Chatting with Rob about Relative Density @icansciencethat

Uploaded April 2021 | Updated September 2026, 1 week ago

Rob Parks is an astronomy educator and college professor.
We plan to talk about "Relative Density" vs gravity.

Chatting with Rob about Relative Density

$Generalized Sagnac Effect Part 2 Digging a little deeper into the Wang 2004 paper This time, lets try to account for the index of refraction of the fiber optic cable as well as its speed as it goes around the racetrack. Spoiler Alert: It doesnt work. You cannot add the speed of the medium to the speed of light and expect that to work. Without SR, the explanation for this is a bit lacking, but this shows its true.$

Horizon Side-To-Side Curve on Sphere Earth (Simulation)

Review of Generalized Sagnac Effect by Wang, Zheng, and Yao

$Why is perspective? Perspective means things look smaller in the distance, but WHY? What causes perspective? jump ahead: @0:00 Intro @1:07 Perspective is based on simple principles @1:46 Refraction is different from perspective @2:05 Begin with a point light source @3:01 A pinhole camera (diagram) @5:33 Deriving the equations from the diagram @7:35 Forced perspective example @8:28 Deriving the equation for apparent height vs distance @10:27 Angular size @12:03 Equation for angular size @12:30 Curved horizons are not perspective @12:50 Other false claims about perspective @13:41 Rebuttal: Vision is light hitting your eyes @14:06 Rebuttal: Bending light is called refraction - not perspective @14:21 Rebuttal: Orthographic views are not dishonest @15:20 Rebuttal: Accurate graph of apparent height vs distance including perspective @15:25 Rebuttal: What compression actually means in this context source material: How To Draw Using 1-Point Perspective by Circle Line Art School: https://www.youtube.com/watch?v=XRrKohWdpeQ Forced perspective photography with action figures by Wire Hon: https://www.instagram.com/WireHon/ Lake Pontchartrain Transmission Lines Nikon P900 (3/3) - (Flat Earth Debunked) by Soundly https://www.youtube.com/watch?v=kADO7nkt-rk Lens Compression Doesnt Exist - Heres Why by Fstoppers: https://www.youtube.com/watch?v TTXY1Se0eg My previous video on experimental investigation of perspective: https://www.youtube.com/watch?v=n9co3x6Fdbc$

Live Discussion with Bev about the Level Test