The axis of the rotating bullet is constantly directed along the flight of the bullet. Therefore, a bullet in a circular orbit around the Sun is not pointed at a single point on the Celestial Sphere. Therefore, the Earth axis (in orbit around the Sun) should make a full circle (with an angular radius of about 23 degrees) for one year cycle. Why does the Earth axis look at the North Star, and does not draw this huge annual circle across the sky?
First of all, as others have pointed out,
the "axis of the rotating bullet is" NOT "constantly directed along the
flight of the bullet" but remains parallel to the direction it had when it left the barrel.
So "annual circle" does not have "an angular radius of about 23 degrees" but always has the
diameter of the earth's orbit around the sun.
Hence the Earth's axis looking at the
North Celestial Pole does draw a huge annual circle across the sky - it is slightly elliptical, but almost a circle.
The earth's axis remains in the same direction with respect to
Polaris, just as the bullet remains pointed in the same direction relative to the direction it left the barrel.
And no-one is claiming that the earth axis points at
precisely the same location on the "Celestial Sphere".
Short answer:The earth's orbit is about 300 million kilometres, (near enough to 10 light-seconds) across.
Polaris (the North Star) is about 323 lt-yrs away, though you will find it often given 433 light-years (an older estimate).
Hence the angle change over half a year needed to keep point precisely to
Polaris would be about (10 light-seconds)/(323 light-years) or 0.02 arc-seconds.
That is an extremely small angle, equivalent to viewing a Euro Cent coin
of 16.25 mm diameter at a distance of
166 km!
A bit on units used for these tremendous distances:The distance to stars is commonly specified as their
paralax angle.
This the angular change that would occur if the earth moved by the average radius of the orbit around the sun. This radius is defined as the Astronomical Unit, or AU.
And since these angles are all so small, they are usually specified in thousandths of an arc-second or an
mas.
If you look up Polaris in either Wikipedia or and an Astronomy site you will find "Parallax (π): 7.54 ± 0.11 mas" (that is for the 433 ly distance).
In
Wikipedia the distance given as "Distance 323–433 ly or (99–133 pc)".
The 433 ly is the old estimate and 323 ly is from the latest orbiting cameras.
The 99 pc and 133 pc figures are those same distances expressed in units of "parsecs", which is the distance for which the parallax angle is 1 second of arc.
One
parsec is 3.26156 light-years.
I hope I haven't screwed up the 433/323 light year figures anywhere!
It is confusing, but these distances cannot be measured precisely and for most purposes, it simply does not matter.
Long answer:Then let's sort out another little point before some pedant, like me, comes along and says that the earth's axis does not point quite to
Polaris, but at a point about 0.74° from Polaris.
But I'll still refer to
Polaris to save any confusion.
Now let's look at the scales involved.
The diameter of this circle is near enough to 300,000,000 km.
The
latest estimate of the distance to the (current)
Polaris is roughly 323 light-years from the sun and Earth.
The best estimate of the distance to
Polaris is 323 light-years (though you will often see 433 light-years, an older estimate).
I say
estimate because there is no way to measure distances this large with precision.
We could work in kilometres, but the numbers are so
horrendously large that is might be better to use light-years as out distance measure.
One light year is
(velocity of light in km/s) x (seconds in one year) or 9,461,000,000,000 km or 9.461 × 10
12 km.
So this circle described has a diameter of 300,000,000 km or close enough to 1000 light-seconds or 1000/(86,400 x 365.224) =
0.0000317 light-years.
But
Polaris is about
323 light-years from the Solar System,
so from earth it looks as though the earth's axis is always aimed at the same point to within an angle of (0.0000317/323) radians or
0.020 seconds of arc.
There is obvious fact: axis of Earth rotation must not be pointed at the area of North Star during one year cycle. But it is pointed. Thus, the official Science either lies or is incompetent. Correct? Yes. And the Flat Earth model is consistent with Nature here.
No, not correct, as seen above.
USED THEOREM:
The axis of the revolving bullet is constantly directed along the flight of the bullet.
No, it doesn't! It remains parallel to its original direction.
<< I don't believe any of this is now relevant >>
Almost this same problem plagued astronomers and philosophers from about 250 BC.
Aristarchus suspected the stars were other suns that are very far away, and that in consequence there was no observable parallax, that is, a movement of the stars relative to each other as the Earth moves around the Sun. Since stellar parallax is only detectable with telescopes, his accurate speculation was unprovable at the time.
But since this stellar parallax was so small it could not be observed by those early astronomers or even by Tycho Brahe in the late 1500s.
It was not detected till well after the development of the astronomical telescope (Galileo, Newton etc) that Bessel in 1812 measured steller parallax in 61 Cygni.