String theory String theory was first studied in the late 1960s[3] as a theory of the strong nuclear force before being abandoned in favor of the theory of quantum chromodynamics. Subsequently, it was realized that the very properties that made string theory unsuitable as a theory of nuclear physics made it a promising candidate for a quantum theory of gravity. Five consistent versions of string theory were developed until it was realized in the mid-1990s that they were different limits of a conjectured single 11-dimensional theory now known as M-theory.[4] Many theoretical physicists, including Stephen Hawking, Edward Witten and Juan Maldacena, believe that string theory is a step towards the correct fundamental description of nature: it accommodates a consistent combination of quantum field theory and general relativity, agrees with insights in quantum gravity (such as the holographic principle and black hole thermodynamics) and has passed many non-trivial checks of its internal consistency.
Prenatal memory Prenatal memory, also called fetal memory, is important for the development of memory in humans. Many factors can impair fetal memory and its functions, primarily maternal actions. There are multiple techniques available not only to demonstrate the existence of fetal memory but to measure it. Fetal memory is vulnerable to certain diseases so much so that exposure can permanently damage the development of the fetus and even terminate the pregnancy by aborting the fetus. Background Information and Functions[edit] Fetal memory is integral to mother-infant attachment There is substantial evidence that fetal memory exists within the first and second trimester after conception when the egg is fertilized. Development[edit] The Central Nervous System (CNS) and memory in the fetus develop from the ectoderm following fertilization via a process called neurulation. Functions[edit] Measurement techniques[edit] There are considered to be three paradigms used to investigate fetal learning and memory.
Antimatter In particle physics, antimatter is material composed of antiparticles, which have the same mass as particles of ordinary matter but have opposite charge and other particle properties such as lepton and baryon number. Encounters between particles and antiparticles lead to the annihilation of both, giving rise to varying proportions of high-energy photons (gamma rays), neutrinos, and lower-mass particle–antiparticle pairs. Setting aside the mass of any product neutrinos, which represent released energy which generally continues to be unavailable, the end result of annihilation is a release of energy available to do work, proportional to the total matter and antimatter mass, in accord with the mass-energy equivalence equation, E=mc2.[1] Antiparticles bind with each other to form antimatter just as ordinary particles bind to form normal matter. For example, a positron (the antiparticle of the electron) and an antiproton can form an antihydrogen atom. History of the concept Notation Positrons
Cosmogony Cosmogony (or cosmogeny) is any model concerning the coming-into-existence (i.e. origin) of either the cosmos (i.e. universe), or the so-called reality of sentient beings.[1][2] Developing a complete theoretical model has implications in both the philosophy of science and epistemology. Etymology[edit] The word comes from the Koine Greek κοσμογονία (from κόσμος "cosmos, the world") and the root of γί(γ)νομαι / γέγονα ("come into a new state of being").[3] In astronomy, cosmogony refers to the study of the origin of particular astrophysical objects or systems, and is most commonly used in reference to the origin of the universe, the solar system, or the earth-moon system.[1][2] Overview[edit] The Big Bang theory is the prevailing cosmological model of the early development of the universe.[4] The most commonly held view is that the universe was once a gravitational singularity, which expanded extremely rapidly from its hot and dense state. Cosmologist and science communicator Sean M.
What Wavelength Goes With a Color? Colors We Can't See There are many wavelengths in the electromagnetic spectrum the human eye cannot detect. Energy with wavelengths too short for humans to see Energy with wavelengths too short to see is "bluer than blue". How do we know this light exists? Energy with wavelengths too long for humans to see Energy whose wavelength is too long to see is "redder than red". How do we know this kind of light exists? Very long wavelengths of infrared light radiate heat to outer space. 5/4/94 - Why are different things different colors? (Lansing State Journal, May 4, 1994) When different wavelengths of light hit our eyes, we see different colors. Light from the sun or light bulbs has many different wavelengths. This great mixture of wavelengths is commonly perceived as white. If the light hits an object - a road, tree, house, anything really - the object absorbs some wavelengths. When an object absorbs all wavelengths to a great extent, it appears black. You can think of these phenomena in terms of the analogy: Light falling on an object is somewhat like rain falling on the ground. Different materials absorb different wavelengths of light. Examples of pigments are: heme, which gives blood a red color; melanin, which gives skin a brown color; and chlorophyll, which makes plants green. [ Back to Ask Science Theatre | Back to Ask Science Theatre Date Index ] Back to MSU Science Theatre Home Page