Before Vectors, was it Components, and Quaternions?

In summary, before the introduction of vectors by Gibbs & Heaviside, physicists used quaternions as a means of extending complex numbers into a three-dimensional space. However, quaternions were not very popular among physicists and were eventually replaced by more complex algebras for understanding special relativity. Gibbs' simplified development of quaternions led to the familiar vector calculus, which works well in two or three dimensions but cannot be generalized to higher dimensions. This is why Maxwell's original equations, which used quaternions, were later condensed into a more compact form using vector calculus.
  • #1
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What did physicists use before the introduction of vectors by Gibbs & Heaviside, was it the exact same as we would use when denoting components with an x or y subscript or something completely crazy?

Also, I've read in quite a few places that quaternions are very useful for things like Special Relativity & in particle physics & I've definitely seen them being used quite a lot in Lie Algebra texts as I've browsed through. How hard are they, i.e. what makes them so crazy & what are the prerequisites?

The only bad thing I know about them is that it took Maxwell 20 Quaternion equations to convey what Hamilton was able to condense into 4, (or 8 in a sense...).
 
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  • #2
I, too, am interested in knowing how physicist dealt with their concepts before the advent of vectors.
 
  • #3
Not too well, IMO, which was why vectors were invented in the first place.

Quaternions were originally developed by Hamilton as a means of extending complex numbers into a three-dimensional space from the well-known complex plane.

http://en.wikipedia.org/wiki/Quaternion

Physicists were somewhat underwhelmed by using quaternions, and they fell into disuse for most tasks. More complex algebras than quaternions were needed for things like understanding special relativity. A simplified development of quaternions led to the familiar vector calculus of Gibbs. Vectors work well at describing what happens in two or three dimensions, but they cannot be generalized to higher dimensions.

http://en.wikipedia.org/wiki/Vector_calculus

This is how Maxwell's equations looked in their original form:

http://upload.wikimedia.org/wikiped...mical_Theory_of_the_Electromagnetic_Field.pdf

The modern differential forms of these same equations are much more compact:

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/maxeq.html#c3
 

Related to Before Vectors, was it Components, and Quaternions?

1. What are components and how are they related to vectors?

Components are the individual parts or magnitudes that make up a vector. They are usually represented by the x, y, and z values in a 3-dimensional coordinate system. Vectors are composed of components, with each component representing the magnitude in a specific direction.

2. How are components and quaternions different?

Components and quaternions are both mathematical representations of vectors, but they differ in their complexity and use. Components are simple and commonly used in 3-dimensional space, while quaternions are more complex and used in 4-dimensional space. Quaternions also have additional properties that make them useful for certain applications, such as in 3D rotations.

3. Why were quaternions developed if components were already being used?

Quaternions were developed in the 19th century by Sir William Rowan Hamilton as a way to represent 3D rotations in a more efficient and elegant manner. Components were limited in their ability to represent rotations, as they often required multiple operations and calculations. Quaternions provided a more concise and intuitive way to represent rotations, making them useful in fields such as physics and computer graphics.

4. Are quaternions still relevant in modern science and technology?

Yes, quaternions are still widely used in various fields such as computer graphics, robotics, and physics. They are particularly useful for representing 3D rotations and orientations, and have advantages over other methods such as Euler angles in terms of stability and efficiency. Many modern software and programming languages also have built-in support for quaternions.

5. Can components and quaternions be used interchangeably?

No, components and quaternions have different mathematical properties and cannot be used interchangeably. While both can represent vectors, they have different operations and transformations. Components are useful for simple calculations in 3-dimensional space, while quaternions are better suited for complex rotations and orientations in 4-dimensional space.

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