Crosswords1 min ago
Artificial Moon?
19 Answers
Hi folks,
I'm not sure if this controversial topic has been discussed before but as I've missed the possible debate about it, I would like to hear your thoughts today.
I have always held the moon in high regard (no pun intended) ever since I was a boy. It fascinated me more than almost anything else in nature as I was growing up. Now an adult and still curious about our nearest celestial body, it is clear to me that this object has more questions than answers. Never discussed by the mainstream media as anything other than a fortunate oddity which without it's presence Earth would have developed in a very different way and possibly never developed a stable enough climate to allow complex life to flourish.
Citing a couple of examples for you now about the mysteries of the moon may help this debate start;
1) It's position from Earth - It is placed exactly so it eclipses the Sun's disc, holds the Earth in a stable spin (maintains it's angular wobble,) and allows persistent but gentle tides to ebb and flow across the coastlines.
2) It's geological resonance- Nasa astronauts placed seismometers on the Moons surface after one Moon landing to record seismic activity. They then deliberately impacted small and large objects such as discarded rocket parts onto the surface of the Moon and Nasa recorded the shock waves in the Moon which "rang like a bell" for up to 30mins for the smaller impactors and 3 hours for the larger ones, something not seen here on Earth.
3) Current accept Moon creation theory has large holes - The impactor theory is the widely accepted one where a Mars size body in the same orbit as Earth collided with our young planet and the resulting debris coalesced and formed the Moon. This though doesn't explain the mystery of the composition of Moon rocks brought back to Earth for examination which shows high concentrations of titanium (3 times more than mines on Earth) and other materials thought to be older than our Solar System.
This is a highly controversial topic and theories online are as wild as a 'Moon spaceship' brought to our Solar system and placed Earth orbit by an alien race for global and specie's control...
I will accept that there is something very odd about our Moon but I'd like to here AB's points of view. I look forward to reading your replies :)
IHI
I'm not sure if this controversial topic has been discussed before but as I've missed the possible debate about it, I would like to hear your thoughts today.
I have always held the moon in high regard (no pun intended) ever since I was a boy. It fascinated me more than almost anything else in nature as I was growing up. Now an adult and still curious about our nearest celestial body, it is clear to me that this object has more questions than answers. Never discussed by the mainstream media as anything other than a fortunate oddity which without it's presence Earth would have developed in a very different way and possibly never developed a stable enough climate to allow complex life to flourish.
Citing a couple of examples for you now about the mysteries of the moon may help this debate start;
1) It's position from Earth - It is placed exactly so it eclipses the Sun's disc, holds the Earth in a stable spin (maintains it's angular wobble,) and allows persistent but gentle tides to ebb and flow across the coastlines.
2) It's geological resonance- Nasa astronauts placed seismometers on the Moons surface after one Moon landing to record seismic activity. They then deliberately impacted small and large objects such as discarded rocket parts onto the surface of the Moon and Nasa recorded the shock waves in the Moon which "rang like a bell" for up to 30mins for the smaller impactors and 3 hours for the larger ones, something not seen here on Earth.
3) Current accept Moon creation theory has large holes - The impactor theory is the widely accepted one where a Mars size body in the same orbit as Earth collided with our young planet and the resulting debris coalesced and formed the Moon. This though doesn't explain the mystery of the composition of Moon rocks brought back to Earth for examination which shows high concentrations of titanium (3 times more than mines on Earth) and other materials thought to be older than our Solar System.
This is a highly controversial topic and theories online are as wild as a 'Moon spaceship' brought to our Solar system and placed Earth orbit by an alien race for global and specie's control...
I will accept that there is something very odd about our Moon but I'd like to here AB's points of view. I look forward to reading your replies :)
IHI
Answers
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No other moon in our solar system eclipses the sun precisely. Some partially eclipse and some over eclipse but the Earth's moon matches the size of the Sun exactly, hence we can see the Sun's corona. It is also unlike any other moon in our system because of it's size compared to it's planet. It's enormous, bigger than Pluto, and is unmatched in it's ratio of size for moon to planet.
I have no expert knowledge to answer your questions or even know if the claims are correct or urban myth but my toughs are as follows:
Of course Earth would have developed differently without the moon. I suspect it is only where such a stabilising influence has been formed (dual planet really) that intelligent life as we can evolve to marvel at it.
It's position is merely fortunate. Luckily for us we are around when it is more or less the right distance for the blocking of the sun during a total eclipse. Quite a sight. But the moon is gradually working it's way out so at some point it would be like that.
I suspect here are reasons for the result you give re resonance. Not qualified to comment. Or even know if it is that unusual.
If two bodies collided I don't see that the resulting different sized orbiting bodies necessarily has to be exactly the same. Seems quite reasonable that he 2 bodies were different to start with, and maybe certain elements have a better tendency to fly out than others. Not qualified to say but I'm not overly surprised.
I think we can take it as true that wilder theories are for pub conversations and not to be taken too seriously.
Of course Earth would have developed differently without the moon. I suspect it is only where such a stabilising influence has been formed (dual planet really) that intelligent life as we can evolve to marvel at it.
It's position is merely fortunate. Luckily for us we are around when it is more or less the right distance for the blocking of the sun during a total eclipse. Quite a sight. But the moon is gradually working it's way out so at some point it would be like that.
I suspect here are reasons for the result you give re resonance. Not qualified to comment. Or even know if it is that unusual.
If two bodies collided I don't see that the resulting different sized orbiting bodies necessarily has to be exactly the same. Seems quite reasonable that he 2 bodies were different to start with, and maybe certain elements have a better tendency to fly out than others. Not qualified to say but I'm not overly surprised.
I think we can take it as true that wilder theories are for pub conversations and not to be taken too seriously.
It eclipses the sun precisely only at present (because it is 400 times closer to the Earth than the Sun is but has a diameter of one four hundreth of the Sun).
It is slowly moving away from the Earth at at some time in the future will not be apparently large enough to obscure the Sun.
Also in the future the Earth and the Moon will become double "tidally locked" (the moon is already tidally locked to the earth in that its period of rotation on its axis is the same as the period of its orbit around the Earth). Eventually the Earth's period of rotation on its axis will become identical to the moon's period of orbit and then the tides in the oceans will be no more.
All this assumes that the Sun will not die and swell into a red giant beforehand thus swallowing up the Earth and the moon (and probably Mars and Jupiter as well).
It is slowly moving away from the Earth at at some time in the future will not be apparently large enough to obscure the Sun.
Also in the future the Earth and the Moon will become double "tidally locked" (the moon is already tidally locked to the earth in that its period of rotation on its axis is the same as the period of its orbit around the Earth). Eventually the Earth's period of rotation on its axis will become identical to the moon's period of orbit and then the tides in the oceans will be no more.
All this assumes that the Sun will not die and swell into a red giant beforehand thus swallowing up the Earth and the moon (and probably Mars and Jupiter as well).
even now it does not always eclipse the Sun both it's orbit and our own around the sun are not circular and thus an annular eclipse can occur:
http://
http://
As others have mentioned a lot of this, particularly the distance/ eclipse thing, is only true now. Some time ago, it was not the case and the Moon was closer; in the far future it will be further away. Now (plus or minus quite a long time, admittedly) is just a lucky time to be looking at the system. Rather like watching, say, two cars' indicator lights blinking until they come into sync with each other for one blink and thinking "Wow! How amazing is that?!" for the precise second where things line up just right. And then it diverges again and it's not so amazing any more.
The Sun always illuminates half the moon's surface, mibn. The "phases" that we see from the Earth depend on the angle between the Earth, the Moon and the Sun during the 28 day lunar cycle. In fact a full moon occurs when the three are in alignmen, with the Earth in the middle. This explains:
http://
A lunar eclipse can only occur on the night of a full moon and, unlike a Solar eclipse, is visible from anywhere on the "night" side of the Earth. This explains:
https:/
http://
A lunar eclipse can only occur on the night of a full moon and, unlike a Solar eclipse, is visible from anywhere on the "night" side of the Earth. This explains:
https:/
The waxing and waning thing tends to get me too. Although I can understand the Earth's shadow could miss a full moon when not exactly aligned. I figured it was probably due to the angle of elevation at which we see the moon but that simply puzzled me as to how one can see crescents and new moons when they would happen at day when it's too bright. I've come to the conclusion I must be imagining those.
Thanks Tora.
With perfect alignments, where the Moon passes directly through the centre of Earth's shadow, the Full Moon virtually disappears. This one will be fairly close - https:/
The Total Lunar Eclipse of 28 September should be quite orangey . . . weather permitting - https:/
With perfect alignments, where the Moon passes directly through the centre of Earth's shadow, the Full Moon virtually disappears. This one will be fairly close - https:/
The Total Lunar Eclipse of 28 September should be quite orangey . . . weather permitting - https:/
@I_Hate_Infinity
I'm late to the thread and (1) has already been covered, the short version of which is that the moon's orbit around us is elliptical *and* the earth's orbit around the sun is elliptical so, if earth is closer to the sun and the moon is at its furthest from us, the eclipse will be of the 'annular' type.
Even then, the alignments have to be just right: the moon's orbit is tilted, relative to earth's path around the sun, making partial eclipses more common and, when it is a partial, there is no way for the layperson to assess that it might have been annular, or full, or "over-full", from a more advantageous viewpoint (which would have to be off-planet).
(2) The thing which makes a bell, a vibrating string or other resonating object decay to nothing, on earth is the air around it. In conducting sound waves away, it removes vibrational energy. Earthquake vibrations can be detected thousands of miles away but, ultimately, are absorbed by what they travel through. Mantle rock is supposed to be soft and gooey; ideal for sound absorption. The oceans could absorb some too.
The moon, by contrast has no molten core, no 'gooey' mantle; it is solid right the way through. There is no ocean or atmosphere to transmit sound and the vacuum of space will not conduct vibrational energy away, either. This is the conventional explanation of why it rings like a bell, when impacted. You've undoubtedly read this and, whilst it's none of my business, I'm curious about why you find this explanation inadequate?
I haven't fully addressed the issue of lunar surface dust, which, in jiggling around, should dissipate vibrational energy, almost like a liquid. The tests showed ringing did decay, eventually, so some internal dissipation is going on.
(3) No mining has been done on the moon, so we've only sampled the surface. For starters, the remnant of the "Thea" impactor may have completely liquified. Heavier elements, like iron would have sunk, to form a core. Titanium has a lower density and would have floated to the upper layers - a sort of 'fractionation' occurs, in much the same way that inner planets are more rock than gas and outer planets are more gas than rock.
You would also expect the last of the debris, from the Thea impact, to fall back to the moon's surface to be the less dense material. The moon became techtonically inert, whilst the earth has subduction zones; for every mil that the Atlantic is wide, a similar amount of Pacific ocean floor has been shoved into the depths. The earth's surface has been churned up so surface minerals are a varied mix.
Additionally, an impact on the moon would send rock debris and dust and huge distances because of the lower gravity and the complete absence of air resistance. A succession of impacts would mean that materials would spread over the surface giving a very uniform blend, such that multiple sampling sites, of the various moon missions all get similar mineral mixtures.
Carl Sagan's Cosmos series featured the account of a 12th/13th century monk who observed a bright flash at the edge of the moon, followed by a bright plume, becoming a detached crescent, then a fogging of the surface, lasting some hours. A convincing description of an impact.
Oddly, I have not seen this story mentioned again in the 30-odd years since that series was first broadcast. It may have been discredited by referencing astronomical archives from other parts of the world for the claimed date, which were not available when the series was made.
I'm late to the thread and (1) has already been covered, the short version of which is that the moon's orbit around us is elliptical *and* the earth's orbit around the sun is elliptical so, if earth is closer to the sun and the moon is at its furthest from us, the eclipse will be of the 'annular' type.
Even then, the alignments have to be just right: the moon's orbit is tilted, relative to earth's path around the sun, making partial eclipses more common and, when it is a partial, there is no way for the layperson to assess that it might have been annular, or full, or "over-full", from a more advantageous viewpoint (which would have to be off-planet).
(2) The thing which makes a bell, a vibrating string or other resonating object decay to nothing, on earth is the air around it. In conducting sound waves away, it removes vibrational energy. Earthquake vibrations can be detected thousands of miles away but, ultimately, are absorbed by what they travel through. Mantle rock is supposed to be soft and gooey; ideal for sound absorption. The oceans could absorb some too.
The moon, by contrast has no molten core, no 'gooey' mantle; it is solid right the way through. There is no ocean or atmosphere to transmit sound and the vacuum of space will not conduct vibrational energy away, either. This is the conventional explanation of why it rings like a bell, when impacted. You've undoubtedly read this and, whilst it's none of my business, I'm curious about why you find this explanation inadequate?
I haven't fully addressed the issue of lunar surface dust, which, in jiggling around, should dissipate vibrational energy, almost like a liquid. The tests showed ringing did decay, eventually, so some internal dissipation is going on.
(3) No mining has been done on the moon, so we've only sampled the surface. For starters, the remnant of the "Thea" impactor may have completely liquified. Heavier elements, like iron would have sunk, to form a core. Titanium has a lower density and would have floated to the upper layers - a sort of 'fractionation' occurs, in much the same way that inner planets are more rock than gas and outer planets are more gas than rock.
You would also expect the last of the debris, from the Thea impact, to fall back to the moon's surface to be the less dense material. The moon became techtonically inert, whilst the earth has subduction zones; for every mil that the Atlantic is wide, a similar amount of Pacific ocean floor has been shoved into the depths. The earth's surface has been churned up so surface minerals are a varied mix.
Additionally, an impact on the moon would send rock debris and dust and huge distances because of the lower gravity and the complete absence of air resistance. A succession of impacts would mean that materials would spread over the surface giving a very uniform blend, such that multiple sampling sites, of the various moon missions all get similar mineral mixtures.
Carl Sagan's Cosmos series featured the account of a 12th/13th century monk who observed a bright flash at the edge of the moon, followed by a bright plume, becoming a detached crescent, then a fogging of the surface, lasting some hours. A convincing description of an impact.
Oddly, I have not seen this story mentioned again in the 30-odd years since that series was first broadcast. It may have been discredited by referencing astronomical archives from other parts of the world for the claimed date, which were not available when the series was made.
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