Editing 2770: Tapetum Lucidum

{{comic
| number    = 2770
| date      = May 1, 2023
| title     = Tapetum Lucidum
| image     = tapetum_lucidum_2x.png
| imagesize = 412x492px
| noexpand  = true
| titletext = Using a reflective wall in a game to give one shot two chances to hit is called a double-tapetum lucidum.
}}

==Explanation==

{{w|Bill Nye}}, perhaps best known for his children's educational series ''{{w|Bill Nye the Science Guy}}'', wearing the same lab coat as in [[200: Bill Nye]], beats an unseen player (presumably [[Randall]]) in an online multiplayer game resembling {{w|XPilot}}, in which players pilot spaceships using simulated rocket physics and attempt to shoot and kill each other. During a laser battle, Bill Nye provides a scientific explanation for the {{w|tapetum lucidum}}, the layer behind the {{w|retina}} of a cat's eye. He explains that the layer reflects back some of the light that passes through the retina, giving it a second chance to hit the retina again. This allows a cat's eye to capture more light than it otherwise would, and thus improves their night vision. It's also why [https://carnegiemnh.org/meowfest-why-do-cat-eyes-glow-in-the-dark/ cat's eyes appear to glow in the dark]. 

At the same time, Bill Nye's battle tactic in the online game perfectly analogizes the point he is making. His spaceship is firing energy pulses into the path of an approaching ship in an attempt to destroy it. Due to the difficulty of hitting a small, fast-moving target, it's likely that most or all of these shots will miss. However, because Bill Nye is firing at a reflective wall, each shot that misses bounces back into the path of the opponent's ship, giving it a second chance to hit the target and effectively doubling the density of the firepower. With double the number of shots to avoid, the opponent's ship is hit and explodes. This explanation is similar to how Bill Nye would explain scientific concepts by using analogous demonstrations of other things. 

In the analogy, the weapon shots fired by Bill Nye's ship are the light photons entering the cat's eye, the reflective wall is the tapetum lucidum, and the opponent's ship is a retinal cell. Destroying the opponent's ship with a shot is analogous to a light photon being absorbed by the cat's retina (and therefore seen). If the reflective wall hadn't been there, the ship might have survived, which means the retina would never have seen that photon.

Randall presumably considers this "extra infuriating" because Bill Nye is showing off his scientific knowledge in some other field while also beating him in the game.

The title text is a pun that refers to "tapetum lucidum" and uses "double tap" in the way that online games, memes, and films refer to shooting something twice in rapid succession to ensure its demise.  This phrase is used in the film ''Zombieland'', and is the subtitle of the 2019 "Zombieland: Double Tap" sequel.

==Transcript==
:[The comic is in four panels. In the first panel, we are watching a simple 2D video game, with triangular rocketships flying around a simple maze, firing green missiles at each other while trying to avoid being hit. The missiles are bouncing off the maze walls. One of the ships is faring much better than the other, and a voice is emanating from it.]
:First rocketship: Cats have a shiny layer behind their retina called the tapetum lucidum.
:Missile sounds: Pew pew pew

:[In the second panel, the second rocketship continues to struggle, while the first maintains its advantage.]
:First rocketship: After light passes through the retina, this layer reflects it back through a second time.
:Missile sounds: Pew pew

:[In the third panel, the first rocketship wins the game. One of its missiles has ricocheted off the maze walls and slammed into the second rocketship, destroying it.]
:First rocketship: This extra bounce gives photons another chance to interact with the retinal cells...
:Second rocketship, exploding: BOOM!

:[In the fourth panel, we see one of the players of the video game sitting at his computer. As the caption makes clear, this is Bill Nye. He finishes his thought.]
:Bill Nye: ...Improving their night vision! Isn't science cool?
:Caption: There's something extra infuriating about losing online games to Bill Nye.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring real people]]
[[Category:Video games]]
[[Category:Biology]]
[[Category:Cats]]