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Zamedy
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Does anyone know if there is any internationally agreed method for determining where zero degrees longitude is when mapping other planets etc.?
For some planets, like the gas giants, it's not clear that you could map them in a fashion similar to what has been done on earth, because there are no fixed features or other reference points to use.Does anyone know if there is any internationally agreed method for determining where zero degrees longitude is when mapping other planets etc.?
There are ways of writing things in scientific journals and saying things in hallways that indicate that the authors / speakers think their opponents are a bunch of morons without using a single derogatory term
For some planets, like the gas giants, it's not clear that you could map them in a fashion similar to what has been done on earth, because there are no fixed features or other reference points to use.
Most of the probes sent to other planets in the solar system were designed to photograph these bodies as they flew by. There have been probes sent to the moon, Mars, Venus, and Mercury which went into orbit around those bodies. Because actual exploration of the surface may be impossible or very remote in the future, the concentration of data gathering for those missions was to collect physical data about each body, like whether there was a magnetic field, etc., rather than setting up a surface navigation system.
https://en.wikipedia.org/wiki/Exploration_of_Mercury#Missions
Perhaps in the future, it may be appropriate to devise some sort of mapping convention, but for now, just getting a glimpse of these bodies up close and taking photographs has been sufficient.
In the meantime, you can access Google Mars and Google Moon, which are similar to Google earth.
Your 180 km figure corresponds to roughly six degrees. A minute of arc is 1/60th of a degree. A minute of arc represents about 500 meters on the surface of the Moon. (I wrote "about a minute of arc." The actual discrepancy between Moon ME and Moon PA coordinates is about 860 meters at the surface.)As for the moon coordinates - it beggars belief that these well-educated logical creatures still can't decide one way or the other.
A minute arc would be about 180km on the surface of the moon - that's quite a hike if they get it mixed up!
Your 180 km figure corresponds to roughly six degrees. A minute of arc is 1/60th of a degree. A minute of arc represents about 500 meters on the surface of the Moon. (I wrote "about a minute of arc." The actual discrepancy between Moon ME and Moon PA coordinates is about 860 meters at the surface.)