what is the name of the large, thin, white circle that sometimes appears around the moon?
481798
A Corona.\n\nThe moon can produce interesting optical effects when conditions are right. The most common of which are moon rings, moon bows, which are similar to rainbows, moon dogs and moon pillars. A rainbow is produced when sunlight is refracted through water droplets - A similar effect is produced when moon light refracts through ice crystals\n\nThe ring around the Moon is caused by the refraction of Moonlight (which of course is reflected sunlight) from ice crystals in the upper atmosphere. The shape of the ice crystals results in a focusing of the light into a ring. Since the ice crystals typically have the same shape, namely a hexagonal shape, the Moon ring is almost always the same size.
289555
The Moon's apparent size is an illusion based on its apparent proximity to other objects (stars, mountains, trees, buildings).  The Moon alone in the "middle of the sky" can seem quite small, but a few foreground objects of the correct relative proportion will impart the illusion.\n\nTo "correct" the illusion, hold your thumb up at arms length and compare it to the moon at different times of the day and night (visibility dependent, of course).
1016790
It's because your mind sees the moon in proportion to landscape features when it is low.  It's kind of an optical illusion - it's not really bigger but your mind interprets it as bigger.
988242
well, its not exactly round, its spherical. but yeah, since you can only see it from one side at a time, if you saw it from space it would appear round. kinda like how the sun appears to us. it looks like its moving, but its not, WE ARE. lol.
8454
Light from the moon passing through Ice crystals in Earth's upper atmosphere.\n\nI have included links to a couple of web pages that include photos and explanations.
410954
The Earth is round.\nObviously at lower latitudes you view the moon from a different angle than what you would at higher latitudes.\nSo that at the equater the moon when rising would look like a bowl from that angle in that phase.
301180
Also, we only see it when it is above the horizon.\n\nDuring the day, the sun is obviously above the horizon.  But the moon sets an hour or so later each day, so sometimes it is below the horizon in the day, and sometimes not.
345859
This is one of the strangest questions I have come across along with.... Where does the moon go at night?
285687
The "ring of fire" that surrounds the eclipse is called the corona.\n\nThe moon is not quite big enough to completely cover the sun and the corona shows around it.
1079025
no it is a reflection of the suns light.  That is why you can still see the moon during the day soemtimes.  It is still getting light from the sun.
158060
The moon is known as the moon, but there are also other names given to it such as: Luna by the Romans and Selene and Artemis by the Greeks. It is also known as one of Earth's satellite. It is the second largest object in the sky and orbit 384,400km from the Earth. Its diametre is 3,476km and it has a mass of 7.35kg. As far as I know there are no other name for the earth's moon persay.
1080564
ok...this is a little complicated. when there is a solar eclipse, only a certain section of the earth can see it because of the angle of light from the sun going around the moon. i cant remember the terminology, but if you look it up on the internet, you could probably find it.
53143
The moon rotates on its own axis and orbitrs the planet Earth as Earth orbits the sun.\n\n\nFrom Wikipedia and verified though other sources:\nThe Moon is Earth's only natural satellite. It has no formal name other than "The Moon", although in English it is occasionally called Luna (Latin for moon), or Selene, to distinguish it from the generic "moon" (natural satellites of other planets are also called moons). Its symbol is a crescent. The terms lunar, selene/seleno-, and cynthion (from the Lunar deities Selene and Cynthia) refer to the Moon (aposelene, selenocentric, pericynthion, etc.).\n\nThe average distance from the Moon to the Earth is 384,403 kilometers (238,857 miles). The Moon's diameter is 3,476 kilometers (2,160 miles).\nThe Moon makes a complete orbit about the Earth approximately once every 28 days. Each hour the Moon moves relative to the stars by an amount roughly equal to its angular diameter, or by about 0.5°. The Moon differs from most satellites of other planets in that its orbit is close to the plane of the ecliptic and not in the Earth's equatorial plane.\n\nSeveral ways to consider a complete orbit are detailed in the table below, but the two most familiar are: the sidereal month being the time it takes to make a complete orbit with respect to the stars, about 27.3 days; and the synodic month being the time it takes to reach the same phase, about 29.5 days. These differ because in the meantime the Earth and Moon have both orbited some distance around the Sun.\n\nThe gravitational attraction that the Moon exerts on Earth is the cause of tides in the sea. The tidal flow period, but not the phase, is synchronized to the Moon's orbit around Earth. The tidal bulges on Earth, caused by the Moon's gravity, are carried ahead of the apparent position of the Moon by the Earth's rotation, in part because of the friction of the water as it slides over the ocean bottom and into or out of bays and estuaries. As a result, some of the Earth's rotational momentum is gradually being transferred to the Moon's orbital momentum, resulting in the Moon slowly receding from Earth at the rate of approximately 38 mm per year. At the same time the Earth's rotation is gradually slowing, the Earth's day thus lengthens by about 15 µs every year. A more detailed discussion follows in the section titled Earth & Moon.\n\nThe Moon is in synchronous rotation, meaning that it keeps the same face turned to the Earth at all times. This synchronous rotation is only true on average because the Moon's orbit has definite eccentricity. When the Moon is at its perigee, its rotation is slower than its orbital motion, and this allows us to see up to an extra eight degrees of longitude of its East (right) side. Conversely, when the Moon reaches its apogee, its rotation is faster than its orbital motion and reveals another eight degrees of longitude of its West (left) side. This is called longitudinal libration.\n\nBecause the lunar orbit is also inclined to the Earth's equator, the Moon seems to oscillate up and down (as a person's head does when nodding) as it moves in celestial latitude (declination). This is called latitudinal libration and reveals the Moon's polar zones over about seven degrees of latitude. Finally, because the Moon is only at about 60 Earth radii distance, an observer at the equator who observes the Moon throughout the night moves by an Earth diameter sideways. This is diurnal libration and reveals about one degree's worth of lunar longitude.\n\nEarth and Moon orbit about their barycenter, or common center of mass, which lies about 4700 km from Earth's center (about 3/4 of the way to the surface). Since the barycenter is located below the Earth's surface, Earth's motion is more commonly described as a "wobble". When viewed from Earth's North pole, Earth and Moon rotate counter-clockwise about their axes; the Moon orbits Ea
629822
Some people incorrectly call the far side of the Moon the dark side of the Moon. The far side is never visible from Earth and the near side is always visible from Earth. But the far side not always dark, just like the near side is not always light.
591541
While refraction by the atmosphere is too small to affect the apparent diameter of the moon except perhaps when it is within one diameter of the horizon (and in this case, the moon will appear stretched a bit in the direction perpindicular to the horizon) it does appear larger to our brains when on the horizon because we see it in reference to distant large objects.  Gives the impression of it looking bigger, however if you could look straight up at the moon, and see a bunch of trees a mile up in sky between you and the moon it would look just as large as when it is near the horizon.  (If you ever do see this by the way, seek shelter or psychiatric treatment immediately!)\n\nThe moons orbit IS elliptical, however, and at times will be closer to the earth than others.  This phenomenon is called "lunation" and there is a great still and a gif animation of this at the Astronomy Picture of the Day.\n\nhttp://antwrp.gsfc.nasa.gov/apod/ap041021.html\nhttp://antwrp.gsfc.nasa.gov/apod/ap991108.html\n\nThe moon's surface brightness (brightness per area) also varies with phase. Because larger particles tend to reflect a bit more light directly back at the light source than in other directions (look up "Mie" scattering) a given bit of the moon will appear brighter when the earth is in the direction of the sun as seen from the moon. (All three are in a line with the Earth more or less between). This occurs when the moon is full or near full. This brightening might make the moon look larger.
790340
Beacause asit goes around the Earth it becomes closer and further away during its cycle.  The moon is in an oval orbit.\nhttp://stardate.org/nightsky/moon/
124988
The moon appears yellow when it is low in the sky (or even orange or red) for the same reason that the sun appears yellow when it is low in the sky (or even orange or red). \n\nNitrogen and oxygen molecules in the air are the right size to scatter away blue light from the mostly white light emitted from the sun (and reflected from the moon). This is called Rayleigh-Tyndall scattering, and there are many answers here dealing with that question. \n\nThis is the reason that the sky looks blue during the day, but during the night, with only the moon for lumination, there is not enough light to brighten the sky sufficiently for us to think it is blue. \n\nWhen the sun and the moon are low in the horizon, the light from these bodies travels through more atmosphere, so more blue light is scattered away, leaving orange or even red light:\n\n1. When the moon or sun is high in the sky:\n\n(whitish light from sun or moon)-(blue light scattered away)= (yellow light)\n\n2. When the moon or sun is low in the sky:\n\n(whitish light from sun or moon)-(more blue light scattered away because sun or moon is lower in sky)= (orange or red light)\n\nIt should be noted that the moon can not only appear whitish, yellow, red or orange, but because of refraction effects, can appear to have a green rim or a red rim (see reference), related to the green flash.\n\nAlso, if there are smoke or dust particles in the air, then instead of Rayleigh scattering, one encounters the phenomenon called nonselective scattering, where the red is scattered away, and the sun or moon appears blue. \n\nRayleigh scattering (blue gets scattered) occurs when the size of the scattering particle is smaller than the wavelength of the light. \n\nNonselective scattering (red gets scattered) occurs when the size of the scattering particle is about the same as the wavelength of the light. \n\nMie scattering (all colors scattered; causes the white of clouds and smoke) occurs when the size of the scattering particle is much larger than the wavelength of light.