Questions and Misconceptions about the Earth

Since we all live on this planet you'd think everyone would want to know all there was to know about it and some do, but some people know surprisingly little about our world. It's really a fascinating place. In out next two articles we'll talk of interesting things about our home planet. Did you know all these things?

Is Earth Round?

Well that seems rather obvious, we've seen pictures of Earth taken from the Moon and it certainly looks round, but in fact, it's not. Rotation causes Earth to flatten slightly at the poles and bulge slightly around the equator. Recently, that midriff bulge is growing and scientists think it's due to glacial melting.

Lightning causes Thunder

This too seems obvious because you see a flash of lightning and then hear the thunder, and this time obvious is correct. If you wanted to really nitpick, you could say it's actually the superheated air around the lightning bolt (about five times the temperature of the Sun,) which causes thunder. The sudden heating causes the air to expand faster than the speed of sound, compressing it and causing a shock wave we hear as thunder.

Dust from Space falls to Earth Every Day.

Actually, a lot of space dust falls to Earth every day. The US Geological Service estimates that one thousand tons of dust from space enters the atmosphere and falls to Earth every year! An interesting theory, recently gaining in popularity is Panspermia, theorizes that life itself could have come to Earth via a comet.

What two large US cities are Physically Merging?

The San Andreas Fault is the largest US fault, running north/south in the western US. The two sides are slipping at a rate of about two inches per year, causing LA to move towards San Francisco! No need to worry though, it'll take a good fifteen million years for the cities to meet.

Our air consists mostly of Oxygen.

We're touted as an "oxygen breathing species" right? I've heard it many times, but although we breath oxygen, it isn't the main ingredient in our air. Eighty percent of our atmosphere is made up of nitrogen, not oxygen! Most of the rest is Oxygen, with trace amounts of stuff like argon thrown in.

How much of the Earth's surface is covered by water and how much of that is fresh?

Earth is a water planet: 75 percent of the surface is covered by water, in fact if you photograph Earth at just the right spot, the entire surface looks covered by water! How much of that is fresh water? Not much, only three percent of all the water on the planet is fresh water.

Is Earth's core solid?

It is believed that the innermost part of Earth's core is solid. The outer portions of the core however are believed to be molten. It is estimated that temperatures at Earth's center reach 7000 degrees F. We've never been to the center of the Earth of course, but things like magnetic pole reversals make us believe the Earth's outer core is molten.

What's the Deepest place in the Ocean?

In the Pacific Ocean lies a place called the Mariana Trench which has a depth of 36,198 feet, or 6.9 miles! The Mariana Trench lies south of Japan towards the Mariana Islands.

Well if you haven't been astounded or befuddled by any of these facts about Earth, we'll do this again next week and have another try!

Constellations

The Solar System