what is a system? how is the earth a system?

Answer 1

A system is that which contains entities that interact or is dependent on each other for the proper functioning of a whole.

Solar system is called so, because even though we are talking about solar (sun), it is a system that has planets, dwarf planets, and asteroid belt which keep the things in its current places and orbits due to force of gravitation.

Coming to your question on Earth as a system. Earth is a system since it has a ecology, the entities of which are interdependent. Thats why its called Ecosystem.
Bacteria is eaten by smaller sea creatures, smaller sea creatures eaten by bigger, bigger eaten by still bigger, and the waste of the bigger creatures dissolve in water and becomes food for bacteria and the cycle goes on. Carbon cycling is the most important thing that happens in ecosystem. Destroying one element will read to ripple effect and we dont know how the system will crash.

Answer 2

A system is a combination of element that interact with each other in such a way that if you want to understand a problem, then you have to look at all the elements.

For example, to understand tides, you have to look at Earth, the Moon and the Sun as forming a system (the other planets do not have a measurable effect on our tides).

There are some problems for which a lot of Earthly things have an impact. For example, energy transfer and Earth temperature.

Consider the Earth as a system in a directional flow of energy of 1370 Watts per square metres.

Using the Earth's diameter, you can calculate how much of that energy is intercepted by Earth. You can also calculate how much of that is reflected back to space without being absorbed (mostly by clouds) and have a ratio that represents all the effects put together, as if it were Earth itself that reflected the light. The ratio is called "albedo" and for Earth, we use approximately 30%.

So you could calculate every individual effects (clouds, oceans, forests, ice caps...) or treat Earth as a "system" that reflect 30% of the energy it receives.

Some energy is absorbed and stored in ways other than heat. The most common example is complex molecules, such as chlorophyll. However, that is not much (less than 1%). More energy goes into making the air move (wind), evaporating water (more clouds, then rain, then rivers that run back to the sea).

But, in general, the energy that does not get reflected eventually turns up as heat. So, instead of looking at individual elements using the energy, we look at Earth as a system that absorbs 70% of the energy from the Sun in the form of heat.

This means that Earth must be capable of radiating away an equal amount of energy (otherwise, it would get hotter and hotter without bound).

We can calculate what temperature the Earth must be to generate that amount of energy from its entire surface (not just the surface that captures the sunlight). Turns out to be a few degrees above the freezing point of water (this is very fortunate for us living beings).

We can do this because we take Earth as one "system" instead of trying to calculate every minute detail (how much heat is absorbed by air, by water, by sand, by grass, by trees, by rain...)

Answer 3

A system is a group of entities that inter act with each other.