Brightest in the Dark Trivia Quiz

Answer: Rods

The retina is at the back of the eye and is covered in structures known as rods and cones. Cones operate in brighter light conditions and give color vision. Rods are more sensitive in low light conditions but only give vision in black and white. As the light level rises above a threshold that is generally as bright as a clear starry sky, more cones "turn on" and color vision at night improves.

Answer: Red

Red is at the lower end of visible light frequencies and has a lesser impact on human night vision than other colors. Red is mostly absorbed by the cones on the retina and does not affect the rods that are important to night vision. The human eye also produces the pigment rhodopsin at night to improve vision, and red light does not interfere with that process.

People preparing to work in low light conditions often wear red-tinted goggles beforehand when still in brighter conditions to help the eye change for optimal night vision. Lights fitted with red bulbs or covers, or flashlights with red lenses can provide illumination without significantly impacting the changes made in the eye.

Answer: Objective lens diameter

The objective lenses are usually the larger lenses on binoculars, those farthest away from the eyepiece lenses you look through. Larger diameter lenses allow more light to enter the field of view, improving performance in low light. A technique to increase the amount of light seen by the binocular user at night is to keep approximately 2/3 of the field of view the sky and 1/3 water or land.

Answer: Torpedoes

WW2-era submarines spent most of their time on the surface since they had much greater speed and endurance on the surface than submerged. Obviously, surface attacks were better done at night when the relatively small and low-profile submarines had an advantage against traditional surface ships.

The UZO ("Underwasserzieloptik" or "U-boat Target Optic") was a large-diameter set of waterproof binoculars that were attached to a fixed pedestal that could be rotated to follow target ships. The rotation of the UZO automatically fed information to the torpedo aiming computer. The UZO had high-quality lenses, special coatings to maximize light transmission, and were pressurized with inert gases to prevent fogging and water intrusion. With the UZO, surfaced submarines could operate on the darkest nights to identify targets and launch torpedoes, often before the U-Boat was detected by the target or escorting warships.

Answer: Infrared

Infrared is the band of radiation just below visible light. Being of longer wavelengths and lower frequency it cannot be seen by humans. Infrared was discovered in the 1800s by the effect it had on a thermometer. Thermal imaging uses elements that are sensitive to infrared radiation transmitted or reflected by organisms, machines, or other devices.

Answer: Identification by friendly forces

Modern infrared night vision gear is expensive and complex and so tends to be used by technologically advanced forces. Troops using this gear "own the night" and can operate when forces that do not have that gear are at a serious disadvantage. When operating against an enemy that does not have night vision capability, troops that do have that capability often wear IR-reflective patches.

This means that they can be easily identified as friendly by their allies using night vision.

Answer: Tritium

Tritium, also known as hydrogen-3 or 3H, is mainly produced in nuclear reactors, although small amounts do occur naturally. Tritium is extremely expensive, around $30,000 U.S. dollars per gram in 2025. However, very small amounts are used in commercial applications, and the world-wide annual demand for tritium is for less than one-half kilogram. Tritium is combined with a phosphorescent material, and the beta particles released by the tritium cause that material to emit low-level light that is easily seen in the dark.

Answer: Aircraft

Low Altitude Navigation and Targeting Infrared for Night, or LANTIRN, was developed in the 1980s and is still used on US-made military jet aircraft. The earliest LANTIRN was the first use of Forward-Looking Infrared (FLIR) sensors in tactical aircraft. The LANTIRN pods are externally mounted on the aircraft. A navigation pod includes an infrared sensor and terrain-following radar that allows the aircraft to fly at low altitudes above the ground, at night, and in poor weather.

A separate targeting pod contains a high-resolution FLIR, laser rangefinder, and software to track moving targets. These systems aren't cheap: in 2025, the navigation pod costs about $1.3 million, and the targeting pod about $3.2 million.

Answer: Red

Infrared devices detect wavelengths longer than red light but, since they are adjacent frequencies, red needs to be filtered from light sources used with infrared night vision devices. Flashlights, lighting fixtures, etc. designed for use with night vision devices are usually blue, or may be white with special filters to remove the red light.

Answer: SLAR

Night Vision Device (NVD), Night Observation Device (NOD) and Enhanced Vision System (EVS) are common acronyms that refer to various technologies to improve human sight at night or in low-light conditions. Another common acronym is NVG for Night Vision Goggles/Gear.

However, SLAR is Side-Looking Airborne Radar, that is typically used to create radar images of the ground or water surface from an aircraft.