- #1
Mk
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Would this statement be correct?
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Correct me on something about the sun's movement in the sky
In summary: This thread is not about what we think; it is about what we observe. We observe the movement of the sun from our rest frame.Thought so.
- #2
Jimmy Snyder
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Exactly correct from a frame of reference that by December 22nd stops moving north and rests for three days, until December 25th when it moves approximately one degree downwards with respect to the sun.Mk said:
- #3
Bystander
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d(phizenith)/dt ~ 23 ( 2pi/365.25 ) sin ( t 2pi/365.25 ) , where t = days since solstice, or t0 = solstice dates. Highest daily rate of change of zenith angle (elevation) is 1/3 degree per day, and occurs at the vernal and autumnal equinoxes.
- #4
Integral
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As Bystander is trying to say. The Suns motion is sinusoidal, at the solstice it reaches its extreme position for the season. The rate of change is very small at these times (Summer and Winter) So the sun appears to hover briefly as it changes direction. It is not really stationary it is just moving very slowly. It then begins to accelerate, slowly initially, then as it speeds up, reaches the maximum rate of change at the Equinox. At this time the sun races past the equator but even then the rate of change begins to drop as the sun moves toward the other extreme.
- #5
Mk
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Thanks for all three of the replies, I figured it would be sinusoidal motion, and it just slowerly and slowerly moved, until it reversed it's path of acceleration. Thanks for the math, Bystander.
- #6
DaveC426913
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Look up "analemma". That is the name of the sun's figure 8 path against the sky.
- #7
Danger
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Maybe it's just because I was born a non-Terracentric, but I prefer to think that the sun just pretty much stays the same and the motion of the Earth makes it appear to move.
- #8
neutrino
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Heretic!Danger said:
- #9
mplak
Hello to all!
I don't know if anyone will check this but...here is my question:
what is the sun time equation that describes sun's movement ?
I have found plots of sun's height (in degrees) (vertical axes height-horizontal sun azimuth in degrees) but I can't find it's mathematical expression...
I don't know if anyone will check this but...here is my question:
what is the sun time equation that describes sun's movement ?
I have found plots of sun's height (in degrees) (vertical axes height-horizontal sun azimuth in degrees) but I can't find it's mathematical expression...
- #10
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Read post #6.
- #11
BobG
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mplak said:
http://www.analemma.com/Pages/framesPage.html
http://en.wikipedia.org/wiki/Equation_of_time
- #12
Equate
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Danger said:
I was just about to say the same thing.
Thank you.
- #13
DaveC426913
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Equate said:
He's kidding.
This thread is not about what we think; it is about what we observe. We observe the movement of the sun from our rest frame.
- #14
Equate
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Thought so.
It's a big conspiracy. I could have sworn I saw the far side of the moon the other day, but no one believed me.
Oh well...
It's a big conspiracy. I could have sworn I saw the far side of the moon the other day, but no one believed me.
Oh well...
FAQ: Correct me on something about the sun's movement in the sky
1. How does the sun's movement in the sky change throughout the day?
The sun appears to rise in the east and set in the west due to the rotation of the Earth on its axis. This rotation causes the sun to appear to move across the sky, reaching its highest point (known as solar noon) around midday before setting in the west.
2. What causes the sun to appear higher or lower in the sky?
The tilt of the Earth's axis affects the sun's position in the sky. During the summer months, the Earth's axis is tilted towards the sun, causing it to appear higher in the sky. In the winter months, the Earth's axis is tilted away from the sun, causing it to appear lower in the sky.
3. Why does the sun sometimes appear to move in a curved path across the sky?
This is known as the sun's apparent path or ecliptic. It is caused by the combination of the Earth's rotation on its axis and its orbit around the sun. As the Earth moves in its orbit, the sun appears to move in a curved path from our perspective on Earth.
4. Does the sun's movement in the sky change throughout the year?
Yes, the sun's movement in the sky changes throughout the year due to the Earth's tilt and its orbit around the sun. This causes the length of daylight hours to vary throughout the year, with longer days in the summer and shorter days in the winter.
5. How does the sun's movement in the sky differ depending on location?
The sun's movement in the sky can vary depending on a person's location on Earth. For example, someone living closer to the equator will experience more consistent sunrise and sunset times throughout the year, while someone closer to the poles will experience more extreme changes in the sun's movement and daylight hours throughout the year.