Which of the other planets is, on average, closest to Pluto?
The word "other" is used advisedly, as there are many who do not think Pluto is a planet. Indeed, the International Astronomical Union decided last week that Pluto does deserves to retain its status as a planet. Pluto is the only planet discovered by an American. Moreover, on Thursday, Feb. 11, the Pluto-Neptune anomaly will end and Pluto will return to its place outside Neptune's orbit.
All this makes the problem a timely one. Some assumptions:
- Planetary orbits are in the same plane and circular (with radius equal to the long-term average distance from the sun: thus the planetary order is Mercury, Venus, Earth, Mars, Jupiter, Uranus, Neptune, Pluto).
- Planets are found in random positions along their orbits.
For advanced space travelers:
Which planet is most likely to be closest to Pluto?
For this you will need the radii of the circles, which I do not have handy I am afraid, though they are easy to find. Michael Schweitzer, who spotted the error in #878, has worked out the probabilities. Hmmm....looking at his results I see that a much better way to phrase this auxiliary problem is:
Which planet is least likely to be closest to Pluto?
And something I have not thought about:
Which planet is most likely to be farthest from Pluto? Which planet is least likely to be farthest from Pluto?
Source: A problem book by Friedland
© Copyright 1999 Stan Wagon. Reproduced with permission.