I Is there a unit system with ##\hbar=G=c=\mu_0=1##?

1,225
75
I understand that one can play with the units. But what about the dimensions? Does time really exist for example? I'm confused.
Ref. my posts #5 and #7, I think dimensions are kept. As for Planck system where time, length, mass, charge, temperature are measured in units of ##t_P,l_P,m_P,q_P\ and\ T_P##, "0.8 time" has magnitude 0.8##t_P## of dimension [T], "0.8 length" has magnitude 0.8##l_P## of dimension [L] , "0.8 velocity" has magnitude ##0.8\ l_p/t_p=0.8\ c## of dimension [L/T] and so on.
 
27,703
4,165
I see I am a little late to this thread.
I'm wondering whether there is an objective notion of what a quantity's units are.
No, the dimensionality of units is a matter of convention for the system of units. This is also closely related to the form of the laws of physics in those units and the dimensionful universal constants.

A good example is cgs units and SI units. The dimensionality of charge is different in the two systems and Maxwell’s equations are different.
 

Want to reply to this thread?

"Is there a unit system with ##\hbar=G=c=\mu_0=1##?" You must log in or register to reply here.

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving

Hot Threads

Top