by neufer » Wed Oct 31, 2012 3:49 pm
Chris Peterson wrote:neufer wrote:
Phobos is in an elliptical orbit such that the height about the Martian equator varies from 5840 km to 6123 km.
~5800 km is the best "closest" approach number
whereas ~6000 km is the best average number.
If I may be a little pedantic here...
all closed orbits are elliptical.
http://en.wikipedia.org/wiki/Argument wrote:
Elliptical arguments: <<Often an argument is invalid because there is a missing premise--the supply of which would render it valid. Speakers and writers will often leave out a strictly necessary premise in their reasonings if it is widely accepted and the writer does not wish to state the blindingly obvious. Example: All metals expand when heated, therefore iron will expand when heated. (Missing premise: iron is a metal). On the other hand, a seemingly valid argument may be found to lack a premise – a 'hidden assumption' – which if highlighted can show a fault in reasoning. Example: A witness reasoned: Nobody came out the front door except the milkman; therefore the murderer must have left by the back door. (Hidden assumption- the milkman was not the murderer).>>
Chris Peterson wrote:
The reason that Phobos's distance from the surface varies is because the eccentricity of its orbit is greater than zero.
Eccentric, a. [F. excentrique, formerly also spelled eccentrique, fr. LL. eccentros out of the center, eccentric, Gr. ; out of + center.]
4. Not coincident as to motive or end.
- His own ends, which must needs be often eccentric to those of his master. Bacon.
5. Deviating from stated methods, usual practice, or established forms or laws; deviating from an appointed sphere or way; departing from the usual course; irregular; anomalous; odd; as, eccentric conduct. This brave and eccentric young man." Macaulay.
- He shines eccentric, like a comet's blaze. . Savage
[quote="Chris Peterson"][quote="neufer"]
Phobos is in an [b][u]elliptical orbit[/u][/b] such that the height about the Martian equator varies from 5840 km to 6123 km.
~5800 km is the best "closest" approach number
whereas ~6000 km is the best average number.[/quote]
If I may be a little pedantic here... [i]all [/i]closed orbits are elliptical.[/quote][quote=" http://en.wikipedia.org/wiki/Argument"]
Elliptical arguments: <<Often an argument is invalid because there is a missing premise--the supply of which would render it valid. Speakers and writers will often leave out a strictly necessary premise in their reasonings if it is widely accepted and the writer does not wish to state the blindingly obvious. Example: All metals expand when heated, therefore iron will expand when heated. (Missing premise: iron is a metal). On the other hand, a seemingly valid argument may be found to lack a premise – a 'hidden assumption' – which if highlighted can show a fault in reasoning. Example: A witness reasoned: Nobody came out the front door except the milkman; therefore the murderer must have left by the back door. (Hidden assumption- the milkman was not the murderer).>>[/quote][quote="Chris Peterson"]
The reason that Phobos's distance from the surface varies is because the [i]eccentricity[/i] of its orbit is greater than zero.[/quote]
Eccentric, a. [F. excentrique, formerly also spelled eccentrique, fr. LL. eccentros out of the center, eccentric, Gr. ; out of + center.]
4. Not coincident as to motive or end.
[list][b][i][color=#0000FF]His own ends, which must needs be often eccentric to those of his master.[/color][/i][/b] Bacon.[/list]
5. Deviating from stated methods, usual practice, or established forms or laws; deviating from an appointed sphere or way; departing from the usual course; irregular; anomalous; odd; as, eccentric conduct. This brave and eccentric young man." Macaulay.
[list][b][i][color=#0000FF]He shines eccentric, like a comet's blaze. .[/color][/i][/b] Savage[/list]