A separate base dimension for angles

[sharkdp]

This topic is something up for discussion for future SI standard versions.

Pro:

• [1] Angles in the SI: a detailed proposal for solving the problem, https://arxiv.org/abs/2108.05704
• [2] Angles are inherently neither length ratios nor dimensionless, https://arxiv.org/abs/1909.08389
• [3] Brownstein K R, Angles—let’s treat them squarely, Am. J. Phys. 65 605–14 (1997).
• [4] Dimensionless units in the SI, https://arxiv.org/abs/1409.2794
• [5] On the status of plane and solid angles in the International System of Units (SI), https://arxiv.org/pdf/1810.12057.pdf
• [6] On the dimension of angles and their units, https://arxiv.org/pdf/2203.12392v2.pdf

Contra:

• [6] Dimensional angles and universal constants, https://doi.org/10.1119/1.18964
• [7] M. Grötschel, H. Hanche-Olsen, H. Holden, Comment on ‘Angles are inherently neither length ratios nor dimensionless’.
  (and companion paper https://arxiv.org/abs/2011.05779v4)
• [8] Comment on 'Angles in the SI: a detailed proposal for solving the problem', B P Leonard, https://iopscience.iop.org/article/10.1088/1681-7575/ac5433/meta
  (and reply to comment: https://iopscience.iop.org/article/10.1088/1681-7575/ac5434)

Review:

• [9] Implications of adopting plane angle as a base quantity in the SI, https://arxiv.org/pdf/1604.02373.pdf

[sharkdp]

This can be done today, with a slightly modified Numbat prelude, based on [1] (see above). See draft in #167. Combining this with #55 would be one option to easily expose this to users.

[sharkdp]

See also:

• 1 lumen does not equal 1 candela (1 lm -> cd returns 1 cd) insect#225
• Radians per second to Hertz conversion incorrect insect#50
• Looks like a conversion error between rpm and rad/s. insect#187
• RPM, wrong conversion insect#210