They have images of the probe.
Take a look at those images. They're trying to deduce a whole lot out of perhaps 10 pixels. If they has dropped a Vespa on the surface from 1 km up, it might look the same.
CRTs run up against fundamental laws of physics. One is focusing, bright screens require a lot of electrons per unit time and electrons repel each other. Getting them into a small place (sharp focus) is difficult at best. Another is atmospheric pressure, at 1 ton per square foot big screens need thick glass if they're curved and VERY thick glass if they're flat.
With CRT phosphors, there's always some compromise between ghosting and flicker, and one can't be completely eliminated without worsening the other. There's some possible improvement available with high refresh rates, but before long a high refresh rate multiplied by the number of pixels on the screen results in an unacceptable rate for modulating an electron stream. (This can be reduced with multiple electron guns, but that introduces alignment problems and huge costs.)
All in all, something like a 40" 4k CRT would be enormously expensive, heavy, and a maintenance nightmare.
It's common practice to provide drawings for many of the more basic nouns, and acorn is a prime example.
To establish a language in a logical manner, something has to be tied to reality. An effort to make a language out of words solely defined by other words is circular, baseless, and futile. Some things must be identified by pointing (illustration) and acorn is a good place for a root.
Essential qualities in a definition are identifying the category to which the word belongs, and the distinguishing characteristic(s) that separate the word from other words in the category. In most contexts, a minnow is a "small fish".
You might not even notice if you ate a single minnow. Scoop 'em up and fry them in hot oil by the bucketful.
The latter is the more honest way of doing it
Such as redefining "liberal" to mean "gun-toting thief who insists that every be disarmed"?
One man's constant is another man's variable. -- A.J. Perlis