an Old English noun most often spelled eorðe.
78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. The atmosphere has a mass of about 5.15×1018 kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The Kármán line, at 100 km (62 mi), or 1.57% of Earth’s radius, is often used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi). Several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition. http://en.wikipedia.org/wiki/Atmosphere_of_Earth
And as far as anyone has been able to tell, Earth is the only planet with life. According to the best guesses we have, Earth is about 4.5 billion years old; and researchers think some sort or primitive life first appeared (how is anyone’s guess!) about a billion years later. This stuff was mostly just single-cell primitive life. Then life exploded:
…between about 570 and 530 million years ago, a burst of diversification occurred, with the eventual appearance of the lineages of almost all animals living today. This stunning and unique evolutionary flowering is termed the “Cambrian explosion,” taking the name of the geological age in whose early part it occurred.
570 million years ago is a long, long time ago, and more than likely, there were all kinds of living things leading up to that time and what we know about the Cambrian Explosion comes from a fossil record that is spotty at best. Google Burgess Shale. We really don’t know that much about what it was really like 570 million years ago. But we do know enough to make up awesome graphics and that’s pretty cool if you ask me!
Humans? According to the best research of our day, we haven’t been around all that long – something like 2.3 to 2.4 million years. And as far as we have found, the earliest civilizations didn’t start happening until 4000 BC; so we are real new-comers.
Earth has a single moon. I’ll cover the moon in a later post.