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Physical Realm
Physical Laws (Constants) Relativity
Matter Molecule, Atom (Periodic Table), Particle
Force Gravity, Electromagnetism (Light, Color)


These are organized by a classification scheme developed exclusively for Cosma. More…



relativity : a theory which is based on the two postulates (1) that the speed of light in a vacuum is constant and independent of the source or observer and (2) that the mathematical forms of the laws of physics are invariant in all inertial systems and which leads to the assertion of the equivalence of mass and energy and of change in mass, dimension, and time with increased velocity — called also special relativity, special theory of relativity — Webster

OneLook, Free Dictionary, Wiktionary, Urban Dictionary


Roget’s II (, Merriam-Webster Thesaurus, Visuwords


Relativity, generally refers to the theory of relativity usually encompasses two interrelated theories by Albert Einstein: special relativity and general relativity.

Special relativity applies to elementary particles and their interactions, describing all their physical phenomena except gravity.

General relativity explains the law of gravitation and its relation to other forces of nature. It applies to the cosmological and astrophysical realm, including astronomy.

The theory transformed theoretical physics and astronomy during the 20th century, superseding a 200-year-old theory of mechanics created primarily by Isaac Newton. It introduced concepts including spacetime as a unified entity of space and time, relativity of simultaneity, kinematic and gravitational time dilation, and length contraction.

In the field of physics, relativity improved the science of elementary particles and their fundamental interactions, along with ushering in the nuclear age. — Wikipedia

Encyclopædia Britannica

Relativity Theory (Eric Weisstein’s World of Physics, Wolfram Research)


What is relativity? Einstein’s mind-bending theory explained (Dan Falk, Mach, NBC News)
The Theory of Relativity (Ask an Astronomer, Cornell University)






The Collected Papers of Albert Einstein (California Institute of Technology)


WorldCat, Library of Congress, UPenn Online Books, Open Library




Special Relativity Course (Minute Physics)

Crash Course Physics (YouTube)

Einstein, Oppenheimer, Feynman: Physics in the 20th Century (MIT OCW Physics)
Introduction to Nuclear and Particle Physics (MIT OCW Physics)
Relativity (MIT OCW Physics)
OER Commons: Open Educational Resources


Science Daily,, NPR Archives









Albert Einstein News -- ScienceDaily Albert Einstein in the News. Research institutes have been testing Albert Einstein's theory of special relativity and general relativity. Was Albert Einstein right?

  • Lab-based dark energy experiment narrows search...
    on August 19, 2019 at 3:00 pm

    An experiment to test a popular theory of dark energy has found no evidence of new forces, placing strong constraints on related theories.

  • Supercomputer shows 'Chameleon Theory' could...
    on July 8, 2019 at 5:11 pm

    Supercomputer simulations of galaxies have shown that Einstein's theory of General Relativity might not be the only way to explain how gravity works or how galaxies form.

  • Researchers find quantum gravity has no symmetry
    on June 19, 2019 at 2:31 pm

    Using holography, researchers have found when gravity is combined with quantum mechanics, symmetry is not possible.

  • Development of a displacement sensor to measure...
    on May 17, 2019 at 3:51 pm

    One of the most unknown phenomena in modern physics is gravity. Its measurement and laws remain somewhat of an enigma. Researchers have revealed important information about a new aspect of the nature of gravity by probing the smallest mass-scale.

  • Testing the symmetry of space-time by means of...
    on March 13, 2019 at 6:33 pm

    According to Einstein the speed of light is always the same. But according to theoretical models of quantum gravitation, this uniformity of space-time does not apply to particles. Physicists have now tried to detect a change in the uniformity of space-time using two optical Ytterbium clocks. - latest science and technology news stories internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.

  • Students who plan to seek more education than...
    on August 20, 2019 at 2:50 pm

    When it comes to career success, it pays to aim for more education than what you need for the job you want.

  • Studying animal cognition in the wild
    on August 20, 2019 at 2:33 pm

    Different types of cognitive abilities can lead to a variety of knowledge that can help an animal to find, access, and guard food and mates. One approach to gain insight into the evolution of such cognitive abilities is by inferring cognitive performances from observed behaviours across closely related species and to compare them. By linking differences in cognitive performances with differences in current socio-ecological circumstances, hypotheses about the evolutionary pressures that […]

  • Researchers propose new holographic method to...
    on August 20, 2019 at 2:16 pm

    A research team from Osaka University, Nihon University and Chuo University has proposed a novel theoretical framework whose experiment could be performed in a laboratory to better understand the physics of black holes. This project can shed light on the fundamental laws that govern the cosmos on both unimaginably small and vastly large scales.

  • Statistics plot pollution to inform policy
    on August 20, 2019 at 2:09 pm

    The spatial variation in different air pollution components helps identify possible targets for pollution control.

  • All-in-one: New microbe degrades oil to gas
    on August 20, 2019 at 2:04 pm

    Crude oil and gas naturally escape from the seabed in many places known as "seeps." There, these hydrocarbons move up from source rocks through fractures and sediments toward the surface, where they leak out of the ground and sustain a diversity of densely populated habitats in the dark ocean. Alkanes are already degraded before they reach the sediment surface. Even deep down in the sediment, where no oxygen exists, it provides an important energy source for subsurface microorganisms, amongst […]