Your Blue Home
The third planet from the Sun is your home. The Earth is the only known planet where life can survive. As far as we know, there is no other planet in the universe like Earth. We have a very narrow temperature range that allows water to remain a liquid. Life has developed over millions of years because of that liquid. What else makes us special? Most of our atmosphere is made of nitrogen (N), a relatively inert gas. If we had clouds of sulfuric acid or methane (like other planets), life may have never developed.A Surface That Floats
There are also huge landmasses on our planet. The rock plates that float across the surface are called tectonic plates. Those plates float on the liquid region called the mantle. The mantle is an area between the core and the crust that is filled with molten rock. It is kept in a liquid state because of the energy given off by the center (core) of the Earth. Scientists have also discovered that pressure increases as you move towards the center of the planet. The core of the Earth has extreme temperatures and pressures that keep the iron (Fe) and other metals liquid and flowing.Magnetic Field Armor
Flowing metal in our planet helps create something called a dynamo effect. Dynamos create large magnetic fields. In the case of the Earth, the magnetic field protects our planet from space. This protective cover is called the magnetosphere. It shields us from the solar winds and solar radiation. You can see where solar winds and the magnetosphere collide when you see the Aurora Borealis (northern hemisphere) and the Aurora Australis (southern hemisphere).Built For Life
Although many planets in the Solar System have atmospheres, ours protects us from space and encourages life. With an atmosphere made up of 78% nitrogen (N), 21% oxygen (O), and 0.03% carbon dioxide (CO2), life has thrived on this planet. Our atmosphere has many layers divided by different temperatures and pressures. The atmosphere also provides the planet with protection. The ozone (O3) that surrounds Earth filters out ultra-violet light. The density (thickness) of the atmosphere helps to vaporize many solid particles colliding with the planet. As you can tell, the atmosphere serves many purposes.
More Than Planets
If you finished the main Solar System section, you now understand that our system has one star and eight accepted planets. Given that basic information, we want to let you know that there is much more in our little system than those nine objects.What You Can See
Sure, you can see a planet. They are tough to miss. As you continue exploring, you will find moons around almost every planet. While the Earth only has one, other planets have more than twenty moons. You also know that you can see rings made of small pieces of dust and ice that circle Saturn and other gas giants.As you look for smaller objects in the system, you will find a field of asteroids in orbit around the Sun between Mars and Jupiter. There are also stray asteroids flying through the Solar System. Comets are also found orbiting the Sun. The amazing thing is that there may still be other objects in our Solar System. That's one of the exciting things about astronomy... There are still millions of things to discover in the universe.What You Can't See
There are also many things we can't see in the Solar System. There are small particles and energies swirling throughout the system. Many of these unseen energies are created by the Sun. We have a heliosphere that surrounds our entire system and Voyager has just reached the heliopause (the edge). The Sun also gives off small particles called the solar wind, light, and various types of radiation. While Earth needs to be protected from some of these forces, the energy that creates the heliosphere is protecting every object in our system.
