A change in any of these variables will alter the view because what you see depends on the angle at which the Moon’s light strikes the water. Generally, the shape of the path is slightly elliptical with tapered ends, but its appearance depends on the Moon’s altitude, the inclination of the wave faces, and your position. Under some conditions, though, you may have difficulty detecting any difference in brightness along the Moon’s glitter path. This is the point where you would see a single lunar reflection if the water were calm. The path’s most intense portion lies at the same angle below the shoreline as the light source lies above it. The myriad images, all puckered and distorted by the water’s motion, combine along our line of sight to the Moon to create the long and shimmering spectacle that resembles a fallen wedding veil. Each miniature surface creates its own reflection of our satellite’s whole appearance. When the water is choppy, though, moonlight glints off the countless mirrorlike facets that exist in the small waves and ripples. In still water, we see only a single, undistorted reflection of the Moon. Watch especially to see how its appearance changes over time and with the lunar phases. Your mission, should you choose to accept it, is to record subtle details about this phenomenon. This is the Moon’s “glitter path” - a technical term - and it has inspired authors and artists alike over the centuries.
If you are near a large body of rippling water and the Moon is looming low in the sky above it, you may see a long trail of shimmering light on the water’s surface. Scott Momaday, “The Delight Song of Tsoai-talee” Every two weeks, we have to look in the opposite direction to see the Moon, and the ground beneath our feet is then tilted the opposite way as well.- N. The tilted ramp works the same as the tilted “platform” of the Earth beneath our feet. If you turn around, the horizon appears to tilt the opposite way. In front of you, the horizon looks higher on the right and lower on the left. Earth has a tilt of 23.5 degrees on its axis, which means that when we observe the Moon from Earth, it’s a little like we’re standing sideways on a ramp. The tilt of the Moon’s orbit contributes to this, but it’s mostly due to the tilt of our Earth. We call this motion “libration in latitude.”įinally, the Moon appears to tilt back and forth like a metronome.
The 5 degree tilt of the Moon’s orbit also causes it to appear to nod, as though it were saying “yes.” The tilt sometimes brings the Moon above Earth’s northern hemisphere, and sometimes below Earth’s southern hemisphere, allowing us to see slightly more of the northern or southern hemispheres of the Moon.
We call this motion “libration in longitude.” When the Moon is farthest from Earth and orbiting at its slowest, its rotation gets a little ahead, and we see a bit more of its western side. When the Moon is at its closest to Earth and moving most quickly along its orbital path, the Moon itself doesn’t rotate quite fast enough to keep entirely the same side facing us, and we get to see a little more of the eastern side of the Moon. The Moon’s rate of rotation around its own axis, though, always stays the same. Because the Moon's orbit is not perfectly circular, its distance from Earth and its speed in orbit both change slightly throughout the month.
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