In general we expect this to work:
Quantity["Speed of light"] Quantity[1, "SpeedOfLight"]
And it does because it can make use of Wolfram|Alpha.
Oddly, though, when at work this will always timeout for me. The same happens with Entity
when trying to format.
We can replicate it like so:
Block[{WolframAlphaClient`Private`$ AlphaQueryTimeConstraint = .1}, Quantity[1, "Speed of light"] ]
EntityValue::timeout: A network operation for EntityValue timed out. Please try again later. Quantity::unkunit: Unable to interpret unit specification a.
Quantity[1, "Speed of light"]
Despite that, this does work:
WolframAlpha["speed of light", "Result"] Quantity[1, "SpeedOfLight"]
One thing I have noticed is that in my Terminal my hostname is reassigned to a UUID-like string rather than the standard human-readable one Macs provide.
Does anyone know why this might be happening?