Post by: STxAxTIC on November 20, 2020, 12:05:34 pm
Punchline first: The "year" you've pictured your whole life is *technically* wrong, and my clock program will prove it to you.
Taking a coordinate system where the sun is stationary, note that the earth does *two* things: it revolves (around the sun) and it rotates (about its center axis, the 23-degree tilt does not matter). Now check it out: If the earth did not rotate at all, then the "standard" year would be 365.25 days, that's fair. However if you factor in the rotation of the earth, you will get plus or minus one full day, depending on if the rotation direction opposes or agrees with the revolution direction.
The *actual* number of days in the year cannot be 365.25, it must be 364.25 or 366.25. So which is it? Let's ask Google whether the rotation direction of the Earth is the same as its revolution direction, because surely that's been measured. The top result asserts:
Quote
One of the most remarkable features of our solar system is that nearly all of the revolutions and rotations are in the same direction.
So then, it just so happens that the rotation is "helping" the revolution, speeding the year up. The truth, boys, is that there are 364.25 days in one year.
Don't believe me yet? I'm going to attach a screenshot of the curious clock just posted on a neighboring thread. We have an analog clock, with the minute hand attaching to the top of the hour hand, and the second hand attaching to the minute hand. This is analogous to a solar system, where one hand is "in orbit" with respect to its parent. Of course, again just like the solar system, the rotation direction of each hand is in agreement.
The red circles track the hours 1-12, no problem there... But watch the minute hand. It's an honest minute hand: up means 12, down means 6, just like a regular clock. However, when we count the number of "loops" the minute hand makes per 12 hours, we clearly get 11, not 12. What? The pattern followed by the minute hand repeats precisely 11 times. Not what you would expect on a 12-hour clock.
The remedy to all this is even more subtle than the problem. The reason there are not *actually* 11 hours per half-day, is because analog clock hands are always printed on some kind of reference frame. There is always some indication of where 12 is, and from there, you can map the entire face of the clock. You can even build the clock, rotate it any way you want, it it will still be accurate. Whenever you move the clock, you drag the coordinate system around with it.
When it comes to defining the astronomical year, the local solar system doesn't have a notion of "12 o'clock". The best thing we can do is draw an imaginary line between Earth and the sun on any particular day (easily done with mountains, megaliths, and their shadows), and then wait for that moment to repeat itself, calling that moment "one year later". Indeed, this is where the Earth year of 365.25 days comes from. It's measured from Earth on a moving coordinate system. Okay, so for *our* Earthly purposes, there are 365.25 days per year. Take your calendars out of the recycle bin, everything is fine.
So why is that somehow wrong, and what's this 364.25 business? It's the length of an Earth year when you fix an absolute coordinate system. That is, if I took something "fixed", like the stars, and measured all of my coordinates from those, then I would look at Earth and surely measure the length of the year to be 364.25 days. (If Earth rotated backwards, I would get 366.25, but it doesn't.)
Who needs this? People who study cosmic rays. If your concern is massive particle beams whizzing through space, you shouldn't be trying to tune everything on "Earth time". Instead, they have a thing called "Anti-sidereal time":
Anti-sidereal time (https://en.wikipedia.org/wiki/Anti-sidereal_time#:~:text=Anti%2Dsidereal%20time%20and%20extended,year%20of%20solar%20time%2C%20365.25.)
... Anyway, at the very least, I hope you can see why my 12-hour clock seemingly runs on an 11-hour cycle.
EDIT: Code:
Code: QB64: [Select]
- _TITLE "Very Analog Clock"
- SCREEN MainScreen
- TYPE TimeValue
- TYPE Vector
- TYPE ClockHand
- Center AS Vector
- HandPosition AS Vector
- HourHand.Center.x = 0
- HourHand.Center.y = 0
- HourHand.Length = 140
- MinuteHand.Length = HourHand.Length / phi
- SecondHand.Length = HourHand.Length / (phi ^ 2)
- _DEST BackScreen
- CALL UpdateClock
- CALL UpdateClock
- _DEST MainScreen
- CALL UpdateClock
- CALL DrawClockHands
- _LIMIT 60
- SUB UpdateClock
- HourHand.Angle = -((TheTime.Hour + (TheTime.Minute / 60)) / 12) * 2 * pi + pi / 2
- MinuteHand.Angle = -((TheTime.Minute + (TheTime.Second / 60)) / 60) * 2 * pi + pi / 2
- SecondHand.Angle = -(TheTime.Second / 60) * 2 * pi + pi / 2
- MinuteHand.Center.x = HourHand.HandPosition.x
- MinuteHand.Center.y = HourHand.HandPosition.y
- SecondHand.Center.x = MinuteHand.HandPosition.x
- SecondHand.Center.y = MinuteHand.HandPosition.y
- SUB DrawClockHands
- CALL lineSmooth(SecondHand.Center.x, SecondHand.Center.y, SecondHand.HandPosition.x, SecondHand.HandPosition.y, SecondHand.Shade)
- CALL lineSmooth(MinuteHand.Center.x, MinuteHand.Center.y, MinuteHand.HandPosition.x, MinuteHand.HandPosition.y, MinuteHand.Shade)
- CALL lineSmooth(HourHand.Center.x, HourHand.Center.y, HourHand.HandPosition.x, HourHand.HandPosition.y, HourHand.Shade)
- TheTime.Hour = t \ 3600
- t = t - TheTime.Hour * 3600
- TheTime.Minute = t \ 60
- t = t - TheTime.Minute * 60
- TheTime.Second = t
- 'translated from
- 'https://en.wikipedia.org/w/index.php?title=Xiaolin_Wu%27s_line_algorithm&oldid=852445548
- SWAP x0, y0
- SWAP x1, y1
- SWAP x0, x1
- SWAP y0, y1
- dx = x1 - x0
- dy = y1 - y0
- gradient = dy / dx
- gradient = 1
- 'handle first endpoint
- yend = y0 + gradient * (xend - x0)
- xpxl1 = xend 'this will be used in the main loop
- plX = ypxl1
- plY = xpxl1
- GOSUB plot
- plX = ypxl1 + 1
- plY = xpxl1
- GOSUB plot
- plX = xpxl1
- plY = ypxl1
- GOSUB plot
- plX = xpxl1
- plY = ypxl1 + 1
- GOSUB plot
- DIM intery
- intery = yend + gradient 'first y-intersection for the main loop
- 'handle second endpoint
- DIM xpxl2, ypxl2
- yend = y1 + gradient * (xend - x1)
- xpxl2 = xend 'this will be used in the main loop
- plX = ypxl2
- plY = xpxl2
- GOSUB plot
- plX = ypxl2 + 1
- plY = xpxl2
- GOSUB plot
- plX = xpxl2
- plY = ypxl2
- GOSUB plot
- plX = xpxl2
- plY = ypxl2 + 1
- GOSUB plot
- 'main loop
- DIM x
- plY = x
- GOSUB plot
- plY = x
- GOSUB plot
- intery = intery + gradient
- plX = x
- GOSUB plot
- plX = x
- GOSUB plot
- intery = intery + gradient
- plot:
- ' Change to regular PSET for standard coordinate orientation.
Post by: DANILIN on November 20, 2020, 12:53:11 pm
[ This attachment cannot be displayed inline in 'Print Page' view ]
Post by: _vince on November 20, 2020, 04:01:23 pm
3d visualization from Russia 1/3 MB
Nice! Which Russian space probe was this filmed from?
Post by: SMcNeill on November 20, 2020, 04:30:07 pm
None.
The Earth is stable and unmoving — it’s the rest of the universe that’s rotating around us. How else do you think people keep from flying off, or getting dizzy, from all that spinning?
Post by: TempodiBasic on November 20, 2020, 05:54:32 pm
I think that we must ask to Focault another pendulum more sophisticated versus the first!
But is that linear movement of the Sun in what direction in respect of Milk galaxy?
A very fashinated person by Astronomy
Post by: SierraKen on November 20, 2020, 06:52:44 pm
Post by: david_uwi on November 21, 2020, 11:14:43 am
Post by: STxAxTIC on November 21, 2020, 12:52:31 pm
Nice to hear from you by the way! I still remember your... what was it... very fast square root function or something, back on *.net like 5.5 years ago.
Post by: FellippeHeitor on November 21, 2020, 02:36:23 pm
Post by: STxAxTIC on November 21, 2020, 02:51:22 pm
I guess the image was still technically sent from Russia...
That video goes super new age the minute it says "vortex". Ahem, if I take circular motion, and then stretch it out, that's a helix, not a vortex. Two totally different things. Then they wanna show us flowers and imply some kind of lesson there... Watch for psuedoscience, folks. No real connection going on between the things in the video.
Post by: FellippeHeitor on November 21, 2020, 03:03:29 pm
Post by: johnno56 on November 21, 2020, 08:07:08 pm
Interesting tidbits... Did you know that a "day" on Venus is longer than it's "year" and it rotates in the opposite direction to all the other planets and it is hotter than Mercury. We have never yet seen Pluto complete a full "year". The Earth's axis "tilts" at about 23 degrees (reason for seasons) but Uranus tilts at about 97 degrees. Which means it "North Pole" points towards the Sun. Which means it kind of "rolls" around the Sun.
So I'm a nerd...
J
Post by: doppler on November 21, 2020, 09:18:28 pm
And I am sticking to it. On the flat side of earth my butt is in. I still insist if you dig a hole straight down to the other side. And jump in gravity will take you to the other side where you arrive all crispy from the magma.
Post by: johnno56 on November 22, 2020, 12:51:51 am
Post by: OldMoses on November 22, 2020, 08:20:55 am
Damn, now I have to change all the rotation parameters in my system simulator. Gee, thanks alot. ;)
Post by: david_uwi on November 22, 2020, 08:45:02 am
Post by: STxAxTIC on November 22, 2020, 09:12:44 am
The first thing that helped me wrap my head around this went something like this...
For so-called tidal lock (which thank god we don't have), there would be one long, infinite day, and the notion of "year" is undefined unless you somehow introduce more reference vectors (i.e. directions to stars, cosmic rays).
Next I imagine a different case with one day taking one year to complete. To do this, I keep the earth fixed, i.e. no rotation at all, and then translate it in an orbit around the sun. This will give the apparent view of a sunrise, sunset, etc.
So the trick *just* happened if anyone missed it. We have a case of an earth that does *not* rotate, but it experiences a single day *anyway*.
Now build from there. Suppose we "tune in" exactly one rotation of the planet as we drag it around the sun. Fine, like before, I translate it around a rough circle while twisting it once. As viewed from earth, there are now *two* days, but we only forced *one* rotation.
This off-by-one error goes all the way up to 365 +/- 1. The sign is determined by whether or not the rotation and revolution axes are in agreement.
Post by: doppler on November 22, 2020, 10:54:17 am
For so-called tidal lock (which thank god we don't have)Somewhat wrong. In our part of the galaxy there is tidal lock. It's the moon. If the moon's rotation was not locked to earths rotation we would get to see the scared backside. If you compare front (earth facing) to backside. The moon is really scary. Consider this, any hits on earth facing side had to get near earth at one time in the meteor orbit. The backside just get hits, and is the likely target of all meteors.
Post by: doppler on November 22, 2020, 11:12:05 am
all the other planets ......We have never yet seen Pluto complete a full "year".
So I'm a nerd...
J
Well you are behind in the times. Pluto is no longer a planet and just a name of a dog now. We have 8 planets, and a big icy rock. Don't start up about Pluto is really a planet and not a rock. Out beyond Pluto's orbit there are dozens of bigger rocks found orbiting the sun. They are all numbered and not named. AND not planets.
I became a BIGGER nerd than you now.
Get the nerd meter out and let's measure them.
Post by: STxAxTIC on November 22, 2020, 11:43:59 am
I appreciate what you add to the discussion about the moon, which happens to be in tidal lock with the earth. Excellent.
To be clear though, I was saying that if the earth had a locking relationship with the sun, life would be pretty tough, only possible near the perpetual twilight.
Post by: OldMoses on November 22, 2020, 01:25:39 pm
This off-by-one error goes all the way up to 365 +/- 1. The sign is determined by whether or not the rotation and revolution axes are in agreement.
In that case, Venus and Uranus would be (+), with all the others being (-), they being the only planets who's rotation is retrograde with respect to their orbits. Uranus is a little odd with its axial inclination being less than a degree from the ecliptic. It may not have been retrograde at some point if it has wobbled.
Post by: doppler on November 22, 2020, 02:17:03 pm
Post by: TempodiBasic on November 22, 2020, 07:07:17 pm
with the dark side of moon and your affirmations about it NOW we know that aliens couldn't have their secret base there!
So the moon is our lighting rod of meteors.... :-) We are so lucky
Pluto is the dog of mickye mouse, but where is the Xplanet in our solar system? https://en.wikipedia.org/wiki/Planets_beyond_Neptune#Planet_X (https://en.wikipedia.org/wiki/Planets_beyond_Neptune#Planet_X)
Post by: doppler on November 22, 2020, 08:14:18 pm
Xplanet
Ya, just had to go there didn't cha.
Post by: johnno56 on November 23, 2020, 12:16:21 am
Post by: TempodiBasic on November 23, 2020, 02:16:17 pm