Seeing the moon during the day - Question

sbsquarepants

Firstly, my apologies if this is a ridiculous question!
Sometimes, as we all know, it's possible to see the moon well into the day time. Does this mean that at that same time, on the exact opposite point of the globe, it is night time but the moon is not visible? That just doesn't sound right to me, I have never heard of a place where the moon can't be seen, barring clouds, looking in the wrong direction, blindness etc!
My original take was that they (on the opposite side) must be able to see the segment of the moon that we can't, but then what happens in the case of full moons.
I know there must be a simple explaination for this but i just can't see it!This does have me a litlle bit intrigued and i would geniunely like an answer if anyone knows it.

PeakOutput

im guessing now but i imagine its because

when you see the moon during the day its either early in the morning or late in the evening so its at the end or the start of night time

so as the earth rotates we are put into light but still at the right angle to see the moon for a little while longer, its not the opposite side of the world thats in dark at this time its the places that are a 4/5/6hundred miles away and just havnt been hit with morning yet or are already in darkness at the start of the night

in my head that makes sense but im not sure it does in text

norrie rugger

sbsquarepants wrote: »

Firstly, my apologies if this is a ridiculous question!
Sometimes, as we all know, it's possible to see the moon well into the day time. Does this mean that at that same time, on the exact opposite point of the globe, it is night time but the moon is not visible? That just doesn't sound right to me, I have never heard of a place where the moon can't be seen, barring clouds, looking in the wrong direction, blindness etc!
My original take was that they (on the opposite side) must be able to see the segment of the moon that we can't, but then what happens in the case of full moons.
I know there must be a simple explaination for this but i just can't see it!This does have me a litlle bit intrigued and i would geniunely like an answer if anyone knows it.

How do you know that you are not seeing the Sun, during the night?

sbsquarepants

But you gain or loose 1 hour for every 15 degrees you travel depending on if you go west or east, so at the exact opposite spot on the globe (180 degrees) it is 12 hours difference, ie the middle of the day here is the middle of the night there. No?
I think the answer must have something to do with the moons position relative to where you view it from in the north or south direction, but that's little more than a guess. Sorry if that sounds confusing, i always get longitude and latitude mixed up, so i thought i'd better stick to north, south, east and west!

sbsquarepants

norrie rugger wrote: »

How do you know that you are not seeing the Sun, during the night?

Eh, i dont! Besides i see in the conpiracy theories forum today that there are 2 suns now, apparently they hide the second one from us using airplanes for reasons that didn't quite make sense. So who knows:)

backboiler

Not the most ridiculous question but on the way there. :-)

1. The moon rises and sets just like the sun so yes, there are places on earth now that can't see the moon just now but it will rise there in a few hours.

2. The moon is lit by the sun and the "shape" of the moon as we see it depends on the angle between the earth, moon and sun. For everyone on earth who can see the moon over the course of a day or so the moon looks lit up much the same.

ISAW

backboiler wrote: »

Not the most ridiculous question but on the way there. :-)

1. The moon rises and sets just like the sun so yes, there are places on earth now that can't see the moon just now but it will rise there in a few hours.

2. The moon is lit by the sun and the "shape" of the moon as we see it depends on the angle between the earth, moon and sun. For everyone on earth who can see the moon over the course of a day or so the moon looks lit up much the same.

when the Moon is "full" it is opposite the Sun in the Sky. This may happen at any time of the day or night but a day either side of it looks fairly much the same and you cant say just by sight when the exact "full moon" is.

The Moon and the sun are both about half a degfree in angular measurement (30 seconds of arc). Now we know the Earth rotates and goes round the sun but for astronomers you can think of things like ancient times and assume the Earth doesn' t move and the sun rises and sets every day and the stars go round the Earth. If you could stop the Earth moving and see eight through it and under your feet and look directly art the Sun at any time (not advised) and still see the stars (yes they are there during the day the Mid winter daytime stars are he same as the midsummer nighttime ones. Just think about it. If you are on one side of the sun the night side of the earth looks "out" into stars which when you go around to the other side of the sun are "behind the Sun " during the day and vice versa.

Anyway If the Earth didn't spin you would see the Sun trace a 360 degree path right round the background Stars in a year - al ilittle more than a degree a day. the Moon however goes round the whole sky in a lunar month - about four weeks. dont forget the earth has also travelled about a twelfth of the way round the Sun (or from our point of view the Sun moves about 30 degrees round every month when the Moon moves 360).

So the sun does about a degree a day but the Moon a degree every two hours. By the Way it is retrograde. If you could stop the Earth and stars the Sun would move not East to West but west to east in relation to the background stars.

Now back to your question. Assuming no clouds can you see the Moon before it rises?
No you can't! therefore you can't see it at all times! Likewise someone on the far side of Earth. When the Moon is at its highest the people on the fat side wont see it till it rises there about six hours later.

By the way the moons plane is similar to the Sun going round the earth (yes I know the it is the Earth axis and the Earth goes round the sun but we are talking as seen from Earth) so that implies somewhere On Earth there could be an all day Moon and "no Moon 24 hour day". There are cloudless days we don't see the Moon as well because the New moon is near the Sun in the sky. if the Moon is traveling over ten times faster it will catch up with the sun and overtake it.

Depending on how you measure fixed star to fixed star , phase to phase etc.

http://en.wikipedia.org/wiki/Month

there are different months.

The Moon also presents the same facre to us on earth (bar a slight wobble back and forth).

Take a jam jar and face the label to the center of the table and rotate the jar in an orbit around the center. Notice to keep the Label facing center you will rotate the jar once every full orbit? the Moon behaves the same rotating once every time it goes round earth . Of cource Earth rotates about 29 times in that period so the people on earth (both sides) get to see the Moon for half of every day (except when it is near the sun in the sky).

Hope that helps.

lord lucan

Off topic but it's a beautiful clear freezing night out and the moon looks gorgeous in the cloudless sky.:)

sbsquarepants

Thanks for the help folks, i appreciate it. I still have a bit of a block here though. Firstly let me state, i'm not actually as stupid as this question suggests! Of course i know the moon "rises and sets" so to speak and it may not be visible now from wherever, but will be later on. But my question only applies to when it is fully visible, i still have trouble picturing how it can be visible from the exact opposite point on the globe, only those 2 exact points at that exact time. For it to be day time for us we must be facing the sun, the exact opposite must be true for the exact opposite point on the globe, therefore we must be facing in opposite directions, how can we both see the exact same thing? I know i must be just missing that eureka moment where it will all suddenly make it make sense to me, but i have to admit i'm scratching my head here trying to get there!

And yes the moon did look gorgeous last night:D

NoQuarter

sbsquarepants wrote: »

But my question only applies to when it is fully visible, i still have trouble picturing how it can be visible from the exact opposite point on the globe, only those 2 exact points at that exact time.

It Cant! Read ISAW's post again! If there is a full moon here, the same full moon cannot be seen in australia etc at the exact same time! You cannot see through the earth! So your not that stupid after all!

ISAW

sbsquarepants wrote: »

But my question only applies to when it is fully visible, i still have trouble picturing how it can be visible from the exact opposite point on the globe, only those 2 exact points at that exact time.

You wont see a full Moon like this till about 12 hours later. the only way two "opposite" people will see the same moon is when it is near the East/west horizon and one will see it setting when the other sees it rising. it will be a half- moon to both of them but upsoide down to one.

By the way the moon is upside down in the Southern Himishpere as re the constellations near the equator. Upside down when compared to us that is.

For it to be day time for us we must be facing the sun, the exact opposite must be true for the exact opposite point on the globe,

NO!
the Earth must be facing the Sun! An observer can face away from the sun such as towards the horizon at midday to look at a half-Moon.

therefore we must be facing in opposite directions, how can we both see the exact same thing?

someone at midnight looking straight up and someone on the other side of Earth at Midday looking straight up ARE looking in opposite direction. The person looking up at mid day however won't see much because the Sun drowns out the background stars. If they both look straight up for 24 hours eventually they will change places and see what the other saw.

No you are not stupid. I think you have what educationalists call a "niave" view/. If you ask children to draw the Earth they draw circle. then ask them to put a house on it and one in australia and to show it rain in both places. "Down" quickly becomes the bottom of the drawing instead of "towards the center of the Earth" .
Maybe your problem is a consequence of mixing local and celestial reference frames?

I know i must be just missing that eureka moment where it will all suddenly make it make sense to me, but i have to admit i'm scratching my head here trying to get there!

And yes the moon did look gorgeous last night:D

Don't worry the cognitive conflict will hopefully resolve itself when you consider what do you mean by "looking in the same direction" from the point of view of a local on the Planet and a person out in space looking at the Earth-sun-Moon system.

sbsquarepants

ISAW wrote: »

You wont see a full Moon like this till about 12 hours later. the only way two "opposite" people will see the same moon is when it is near the East/west horizon and one will see it setting when the other sees it rising. it will be a half- moon to both of them but upsoide down to one

An observer can face away from the sun such as towards the horizon at midday to look at a half-Moon.


.

But what about a full moon? And not one that can be seen 12 hours later, how can it be seen simultanously? Or can it, am i infact imagining that i've seen full moons in the day time when i've actually only seen half moons?

Ps - Thanks for your patience:)

ISAW

sbsquarepants wrote: »

But what about a full moon? And not one that can be seen 12 hours later, how can it be seen simultanously? Or can it, am i infact imagining that i've seen full moons in the day time when i've actually only seen half moons?

Ps - Thanks for your patience:)

the Full Moon is when the Earth is EXACTLY between the Sun and the Moon. Same as an eclipse except the Moon doesn't go into the Earths shadow ( as it does during an Eclipse) So the Moon is a bit above or below a line drawn between the center of the Sun and Earth.

so the Only person seeing an EXACT full Moon Would have to look at the Moon at Exactly this time. As I stated a waxing or waning gibbous Moon looks much the same as a full Moon so between about a day before and day after it looks Much the Same.
You CANT see a full moon at midday because it is on the far side of the Earth but you can Seen a full Moon on the opposite horizon just as the Sun is setting or Rising so you could see it in daylight - well twilight. given the waning gibbous Moon which was exactly full at your local Sunset it could move say about six degrees in twelve hours and the sun only move half a degree. This would mean at sunrise the Moon would have moved about 5 and a half degrees closer to the Sun (about the distance between the "pointers" in the plough) and so you would see a "full Moon" setting just before Sunrise.

sbsquarepants

ISAW, you've the patience of a saint!
I think i actually get it now. I'm still gonna keep a sneaky eye out for a mid day full moon though, you know, just to be sure to be sure! If i spot one i'll let you know, ha ha
Thanks

fontanalis

sbsquarepants wrote: »

Eh, i dont! Besides i see in the conpiracy theories forum today that there are 2 suns now, apparently they hide the second one from us using airplanes for reasons that didn't quite make sense. So who knows:)

Sorry for dragging this off topic but could osmeone go over there and set the poor fella straight, it's like watching the David Brent dance.

Kevster

No he's correct - there are two Suns. The other one is here in my pockett but it's too bright to takle out. It'd just blind you all. Back to reality, scientists have speculated about there being a companion star to our Sun, but it's never been found yet.

As a side-note, there can be only ONE Sun. The Sun is unique, which is why it gets a capital 'S' when it appears in literature. It is simply the star that exists in our solar system. It is like there is only one 'Kevin' (i.e. me), one 'Universe' (although some would disagree), and one 'The Fonze'.

Kevin