> Comparing diameter to radius is a little misleading
Nah. It is comparing a distance with a distance.
Besides I assume more people reading my comment are familiar with the concepts of radius/diameter than the meaning of astronomical units. But now, thanks for your clarification, even the geometrically challenged will have the correct mental model. You never know.
> On the same scale, Pluto is 78 AU and Voyager is 320 AU.
Have to disagree. You take your pocket tape measure, carefully hook the end of the tape on the Sun and slowly walk to Pluto. You read what it says. That is a distance.
Then you walk to the disk, hook one end of the tape on one side (carefully, since it is made of dust) and walk to the other side. That is a distance.
Where do I hook my tape measure to measure 78 AU for Pluto? Orbits are not real. You cannot kick them, you cannot lick them, you cannot hook a tape measure on them.
“See where that planet is? Now imagine how far it will be in 124[1] years in a sun fixed coordinate system!” does not quite have the same impact on me as “See that blob? It is huuuge!”
Doubling the number with Voyager makes even less sense. You cannot even say that you are measuring the antipodal points of its orbit, since it is not orbiting the Sun. So the “diameter” of what are you even talking about there?
1: half of Pluto’s orbital period.
Nah. It is comparing a distance with a distance.
Besides I assume more people reading my comment are familiar with the concepts of radius/diameter than the meaning of astronomical units. But now, thanks for your clarification, even the geometrically challenged will have the correct mental model. You never know.
> On the same scale, Pluto is 78 AU and Voyager is 320 AU.
Have to disagree. You take your pocket tape measure, carefully hook the end of the tape on the Sun and slowly walk to Pluto. You read what it says. That is a distance.
Then you walk to the disk, hook one end of the tape on one side (carefully, since it is made of dust) and walk to the other side. That is a distance.
Where do I hook my tape measure to measure 78 AU for Pluto? Orbits are not real. You cannot kick them, you cannot lick them, you cannot hook a tape measure on them.
“See where that planet is? Now imagine how far it will be in 124[1] years in a sun fixed coordinate system!” does not quite have the same impact on me as “See that blob? It is huuuge!”
Doubling the number with Voyager makes even less sense. You cannot even say that you are measuring the antipodal points of its orbit, since it is not orbiting the Sun. So the “diameter” of what are you even talking about there?
1: half of Pluto’s orbital period.