Pass+unobserved
21Tube sound — (or valve sound) is the characteristic sound associated with a vacuum tube based audio amplifiers. Some audiophiles prefer the sound that is produced by the distortion characteristics of tube based amplifiers. The audible significance of tube… …
22Physical Sciences — ▪ 2009 Introduction Scientists discovered a new family of superconducting materials and obtained unique images of individual hydrogen atoms and of a multiple exoplanet system. Europe completed the Large Hadron Collider, and China and India took… …
23Dark matter — Not to be confused with antimatter, dark energy, dark fluid or dark flow. For other uses, see Dark Matter (disambiguation) …
24Force — For other uses, see Force (disambiguation). See also: Forcing (disambiguation) Forces are also described as a push or pull on an object. They can be due to phenomena such as gravity, magnetism, or anything that might cause a mass to accelerate …
25Space debris — populations seen from outside geosynchronous orbit (GEO). Note the two primary debris fields, the ring of objects in GEO, and the cloud of objects in low earth orbit (LEO) …
26Axion — Infobox Particle name = Axion status = Hypothetical interaction = Gravity, Electromagnetic theorized = 1977, Peccei and Quinn mass = 10−6 to 1 eV/c2 electric charge = 0 spin = 0The axion is a hypothetical elementary particle postulated by Peccei… …
27Partners in Crime (short story collection) — infobox Book | name = Partners in Crime title orig = translator = image caption = Dust jacket illustration of the US (true first) edition. See Publication history (below) for UK first edition jacket image. author = Agatha Christie cover artist =… …
28USS Tennessee (BB-43) 1944 — This article is about the USS Tennessee (BB 43), a U.S. Navy battleship, during the year 1944.1944Marshall IslandsIn the early morning of 13 January 1944, Tennessee set her course for Hawaii with Task Unit 58.5.1 and anchored in Lahaina Roads off …
29Textile preservation — refers to the processes by which textiles are cared for and maintained to be preserved from future damage. The field falls under the category of art conservation as well as library preservation, depending on the type of collection. In this case,… …
30Council House Fight — Part of the Indian Wars The Plaza and the Council House in San Antonio …
