Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: neilep on 18/02/2008 20:52:40
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Dear All.....How are You ?....Ok ?...good !....thanks for the chat !!
The sun is just over 400 times the diameter of the moon yes ? and is coincidentally just over 400 times as far away...this is why we get total eclipses of the sun yes ?
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Is this coincidence extraordinary in the extreme ?......is it possible to calculate the odds that a planets moon has this unique size ratio thing going on with the systems sun ?
Thanks
Neil
xxxxx
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It is how things are today, but it was not always so - there used to be a time when the moon was closer, and in the future it will be further away. In the future, we will not be able to have full solar eclipses.
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It is how things are today, but it was not always so - there used to be a time when the moon was closer, and in the future it will be further away. In the future, we will not be able to have full solar eclipses.
DOH !!!
I knew that too !!
Though I suppose our moon could have been so small that it could never have been able to eclipse the sun...even when it was so close...........
.....also......*digging my own hole here*........planets which are farther away from the sun probably enjoy solar eclipses all the time yes ?...cos the sun is a lot smaller ?.......or does the definition of an eclipse mean that the intervening body has to cover the object precisely ?
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I have no idea what the actual probability is but it does seem quite unlikely if you consider planets in general. However it may not be quite so unlikely for planets with intelligent life like ours when you consider the position of the planet with respect to the host star to get the temperature riight and the value of a large moon as a tide generator and evolution pusher in developing life.
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.....also......*digging my own hole here*........planets which are farther away from the sun probably enjoy solar eclipses all the time yes ?...cos the sun is a lot smaller ?.......or does the definition of an eclipse mean that the intervening body has to cover the object precisely ?
There does not have to be a precise match, otherwise you could not have a lunar eclipse (since the Earth is larger than the Moon, but obviously the Earth is as far away from the moon as the Moon is from the Earth, so the Earth looks larger from the Moon than the Sun does).
Our moon is the fifth largest moon in the solar system, so many of the other moons might just be too small. The 4 larger moons are all of Jupiter of Saturn.
Given the large number of moons that some planets have, the question may be is there any time when the Sun, over some part of its surface is not eclipsed by one or other of its moons.
Given that Jupiter is about 5 times as far from the Sun as we are, it seems that maybe at least 4 of its moons could obscure the sun.
Saturn is around 9 to 10 times our distance from the Sun, it probably has around 7 moons which could obscure the Sun from some point on the surface.
Uranus is about 20 times our distance from the Sun, again, I count at least 7 moons of sufficient size and proximity to the surface.
The Earth is actually the only one of the inner planets that does have solar eclipses, but the only other inner planet that even has moons is Mars, and they are fairly puny moons at that. We are actually, in that respect, quite anomalous.
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The probablity of it happening is one. It happened and we are on the example.
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I been wonder this, and deeply appreciate the wonderful creation.
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Dear All.....How are You ?....Ok ?...good !....thanks for the chat !!
The sun is just over 400 times the diameter of the moon yes ? and is coincidentally just over 400 times as far away...this is why we get total eclipses of the sun yes ?
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Is this coincidence extraordinary in the extreme ?
Moon was put in that position by aliens who wanted ancient "clergymen" on earth be able to predict solar eclipse.
hmmm...not sure [;)]