> Hello Carol,
> carolb wrote:
> > I’d like to comment on the last paragraph. Can you
> > on some of the claims you made here, such as the following:
> > How and by whom was the moon ‘introduced’ into earth’s
> You tell me-if one were so inclined, how would one put an
> orbiting body around a planet? When we terraform Mars 100yrs
> from now and come to the realization it needs a comparable moon
> to support tidal action, stabilize its orbit, and maintain the
> atmosphere we've created-how will we do this? And if I cannot
> answer "how" this means what?
> As far as who, I already suggested "extraterrestrials", but if
> you are seriously asking specifically "who" then I would doubt
> the motive of your questions because obviously this is not
> something I could answer. Could be the Borg or Co-Magmen for
> all I know.
Carol: Why are you assuming the moon was ‘placed’ in orbit by an extraterrestrial agency? Which is more likely to have happened – a group of aliens maneuvered a 2,160-mile diameter body into orbit around earth, or it was formed by collision with a Mars-sized body early in the history of the solar system, when such collisions were commonplace, as evidenced by the pock-marked surfaces of all the rocky planets, moons and asteroids?
As the moon’s composition is similar to earth’s, though in different distributions, are we to assume the aliens knew the earth’s composition beforehand, and manufactured or found a moon that would match the earth in composition?
Are you sure that Mars is going to be ‘terraformed’ 100 years from now? Are you sure we have anything like the technologies, resources or will to do such a thing? Mars orbit is already stable – why would it need another moon to stabilize what is already stable? Where would we get a large moon from?
As for ‘who’ maneuvered the moon into position, no, I didn’t expect you knew who did.
> > The moon is perfect in size and placement – in comparison
> > what, and in relation to what?
> There is nothing to compare it to. No other rocky planet in our
> solar system has one. Kind of the point.
Carol: The point of what?
> In relation to the Earth and the Sun. The Moon is 1/400 the
> size of the Sun and 1/400 the distance from the Earth to the
> Sun. Today it is actually 1/389 but 600,000,000yrs ago it would
> have been a spot on 1/400. Regardless, it is this phenomenon
> that allows the Moon to perfectly cover the Sun during an
> eclipse allowing us to view the corona.
Carol: Yes, a total eclipse, but not an annular one.
As Isaac Asimov said of
> If the Moon were a different size or had a different orbitQuote
There is no astronomical reason why the moon and
> the sun should fit so well. It is the sheerest of coincidences,
> and only the Earth among all the planets is blessed in this
> life would not exist on Earth as we know it. And life would
> also have been much different if it were not as reflective as
> it is.
Carol: The moon’s albedo is only about 7% - it’s not really very reflective at all.
The Moon is in the exact spot it is required to be, no
> other place it could be, for Earth to be what it is. The Moon
> is also the only orbiting body in the solar system with a
> stationary ( one side perpetually facing its host) and
> near-perfect circular orbit.
Carol: No, not true. Most moons are in synchronous orbit around their parent planet. The exceptions are the irregular outer moons of the giant planets. And the moon's orbit is elliptical, not near-perfectly circular.
> According to astrophysicist Bernard Foing:
> Kind of like what was on Earth for the 3 billion yrs prior toQuote
...the Earth’s moon has helped stabilize our planet so
> that its axis of rotation stays in the same direction. For this
> reason, we had much less climatic change than if the Earth had
> been alone. And this has changed the way life evolved on Earth,
> allowing for the emergence of more complex multi-cellular
> organisms compared to a planet where drastic climatic change
> would allow only small, robust organisms to survive.
> the Pre-Cambrian expolosion 600,000,000yrs ago .
Carol: The origins of life on earth aren’t dependent only on the moon. Conditions on earth itself have to be taken into account.
> > Why has the earth got ‘no business’ having such a moon?
> It ain't got no business having one because no other rocky
> planet has a moon (Mar's "moons" for example are captured
> asteroids) let alone the 5th largest moon in the solar system
> and proportionally by far the largest compared to its host.
Carol: Which law of the universe is earth breaking by being alone among the rocky planets in having such a moon?
> The theoretical model that suggests the Moon was created by an
> impact, two impacts no less, by some unknown body is so complex
> as to be only valid in a computer model requiring a near
> impossible perfect storm of events.
Carol: It’s complex, but not impossible, and although it leaves some questions unanswered, it’s a lot more plausible than ‘aliens did it’. Some supporting evidence:
The giant impact hypothesis is the currently-favoured scientific hypothesis for the formation of the Moon. Supporting evidence includes: the identical direction of the Earth's spin and the Moon's orbit, Moon samples that indicate the surface of the Moon was once molten, the Moon's relatively small iron core, lower density compared to the Earth, evidence of similar collisions in other star systems (that result in debris disks), and that giant collisions are consistent with the leading theories of the formation of the solar system. Finally, the stable isotope ratios of lunar and terrestrial rock are identical, implying a common origin.
As Isaac Asimov also said:
It’s too big [the Moon] to have been captured by the
> Earth. The chances of such a capture having been effected and
> the moon then having taken up nearly circular orbit around our
> Earth are too small to make such an eventuality
Carol: But you're suggesting that the aliens set it up for capture. How did they push it there then, slow it down and make sure earth captured it and held it in its present orbit? Its sheer size would make this difficult, if not impossible, according to what you’ve just quoted above.