Re: A couple of questions.
- From: eugene@xxxxxxxxxxxxxxx (Eugene Griessel)
- Date: Sun, 13 Aug 2006 07:31:22 GMT
"Imagicka" <Imagicka23@xxxxxxxxx> wrote:
First: Why is it that we only see one side of the moon? That would
mean that it's rotational orbit around itself...is the same length of
time that it takes to orbit around the earth. Which is what? 28.1 days
or something like that? -- Is this why people think that the moon was
once a part of the earth? Are there anymore natural satellites (moons)
around other planets that have the same feature? -- Is there a site
with charts of these orbital information?
The moon is just a little too close and a little to small to break
free of the earth's gravity and establish an independent rotation.
Basically it is trapped or locked by the earth in the axial rotation
it now finds itself in. And I guess the same conditions would apply
to other moons in the same sort of position.
Also, is there a list of the number of stars that we can see in the
night's sky, charted by light polution? How many can we see in the
night's sky with the naked eye?
It depends on a number of factors - where you are being the first -
not only location but altitude and time, secondly your personal visual
acuity and thirdly pollution factors other than light such as aerosols
and smoke.
Obtain a list of stars ranked according to their visual magnitude -
tick of those observable from your personal viewing site, a
planisphere is helpful here or one of the many computer programs
available. Then start working your way upwards from the 6th magnitude
stars (or downward from 1st magnitudes) until you can see one - and
the rest should then be naked-eye visible. Given fair conditions you
should be able to see around 2000 - but in a modern urban environment
this could be lower than 200!
Eugene L Griessel
Never test for an error condition you don't know how to handle.
.
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