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Inspired by: [Simulating the solar system with 70 lines of Python code](https://chongchonghe.github.io/computational-science/python/animation/2022/08/25/python-solar-system.html)

and: [Introduction to raytracing](https://www.scratchapixel.com/lessons/3d-basic-rendering/introduction-to-ray-tracing/how-does-it-work.html)

I modified the [code](https://github.com/scratchapixel/scratchapixel-code/tree/main/introduction-to-ray-tracing) from the above article to raytrace the solar eclipse by simulating the motion of Earth/Moon/Sun system, and casting light from the Sun onto the Earth.

Inputs to program:
o Position, velocity, mass, and radius of E/M/S on April 8th, 14:00 UTC.
o Rotation rate of Earth.
o Axial tilt of Earth.
o Date and time of Spring Equinox.
o Force = mass x acceleration
o Force = Gravity-constant x mass1 x mass2 / radius^2
o "Blue Marble" map from https://ian.macky.net/pat/bmarbl/index.html

Start position and velocity data was from: https://ssd.jpl.nasa.gov/horizons/

After initialization, position and velocity data was updated every second for 9 hours using the above Newton force laws. Images were recorded once a minute. Final video was compiled at 60 frames per second, yielding one hour of real time per second of video.

You can compare the raytraced path with this version: https://nso.edu/for-public/eclipse-map-2024/

Preamble
--

Today's topic is a response to @McNasty's challenge[1]:

"chrimony claims that he can calculate exactly how far a star at 500 light years away should appear to move throughout the night"

But the real origins of the question are the star trails that can be seen from Australia[2]. Two poles on a spherical Earth, one pole in Flattard Land.

McNasty tries to cope with his failure to explain half the night sky by claiming[3] because we don't see parallax in star trails, then "If the stars show no movement at all relative to each other, then it means those stars are at the same exact distance from the observer. So basic observation and by the laws of perception, the stars in the night sky are a blanket."

Whatever the fuck it means for the stars to be a "blanket".

My response to this is, "If the perceived parallax for a star is 0, then 0/2 = 0". Meaning a star twice as far away will show no parallax if we can't detect parallax in the closer star.

The closest star is Proxima Centauri, at about 4 light years away. If we can't detect parallax for that star in a 12-hour night sky star trail, then we sure as fuck won't be able to see it for a star 500 light years away. So to give the flattard every advantage, I'm going to calculate the parallax for a star 1 light year away over a 12-hour period.

The Math
--

# Right-angle trigonometry.
# Do flattards know SohCahToa?
parallax angle = arctan( displacement / distance )

# Distance to the star.
# Flattards ignore how big this number is.
distance = 1 light year = 5.88 x 10^12 miles

# The lateral motion of an observer on Earth.
displacement = orbit displacement + rotation displacement in 12 hours

# The Earth spins.
rotation displacement = diameter Earth = 7.93 x 10^3 miles

# How far, in degrees, the Earth moved along its orbit.
# It moves 360° in 365 days.
# 360°/365 in one day.
# And 360°/(365x2) in half a day.
orbit displacement angle = 360° / (365 x 2) = 0.493°

# Convert orbital degrees to lateral motion.
# Some more right-angle trigonometry.
# Radius of Earth's orbit = 93 million miles.
orbit displacement = sin(0.493°) x 93.0 x 10^6 miles = 8.00 x 10^5 miles

# Total displacement (orbit + rotation).
# Note the orbital displacement dominates the displacement due to Earth's rotation.
displacement = 8.00 x 10^5 miles + 7.93 x 10^3 miles = 8.08 x 10^5 miles

# Final calculation!
parallax angle = arctan( displacement / distance )
= arctan( 8.08 x 10^5 miles / 5.88 x 10^12 miles )
= 7.87 x 10^-6°

Or in English terms, approximately 8 millionths of a degree!

Conclusion
--

I don't care how nice the smart phone on your camera is, you aren't going to see any parallax on a 12-hour time lapse video of the night sky taken from your backyard.

Citations:
--
[1]: https://www.upgoat.net/viewpost?postid=65f9e88d087db
[2]: https://www.youtube.com/watch?v=56ZMZtq0qfY
[3]: https://www.upgoat.net/viewpost?postid=65f3085348086

Full video of gem cutting: https://www.youtube.com/watch?v=xr-UNlOWS3Y

More info:

https://nvd.nist.gov/vuln/detail/CVE-2023-45866

"Base Score: 8.8 HIGH"

"Bluetooth HID Hosts in BlueZ may permit an unauthenticated Peripheral role HID Device to initiate and establish an encrypted connection, and accept HID keyboard reports, potentially permitting injection of HID messages when no user interaction has occurred in the Central role to authorize such access. An example affected package is bluez 5.64-0ubuntu1 in Ubuntu 22.04LTS. NOTE: in some cases, a CVE-2020-0556 mitigation would have already addressed this Bluetooth HID Hosts issue."

https://www.thefinalhop.com/understanding-cve-2023-45866-a-critical-bluetooth-security-flaw/

"To address CVE-2023-45866, Google has released patches for Android devices, specifically for versions 11 through 14. These updates are crucial for safeguarding devices against potential exploits. Similarly, while the issue was addressed in Linux in 2020, only ChromeOS among the Linux-based operating systems enabled the fix by default. Other distributions like Ubuntu, Debian, Fedora, Gentoo, Arch, and Alpine did not, leaving them vulnerable​​."

"The vulnerability also affects macOS and iOS devices, especially when a Magic Keyboard is paired. Apple, having been notified by Newlin in August, confirmed the report but has yet to share a timeline for patching the vulnerability."

Gee, I wonder what changed?

Summary: Because blacks under-performed on the test for air traffic controllers, a phony test was put in place and Whites and Asians were discriminated against. Now there are too few air traffic controllers, and the number of close calls/near misses has doubled over the past decade.

Do you believe?