• What is a referral system?
• Reference system example

We explain what a reference system is in physics, what it is for and its different conceptions in classical and relativistic mechanics.

A reference frame can have from one to four dimensions.

What is a referral system?

When we speak of a reference system, we normally refer to a set of conventions that an observer needs, within a physical-mechanical system, to be able to measure the position and other physical magnitudes of an object under study.

This means that a reference frame is the necessary context to understand the dimensions and orientations of an object. For example, if we look at a photo of a dinosaur bone, it is impossible to know how big it is if we lackscale. That is why rulers or objects are placed next to it, to establish a comparison. The latter is a reference model for size.

However, the appreciation of this concept in the physical It depends on the specific perspective from which it is studied:

• In classical mechanics. The reference system is understood to be the orthogonal coordinate system with which we can study a Euclidean space, as occurs in the analytic geometry. For example, the axis of coordinates that make up the meridians and parallels with which we organize imaginatively our planet, allow the construction of a global reference system that today we know as GPS (Global Positioning System) and that uses these imaginary lines as a reference to locate a point within the globe.
• In relativistic mechanics. By reference system we understand the space-time coordinates that identify any physical event of interest, from four vector orthonormal reference: three spatial (height, length, depth) and a temporary one (weather).

Reference system example

Without a reference system we can confuse the dimensions of the objects.

A simple and classic example to understand the use of reference systems is based on a spacecraft that takes off from the surface of the Earth.

For those observing it from the surface, the ship ascends and is soon out of sight, looking smaller and smaller as it moves away. Instead, for the pilot it is the Earth that is left behind, moving away from the ship and getting smaller as it is left behind. For both this movement it will be fast and linear.

But for a third viewer located in theMoon the rocket's motion may appear slow and distant, minimal, barely occurring, and it will only pick up speed as it approaches it on its path. This difference is due to the fact that a different reference system is used in each case.