[geocentrism] Re: The resolution of Mars
- From: "Jack Lewis" <jack.lewis@xxxxxxxxxxxx>
- To: <geocentrism@xxxxxxxxxxxxx>
- Date: Tue, 27 Nov 2007 19:21:15 -0000
Dear Neville,
I look forward to reading the updated version.
Jack
----- Original Message -----
From: Neville Jones
To: geocentrism@xxxxxxxxxxxxx
Sent: Tuesday, November 27, 2007 6:19 PM
Subject: [geocentrism] Re: The resolution of Mars
-----Original Message-----
From: art@xxxxxxxxxx
Sent: Wed, 28 Nov 2007 01:40:04 +1100
Okay, Jack.
My previous posts on this subject still stand.
I'll comment on a couple of the statements of Neville's that you included.
Neville: Mars is not emitting visible light any more than the coin is.
Regner: True. Both just reflect sunlight.
BUT: Mars' surface area is some 1e17 (= 10^17 = 1 followed by
17 zeroes) times larger than a coin. The surface area of Mars'
which is presented to the Sun is 1e17 times larger than for a
coin. Granted the coin have a larger reflectivity (albedo)
close to 1, and Mars' is about 0.15 - so that gives us a factor
of 10. Also, Mars is farther from the Sun, than Earth is, so the
sunlight will be diluted by the square of that factor = 2.3. To
be generous I'll call those two a factor of 100 resulting in the
coin still being 1e15 times dimmer than Mars.
If we placed a coin next to Mars, Mars would be 1e15 brighter
than the coin.
Light that is emitted or reflected in all directions, will get
diluted by the square of the distance. This means that if you
look at a coin a meter away, glinting in the sunlight, it will
be between 1e6 and 2e7 brighter than Mars, depending on the relative
orbital positions of Mars and Earth.
If you put the coin at between 970m and 4.7km away from you, Mars
and the coin would be the same brightness - provided you catch the
glint. The coin would now have an angular diameter between 0.88-4.25
arcseconds - well below the resolution limit of your eye.
Another point, of course, is that you wouldn't be able to see the
coin because you would have to be on the dayside of Earth to get a
reflection off the coin, which means the general daylight will
completely outshine the coin seen at that distance - just as we
can't see Mars in the daytime sky.
Agreed.
I agree with everything else that Neville says, except his statement that
you can't see things that are below the resolution limit.
I would like to add, though, that his statement is correct in sun-lit
scenarios, where the contrast between objects is much lower than between
the black Universe and a star or a planet, e.g., you will be able to see
(not necessarily resolve - they might just be little dots) black letters
on a white background at much larger distance than yellow letters on a
white background.
Agreed.
My example with the airplane is good, since you know the size of the
lights and approximate distance to the plane. I'll estimate the lights to
be about 10cm in diameter, which means that planes more than 350m away will
have lights that are below the resolution limit of your eye (I have used
the 1 arcminute measure that Neville also prefers - the diffraction limit
of 24" is too optimistic).
I hope this helps.
Regner
Agreed. The whole issue is resolution. This is why the article needs slight
modification/correction. Neville.
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