The Moon

[blazincajun]

At what position does the Moon orbit the Earth? What I mean is does the Moon orbit at the equater or north or south poles? <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

Relative to the equator, the moon's orbit varies between 18 and 29 degrees in a 18.61 year cycle.<br /><br />Relative to the orbital plane of the earth, it's 5.1 degrees.<br /><br />MW<br /><br />(From the RASC Observer's Handbook) <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[blazincajun]

thanks <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

By the way, the moon is currently very near the maximum inclination.<br />This led to very low full moons during the summer <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[3488]

And very high full moons during the Winter!!<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[MeteorWayne]

That is correct, sir.<br />It should be brilliant outside on a snow covered full moon night! <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[slimnek3]

is the moon visible everyday? or are there some days it doesn't show itself?

 

[doubletruncation]

The moon is always "there" so to speak, however the fraction of the moon that we see illuminated depends on the earth-moon-sun angle. Once a "moonth" when the moon is on the sun-side of the earth the side facing us is not illuminated so you wouldn't see it (this is a new moon), about 2 weeks later the moon will be on the opposite side of the earth and the entire side facing us is illuminated (this is a full moon). There is a pretty good demonstration of this here:<br />http://www.schoolsobservatory.org.uk/astro/textb/solsys/moonphs.htm <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

The phases of moon is part of civilisation.Moon yides is a great practical thing,sort of controls happenig on earth,not in astrological sense.

 

[nexium]

The moon does have control of some earthly things such as tides, but I would omit the word "great".<br />I agree the moon is always there, but is difficult to see for a day or two (each month) while the side facing Earth has no sunlight.<br />Also, each day the moon is below the horizon (from any specific location) approximately 12 hours per day. Neil

 

[3488]

Hi there, it is worth noting that at the high latitudes, the moon will stay up for the full 24 hours, in Winter in the high arctic, you have the midday Full Moon, the lunar counterpart to the Midnight Sun in Summer.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[nexium]

Does anyone agree with Andrew? I seems more likely that the moon would not rise at all, at high lattitudes during December and early January near the North pole. I can however imagine 24 hours of moonshine around June 21. Neil

 

[willpittenger]

Would you believe me if I told you this?<br /><br /><font color="yellow">If the 12th of that month was a full moon, on the 3rd Tuesday of that month, the moon would vanish.</font><br /><br />If you said yes, I would like to sell you the Pekin Bridge (in Pekin, IL), the Shade-Loman bridge, the Cedar Street Bridge, the Robert Micheals Bridge, the Murray Baker Bridge, and the McCluggage Bridge. All are link downtown Peoria, IL with its suburbs or the suburbs with each other. All cross the vitally important Illinois River. If you control all six of these bridges, you will force all commuters in the area to pay your tolls. Each bridge is only $100,000,000.<br /><br />But wait, if you act now and buy all six bridges, I will throw in the smaller and older Franklin Street Bridge at no cost to you. That's a $1,000,000 value -- absolutely free. Back when Peoria had a vaudeville act market, they came up with the phrase "But will it play in Peoria?" If you buy all seven bridges, you will be assured of playing here. <br /><br /><br /><br />All joking aside, the only real way for the moon not to be visible on some days would be if you are near a pole. I think one of the others mentioned that. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[rfoshaug]

<blockquote><font class="small">In reply to:</font><hr /><p>Does anyone agree with Andrew? I seems more likely that the moon would not rise at all, at high lattitudes during December and early January near the North pole. I can however imagine 24 hours of moonshine around June 21. Neil<p><hr /></p></p></blockquote><br /><br /><br /><br />Andrew is correct. I live at 69° North, and this is how it looks from here:<br /><br />Each month there is a period when the moon is constantly above the horizon for several days. Then it gets lower in the sky, and there's a period when it rises and sets each day. Then there's a period when it is below the horizon and cannot be seen for several days until it starts going higher each night until it is constantly above the horizon again. This entire cycle takes about a month.<br /><br />The lunar phase at which these events occur vary with the season. This has a reason: At full moon, the sun and moon are in exact opposite parts of the sky (that's why we get to see the fully illuminated side of the moon). So at full moon, the moon is where (relative to the background stars) the sun will be in exactly 6 months, while at dark moon the moon is where the sun is at that time.<br /><br /><br />This means that at full moon in winter, the moon is going as high in the sky as the sun is in the summer, and at 69ºN this means that the full moons around christmas never sets. In the early summer, however (end of June), the full moon cannot be seen as it is constantly below the horizon just like the sun will be 6 months later.<br /><br />This is how the moon behaves as seen from north of the arctic circle ("normal" means it both sets and rises every day):<br /><br /><pre><br />Date | Dark moon | Waxing | Full moon | Waning<br />-------------|-------------|-------------|-------------|-------------<br />March 21 | Normal | Never sets | Normal | Never rises<br />June 21 | Never sets | Normal | Never rises | Normal<br />September 21 | Normal</pre> <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[zarnic]

I know there's a lot of interest in higher-order stellar objects but I have two questions about the moon, both are basic astronmy and if I was facing an instructor I would probably see a frown, at any rate here it goes ...<br />first, what causes the drastic color changes we see from afar, and second, if the moon as such low gravity where does the debri go from impacts? See, basic stuff! <div class="Discussion_UserSignature"> <p><em>Wisdom doesn't automatically come with old age. Nothing does - except wrinkles.</em> A. Van Buren, 1978<br />* <em>An unbreakable toy is useful for breaking other toys.</em>  -- according to Van Roy</p> </div>

 

[MeteorWayne]

Any color changes we see of the moon are caused by the earth's atmosphere. The color of the moon is space is just that of sunlight reflecting off the surface, so doesn't change.<br /><br />On the other hand, our atmosphere has varying amounts of moisture and dust, and the moonlight passes through different amounts of air.<br /><br />When the moon is overhead it passes through the least amount of the atmosphere (60 or 70 miles worth), whereas close to the horizon it is passing through hundreds of miles of atmosphere, which tends to redden it. Dust refracts different colors of light differently than pure air, and than moisture. So the amount of each causes different modifications to the color we perceive.<br /><br />While the moons gravity is lower than the earth's it is more than enough to keep almost anything blasted off the surface. If you look at the crater Copernicus, you can see long "rays" where material that was blasted out from the crater fell back to the surface.<br /><br />For a very energetic impact, a tiny percentage of the material may be accelerated to greater than the moon's escape velocity and goes into orbit around the earth or the sun. Some of the meteorites we have discovered here on earth came from the moon. Not many, but some.<br /><br />Great questions!!<br /><br />Welcome to Space.dom!!!<br /><br />BTW, I'm not frowning at your questions, I'm smiling, and am happy to answer them. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[origin]

What drastic color changes are you refering to?<br /><br />As far as impacts on the moon if the ejected material exceeds the escape velocity of the moon it will not fall back on the moon and may end up on earth or out in space. If the ejected material is traveling < escape velocity it will end up back on the moon - possibly on the opposite side of them moon.<br /><br /> edited to add - 1 minute too slow. <br /> <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

I think he's referring to how red the moon can appear on a humid night near the horizon. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[zarnic]

I can see I didn't make myself clear. The color change refers to the 'man in the moon'-image we heard about as kids, dark in one place and light in another, not color changes caused by our atmosphere. In fact, if impact debri didn't reach escape velocity I would think we would see less and less of a change. <div class="Discussion_UserSignature"> <p><em>Wisdom doesn't automatically come with old age. Nothing does - except wrinkles.</em> A. Van Buren, 1978<br />* <em>An unbreakable toy is useful for breaking other toys.</em>  -- according to Van Roy</p> </div>

 

[MeteorWayne]

I guess you disn't make yourself clear. Sorry my assumption was wrong.<br />You said color change, what you meant was the different reflectivity (brightness) of the surfaces. The color is pretty much the same, although if you look with devices that look at detailed structure of the reflected light, there are color differences. These are too subtle to be detected by the human eye though.<br />BTW, it's debris, not debri <img src="/images/icons/smile.gif" /><br /><br />The different brightness of parts the lunar surface is caused by the different composition of the materials.<br /><br />All of it is very dark (like a freshly laid asphalt surface), but the maria (large dark areas) are where magma came form below the surface and flooded large areas. The bright rays are fresher and different materials.<br />Some of the brightness difference is caused by the size of the particles as well.<br /><br />It's a very complex answer.<br /><br />Wayne <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[adrenalynn]

If I understand what you're asking - <br /><br />Remember that the moon has massive craters and more massive mountains, with the highest peak being taller than most of the tallest mountains on earth - over 18,000 ft.<br /><br />As light appears to move across the surface, you see long shadows and pools of light. In a telescope, you can distinguish the nature. To the naked eye, however, the features on the moon appear to change.<br /><br />Is this what you're referring to?<br /><br /><br />There is also Earthshine. This is an effect where the sunlight reflecting off of the earth can be seen to illuminate a sliver of the moon's dark side. Best seen when the moon is a faint, thin cresent. <br /> <br />[edit] Also echoing MeteorWayne's "Welcome!" <div class="Discussion_UserSignature"> <p>.</p><p><font size="3">bipartisan</font>  (<span style="color:blue" class="pointer"><span class="pron"><font face="Lucida Sans Unicode" size="2">bī-pär'tĭ-zən, -sən</font></span></span>) [Adj.]  Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.</p><p><strong><font color="#ff0000"><font color="#ff0000">IMPE</font><font color="#c0c0c0">ACH</font> <font color="#0000ff"><font color="#c0c0c0">O</font>BAMA</font>!</font></strong></p> </div>

 

[adrenalynn]

Seems like we might all deconstruct the moon here and lay it out bit-by-bit before we're done. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p>.</p><p><font size="3">bipartisan</font>  (<span style="color:blue" class="pointer"><span class="pron"><font face="Lucida Sans Unicode" size="2">bī-pär'tĭ-zən, -sən</font></span></span>) [Adj.]  Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.</p><p><strong><font color="#ff0000"><font color="#ff0000">IMPE</font><font color="#c0c0c0">ACH</font> <font color="#0000ff"><font color="#c0c0c0">O</font>BAMA</font>!</font></strong></p> </div>

 

[zarnic]

Ok, NOW I understand, always helps to say what one means. Oh, and TY for the welcomes ... I come here often but seldom know what to ask that doesn't sound too stupid. I saw a close-up of the moon today and that generated the questions. Glad there is somewhere to go where there is someone to ask. <div class="Discussion_UserSignature"> <p><em>Wisdom doesn't automatically come with old age. Nothing does - except wrinkles.</em> A. Van Buren, 1978<br />* <em>An unbreakable toy is useful for breaking other toys.</em>  -- according to Van Roy</p> </div>

 

[MeteorWayne]

"And much of the impact debris from the lunar bombardment DID reach the Earth"<br /><br />Don't think that's true eddie.<br /><br />A very small amount did, as a few meteorites reflect that, but to say "much" is way too much.<br /><br />Most of the debris wound up back of the surface of the moon, and very small amount wound up beyond the moon's gravity well, and a very small part of that material wound up on earth.<br /><br />AFAIK, there's only a dozen or two lunar meteorites that have been discovered.<br /><br />MW <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[3488]

Hi zarnic.<br /><br />Welcome to SDC!!<br /><br />MeteorWayne is correct. True, the Moon's gravity is weaker than Earth's, but it is still<br />quite strong. Surface gravity is approx 16.67% of Earth's, so it is not insignificant by <br />any means. It would thake a gigantic impact to liberate huge amounts of lunar material from the<br />moon. <br /><br />MeteorWayne is correct. The vast majority of impact debris (99.99% of it at least), falls back.<br /><br />Our Moon is the sixth largest, but second densest in the solar system (just pipped by <br />Jupiter's Io).<br /><br />A few facts:<br /><br />Average orbital distance from Earth: 384,500 KM.<br /><br />Diameter of Moon: 3,476 KM.<br />Density: 3.34 G/CM3.<br />Surface Gravity: 1.62 metres per second squared.<br />Escape Velocity 2.38 KMS or 1.47 MPS or 8,561 KPH / 5,321 MPH.<br /><br />Max Daytime Temperature on Equator: 117 Celsius.<br />Min Predawn Temperature on Equator: Minus 167 Celsius.<br />Min Polar Temperature in permanent shadow: Minus 230 Celsius.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>