Concepts and Definitions featured in A Short History of Nearly Everything
THE SCIENTIFIC METHOD – a four-step process developed by Descartes that includes, in this order: Observation, Making a Hypothesis, testing the Hypothesis, creating a Theory.
SINGULARITY – an infinitely dense point in space
THE BIG BANG - the scientific theory of how the universe emerged from a tremendously dense and hot state about 13.7 billion years ago.
COSMOLOGY - the branch of physics and astrophysics that deals with the study of the physical origins of the Universe and the nature of the Universe on its very largest scales.
INFLATION THEORY - first proposed by Alan Guth in 1981, the idea that that the early universe passed through a phase of extreme expansion.
SOLAR SYSTEM - the stellar system comprising the Sun and the celestial objects gravitationally bound to it: the eight planets, their 162 known moons, three currently identified dwarf planets and their four known moons, and thousands of small bodies that include asteroids, meteoroids, comets, and interplanetary dust.
OORT CLOUD – a spherical cloud of comets situated at the edge of our solar system, believed to be the source of most or all comets entering the inner solar system.
COMET - a small body in the solar system that orbits the Sun
ORBIT - the path that an object makes around another object while under the influence of a source of a force, such as gravity.
ELLIPSE – a mathematical description of space, also the orbits along which the planets travel around the Sun.
LIGHT SPEED – how fast light moves in a vacuum - approximately 186,282.397 miles per second.
LIGHT YEAR – how much distance light travels in a year – approximately 5,878,482,164,161 miles.
NEWTON’S LAW OF GRAVITY - states that: every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
- F is the magnitude of the gravitational force between the two point masses
- G is the gravitational constant
- m1 is the mass of the first point mass
- m2 is the mass of the second point mass
- r is the distance between the two point masses
URANIUM - a chemical element in the periodic table that has the symbol U and atomic number 92. Heavy, silvery-white, metallic, naturally radioactive.
RADIOACTIVITY – Discovered by Henri Becquerel, Marie and Pierre Curie. A set of various processes by which an unstable nucleus in an atom emit subatomic particles and energy.
NOBEL PRIZES - prizes instituted by the will of Alfred Nobel, awarded to people who have done outstanding research, invented groundbreaking techniques or equipment, or made outstanding contributions to society. Awarded in science as well as arts and activism.
QUANTUM THEORY – a theory in physics that energy (light included) comes in packets called quanta. First proposed by Max Plank. The theory is applied to many other theories in the sciences.
PHOTON – particle responsible for light
PHOTOELECTRIC EFFECT – Nobel Prize-winning idea by Einstein that the emission of electrons from matter upon the absorption of electromagnetic radiation, such as ultraviolet radiation or x-rays.
BROWNIAN MOTION - The physical phenomenon that minute particles, immersed in a fluid, move about randomly; made famous by Einstein’s 1905 paper on the subject.
ATOM - he smallest possible particle of a chemical element that retains its chemical properties. Made of protons, neutrons, and electrons.
MASS – a property of a physical object that quantifies the amount of matter and energy it is equivalent to.
MATTER - the substance of which physical objects are composed. Different from mass in that matter does not include energy or other forces.
SPACETIME - model that combines three-dimensional space and one-dimensional time into a single construct.
EINSTEIN’S GRAVITY – As part of his General Theory of Relativity, Einstein proposed that spacetime is curved by the presence of matter, and that objects that are gravitating to these objects are following bends and dips in spacetime.
SPECIAL THEORY OF RELATIVITY – proposed in 1905 by Albert Einstein saying that all observers will always measure the speed of light to be the same no matter how fast they are going. It overthrew Newton’s theories of absolute space and time. It does not deal with gravity.
GENERAL THEORY OF RELATIVITY - theory of gravity published by Albert Einstein in 1915 saying that gravity is not due to a force but rather is a manifestation of curved spacetime.
DIMENSIONS – a measurement required to define the characteristics of an object—like length, width, and height. Our universe has 3 dimensions (up-down, left-right, backwards-forwards), and 1 dimension of time.
SUPERSTRING THEORY - an attempt to explain all of the particles and fundamental forces of nature in one theory by modeling them as vibrations of tiny strings.
THEORY OF EVOLUTION - a theory proposed in its fullest form first by Charles Darwin. The theory discusses a way that life on Earth developed from a single one-celled organism through natural selection. Darwin published his book, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, in 1859.
NATURAL SELECTION - he process by which individual organisms with favorable traits are more likely to survive and reproduce than those with unfavorable traits.
ADAPTATION - an organism that developed traits to help it succeed in its habitat.
GENES - the units of heredity in living organisms, The word "gene" is also used in common speech to refer to the inheritance of a trait.
AUSTRALOPITHECINE - a group of extinct hominids that are closely related to humans and were widespread throughout Eastern and Southern Africa as early as 4.4 to as late as 1.7 million years ago
HOMO HABILIS - a species of hominid, which lived from approximately 2.5 million to 1.8 million years ago.
HOMO SAPIENS - (Latin for "wise man") the scientific name for human beings.
PROXIMA CENTAURI - this red dwarf star, part of the Alpha Centauri star system, is the nearest star to the Sun.
