This is “on topic” relative to the string’s title, but “off topic” relative to SpaceX.
One way to think about units of measure is to pit imperial versus metric.
Another way to think about units of measure is to imagine how they will change in the future.
Let’s suppose that among the 10 septillion—one followed by 25 zeroes—planets estimated to exist in the observable universe there are a few intelligent species that have been around longer than we have. [medium.com/starts-with-a-bang/how-many-planets-in-the-universe-9153a05bd0d5 cited for planet count .] How would those species measure, for example, distance?
Let’s suppose that there are more than one of these species that are either in contact with other species already or are intending to connect with other species. How can those species best support interstellar conversations?
One of their tools is the simplification of the elements of conversation. One of the elements of conversation is measurement. Measurement requires units of measurement. Units of measurement can be like those used on Earth, like the imperial and metric systems which are Earth-centric and unguessable beyond Earth. Both systems are based on the anachronistic division of the distance from the north pole to the equator. In metric the original distance was redefined relative to light speed to enhance its accuracy, but the underlying measure remains a fraction of an Earth distance.
Units of measure developed beyond Earth won’t relate to Earth’s circumference, but all imaginable forms of intelligent life will have units of measure. Going back to our interstellar communications, what have those lifeforms that are more mature than Humans are, used as a basis for their units?
Suggestion: they have based units such as distances in space and time on features of the universe that are constant to all intelligent life. For instance, spatial distance will be based on the distance from the nucleus of a hydrogen atom to its electron. (I’m ignoring the more accurate rendition of an atom posited by quantum physics and going with the classical Rutherford model.) This distance can be considered one or even one-trillionth of a daily-use unit, but the measurement will be universally available.
Staying with hydrogen, a not unreasonable assumption, then the measure of duration could be the time it takes for a beam of light to travel from hydrogen’s nucleus to its electron. Or time could be based on (what I’m guessing is) the most common naturally occurring radioactive element, uranium-238. Like us, they know its decay rate and can do a progression of half-lifes to a unit that is practical in daily use. And so on.
BTW, Humanity has already started thinking in absolute, universal terms. We measure temperature in Celsius and Fahrenheit, two not unreasonable scales based on water’s most common phase-transition points, but we also measure temperature relative to absolute zero, in units Kelvin. Kelvin isn’t universal in its use of the temperature increase defining one degree, but it is in its setting zero equal to absolute zero. A great first step.
Humans who believe that we will remain Earth-centric forever can be comfortable in their provincial view of the future, but those of us who believe that we will someday interact with other species, likely more intelligent than us, can begin our what-if analysis. Why would we not? In seeking best-case universal options, isn't it likely that we will discover currently unperceivable knowledge? We can begin to consider the natural world and its constants as the basis of measure that our children’s children’s children will be comfortable with. None of those measures will use Earth as a source of definition.
What is the most-natural unit for expressing Coulomb's law? Gravity? Weight? Certainly we're not using any of those units.
Although I first proposed hydrogen as a reasonable focus of defining units of space and time, would other species consider it more reasonable to extract measures from the nature of light? If so, then we can also start populating our notions of what zero means, as in when did the universe begin? We currently use the big bang as our zero, as our starting point, but I suspect the first 100,000 years or so are due for drastic changes in how we understand the period. However, the universe as we understand it has what might be a better beginning date; the moment when matter and energy expanded sufficiently to create light. In the beginning, God said “let there be light.”
How finely can we hone universal time’s zero? For a first attempt, can we define day-one, minute-one, second-one as the moment precisely 300,000 years after the big bang? No, but we can make an educated guess and refine it as we focus on the problem. Our first approximation won’t hold forever, but isn't it better than our current time map that begins 2020 years ago, with it's bizarre plus-and-minus data points?
And what will we discover to replace those silly Babylonian seconds, minutes and hours ? What does nature tell us to use as our divisions of time?
Will the general public accept so outrageous a shift in perceptions as I’m proposing? Of course not, but they don’t need to. Rather, scientists, philosophers and other thinkers must.
How can we begin to simplify our conversations with beings from other stars? Our first effort was beautiful, but the beauty of the Pioneer recordings was conceptual, not practical. Aliens won’t depend on nor expect other forms of life to have ten fingers, so won’t assume base-ten units. Thus, much of the data we sent to them will be initially indecipherable, but the underlying units are binary, and they will certainly understand binary. (They’ll also get a chuckle out of discovering that there are aliens that use something so complicated as is base ten.)
No, we don’t need to think in terms of natural units of measure. Not yet. But remember the reason we lost the probe that we sent to Mars: a couple of highly intelligent, highly competent engineers didn’t make the conversion from metric to imperial.
What will future communication failures cost us?