Space Systems!

If you spend a few hours outside your house, you will discover that your Nature is a complex collection of things that work together. Sometimes they might help to create a beautiful day. At other times, they can unleash frightening storms, lightning and tornadoes. Scientists call these things systems because, as they operate through time and space, they can also cause matter and energy to move around within the Earth, and its atmosphere. Like the gears in a watch, some systems can be divided into what are called 'sub-systems', which exchange energy and mass to make up the overall larger system. Every system usually has one or more inputs, and one or more outputs. Let's have a look at some 'systems' that you can find around the house!

Introduction: Your family car is a system of mechanical, electrician and chemical parts that work together to convert chemical energy locked up inside a fuel (gasoline) into mechanical energy (motion). Every system has things called 'inputs' and 'outputs'. In your family car, the gasoline in the tank is an energy input to your car. The output of your car is the conversion of this input (gasoline) into motion. When you turn on the car radio, it has two inputs. The first is the electricity that runs the radio; the second input is the radio signal it picks up from the antenna. The output is the motion of the speaker which converts the electrical and radio energy into sound. Cars, like many other systems, can be further divided into 'sub-systems' that carry out the different steps in making an output from an input.

Sub-systems help the car to use electricity to run its many parts (the electrical system), or keep the engine cool so that it doesn't break (the cooling system). Each of these sub-systems has its own input and output. For example, the input to the electrical system is the car's battery. The output to this system is a variety of devices (distributor, voltage regulator etc) that make the motor run properly (for instance the electrical sparks in the spark plugs)

A Familiar System The most well known natural system to most students is the atmosphere. It receives inputs from the Sun in the form of solar energy and from the ground in the form of heat. It produces as its 'output' a number of phenomena such as weather, surface erosion, winds, and evaporation. We can take one of these outputs, such as evaporation, and see how it is caused by a 'sub-system' called the Water Cycle. Ocean water is heated and evaporates into the atmosphere. This moist air condenses into precipitation (for example rain or snow) and falls to the ground, where it is returned to the ocean in rivers. We can look at each of these steps in the Water Cycle and see that they can also be further divided into even smaller systems that depend on them. Fresh water flowing on the land, for instance, is an important source of energy and sustenance for many living systems that depend on rivers and creeks for nourishment and for transportation.

Other Systems: Most natural systems tend to be hard to study because their components are usually hidden from direct view, or are invisible to the normal senses. They can be too small to see, or sometimes so big that you cannot see the whole thing all at once to see it working. A common watch looks simple from the outside, but as a system it is actually complicated.

[Left Image] A battery or spring provides the energy (input) to drive the gears that help you tell time (output). What happens inside the watch between the battery you can replace, and the dials on the front, is hidden from view.

[Right image] The electronic circuitry inside your TV set is also a 'mysterious' collection of pieces that don't tell us directly exactly what they are doing - only the engineer that designed the circuit really understands all of the details!

Space Systems: We can take an even bigger view of what is going on, by thinking about the way that the Sun interacts with Earth in space. The Sun is its own complex system that generates light, and streams of particles flowing out from the Sun's surface into space.

Sun System: The input to this system is the energy produced in its million-degree core. The output is all of the many phenomena we see on its surface (sunspots, CMEs, magnetic fields and solar winds).

Earth System: The Earth is also its own system, but its is connected to the Sun. The input to the Earth is the light energy from the Sun, the particles from the solar wind, and the particles and magnetic fields from passing CMEs. The output from the Earth's Space System is the aurora, the magnetic storms, the Van Allen belts and the many different electrical currents that flow in space near Earth and in its outer atmosphere.

If we wanted to, we could trace the outputs from the Earth Space System deep into Earth's atmosphere where they become some of the inputs for many different atmospheric systems! Scientists are hard at work trying to trace all of the many inputs and outputs of the many sub-systems that make up the Sun-Earth interaction.

 The sketch below shows how the Sun System and the Earth System are connected together.


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