I take it as a given that most western Europeans have never paused to see Mercury in the sky.
If asked, most could not tell you where to look for Mercury (some would now start on the internet.)
If offered a clue: "What about sunrise and sunset?"
Or even more explicit: "What about sunrise and sunset? Before which or after which?"
Some very few might suggest a deep, shallow mineshaft in daylight - or a full solar eclipse.
Simply: look for Mercury sometimes after sunset in the west or at other times before sunrise in the east.
But why named for Hermes, the messenger? What are these comings and goings of Mercury while Venus and Apollo's sun-chariot are so much more regular and steady?
And what of the appearance of Mercury? IF you were to see Mercury with the aid of a telescope, of what might you become aware? [here, see Epictetus]
Suppose that I show you Mercury in a telescope ... here are the variants for this Anschaung that come to mind (and arise if I set up more than one telescope along the road for neighbours and passers-by.)
Subjective: (holding the subjective lens)
1) 45deg mirror (or 90deg prism)
2) Amici prism
3) straight tube extender
Objective
1) mirror (various overall designs and configurations from simple Newtonian to highly modified)
2) lens (as in the typical "Galilean" telescope)
Mount
free-moving (likely a reflector, but also a small refractor on a ball-head mount)
altitude-azimuth
German equatorial
computerized variants of any of the above three
star-gazer
a digital identifier of the stars, planets and or asterisms at which it is aimed
activity
hand tracking
motor-tracking
the above in combination
variants: monocular or binocular options apply in the above to objective, subjective and star-gazer device.
What will be seen: (general characterization)
reflector - a little fuzzy but with good colour (expecially the planets Mars, Jupiter, Saturn)
refractor - may be quite sharp image, but may have violet fringe if not using hydrogen filter
What will be seen: (shape)
The two inner planets, Venus and Mercury, are subject to what might be described as "lunar" phases: they are moon-like in appearance.
Sceptic: how do you know it is not a star?
Answer: under magnification it increases in size as a disk: many stars under magnification do not change their "aspect" notably or else may even reveal themselves to be double or even triple stars (and if the tube is tapped lightly, trace clear distinct sinusoidal paths in which each star is clearly distinguished by a fine "parallel" path with the others - a case of movement in observation)
Richer answer: it will visibly have moved against the starry background by tomorrow
Jupiter answer: watch the weather change and moons appear and shadows pass over its face.
But not Veuns and Mercury. Every 16 years Mars displays its ice caps. But not Venus and Mercury.
Where in lies the scientific/social division-of-labor in the apperception of Mercury.
The observer tends to need to be coached: "Yes, bigger in the view than the star I just showed you - but how would you describe that shape? What does it remind you of?"
Next task: explain away the violet halo.
Next task: explain why the image is inverted up-side down or mirror-reversed.
"See, in this telescope the crescent of Mercury is 'looking down' towards where the sun has set - see?"
"Notice that in this telescope Mercury is 'looking up to the right' but the sun has set down to the left... Let's look at the cresent moon up there in each telecope ... and compare what you see in the scope to what you see with these binoculars ..."
And where is the cresent moon if it is just after sunset? I hope you do not look up, or worse, east ... And which way is it facing ...
Any introductory course in college astronomy should be paired with a course in philosophy. Ditto for botany. Chemistry. Any introductory college course in physics should require one evening learning to look at the night sky. Otherwise how shall we reply to the attacks on reason, Galileo, naturalism and modernity? How else shall we defend observation over prejudice if there is no "foundation" in the actual experience of the student? Next topic: the lunar illusion and the rising full moon.
a note on mathesis in praxis: even the use of the alt-azimuth and the equatorial mounts do not - in use - require mathematics or measurements or numbers or compass points (although the equiatorial mount will be easier to use of faced north and with an angle approximately that of the latitiude of the observer's location.
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What is missing in the propaedeutic to any phenomenology of seeing Mercury in the post-Galilean modern world is a poem, a painting or a sculpture: the "crescent" of Mercury is a real occasion for excitement!
ReplyDeleteQuestion for internet astronomy: the view of Mercury in April, 2010 from Santiago de Chile versus Minneaplois, Minnesota - what the same and what different?
Heidegger may have been ignorant of the role of astronomic sightings in both Islam and in the spiritual life of Australian Aborigines (to mention only two topics)
ReplyDeleteGabriel Marcel in "Tragic Wisdom and Beyond" places the burden on the atheist philosopher.
ReplyDeleteThis is his fallacy:
"What the Copernican astronomer does is to substitue for the geocentric hypothesis another hypothesis ..."
No. Whatever the new hypotheses may have been at one time, facts emerged. The orbit of Mercury lies within the orbit of Venus. The center of mass lies within the diameter of the sun. That there may be non-Euclidean geometries has long been a fact.
Creationists like to say that the evolution of plant and animal species on this planet is a hypothesis or that it is a hypothesis that the earth and sun are over 5000 years old. These may once have been hypotheses: they are now facts.
Denying the age of the sun had been a major step in any-Darwin arguments: nothing of that mass could "burn" for over 5000 years.
Wrong. It does not "burn" (oxidation). Some solar hypotheses of Hoyle, Gamow and others are now established fact.
That the moon is made of material from the original planet earth was a hypothesis: it is now a fact.
The failure to teach evolution has a close parallel in ignorance about basic astronomical facts.
The place to start is with a theory of experience: grounds, objects, perspectives, attributes, relations and transitions. Otherwise knowledge can always be confunded with myth, ideology and bias. Astronomy is not just a language game. An approaching asteroid is not trying to tell us something.
Two binary stars rotate about their common center of mass. Ask the man on the street how common he thinks they are ...