Problem: Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus.
What color shift indicates that space objects date from the early days of the universe?
The answer is the following: red

Problem: Allied submarines did not adopt a defensive posture and wait for the enemy to attack. Within hours after the Pearl Harbor attack, in retribution against Japan, Roosevelt promulgated a new doctrine: unrestricted submarine warfare against Japan. This meant sinking any warship, commercial vessel, or passenger ship in Axis-controlled waters, without warning and without help to survivors.[nb 13] At the outbreak of the war in the Pacific the Dutch Admiral in charge of the naval defense of the East Indies, Conrad Helfrich, gave instructions to wage war aggressively. His small force of submarines sank more Japanese ships in the first weeks of the war than the entire British and US navies together, an exploit which earned him the nickname "Ship-a-day Helfrich". The Dutch force were in fact the first to sink an enemy warship; On 24 December 1941, HNLMS K XVI torpedoed and sank the Japanese destroyer Sagiri.
Who was the Dutch Admiral in charge of the East Indies?
The answer is the following: Conrad Helfrich

Problem: According to the apocryphal Gospel of James, Mary was the daughter of Saint Joachim and Saint Anne. Before Mary's conception, Anne had been barren and was far advanced in years. Mary was given to service as a consecrated virgin in the Temple in Jerusalem when she was three years old, much like Hannah took Samuel to the Tabernacle as recorded in the Old Testament. Some apocryphal accounts state that at the time of her betrothal to Joseph, Mary was 1214 years old, and he was thirty years old, but such accounts are unreliable.
How old was Mary when she was consecrated as a virgin?
The answer is the following: three years old

Problem: In the late renaissance various writers began to question the medieval and classical understanding of knowledge acquisition in a more fundamental way. In political and historical writing Niccolo Machiavelli and his friend Francesco Guicciardini initiated a new realistic style of writing. Machiavelli in particular was scornful of writers on politics who judged everything in comparison to mental ideals and demanded that people should study the "effectual truth" instead. Their contemporary, Leonardo da Vinci (14521519) said, "If you find from your own experience that something is a fact and it contradicts what some authority has written down, then you must abandon the authority and base your reasoning on your own findings."
When was da Vinci born?
The answer is the following:
1452