Note: This is a 360° Video — press and hold to explore it!
Nuclear Energy Science Tracer Bullet (Library of Congress)
Nuclear Power (Wolfram Alpha)
These are organized by a classification scheme developed exclusively for Cosma. More…
CODATA Internationally recommended values of the Fundamental Physical Constants, Atomic and Nuclear (NIST Reference on Constants, Units and Uncertainty)
Radiation, Radioactivity & Radiobiology (Martindale’s Reference Desk)
atom : the smallest particle of an element that can exist either alone or in combination — Webster
Atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small; typical sizes are around 100 picometers (a ten-billionth of a meter, in the short scale).
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and typically a similar number of neutrons. Protons and neutrons are called nucleons. More than 99.94% of an atom’s mass is in the nucleus. The protons have a positive electric charge, the electrons have a negative electric charge, and the neutrons have no electric charge. If the number of protons and electrons are equal, that atom is electrically neutral. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively, and it is called an ion.
The electrons of an atom are attracted to the protons in an atomic nucleus by this electromagnetic force. The protons and neutrons in the nucleus are attracted to each other by a different force, the nuclear force, which is usually stronger than the electromagnetic force repelling the positively charged protons from one another. Under certain circumstances, the repelling electromagnetic force becomes stronger than the nuclear force, and nucleons can be ejected from the nucleus, leaving behind a different element: nuclear decay resulting in nuclear transmutation.
The number of protons in the nucleus defines to what chemical element the atom belongs: for example, all copper atoms contain 29 protons. The number of neutrons defines the isotope of the element. The number of electrons influences the magnetic properties of an atom. Atoms can attach to one or more other atoms by chemical bonds to form chemical compounds such as molecules. The ability of atoms to associate and dissociate is responsible for most of the physical changes observed in nature and is the subject of the discipline of chemistry. — Wikipedia
Atomic Physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. It is primarily concerned with the arrangement of electrons around the nucleus and the processes by which these arrangements change.
The term atomic physics can be associated with nuclear power and nuclear weapons, due to the synonymous use of atomic and nuclear in standard English. Physicists distinguish between atomic physics — which deals with the atom as a system consisting of a nucleus and electrons — and nuclear physics, which considers atomic nuclei alone. — Wikipedia
Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions. Other forms of nuclear matter are also studied. Nuclear physics should not be confused with atomic physics, which studies the atom as a whole, including its electrons. — Wikipedia
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
Merging neutron stars: How cosmic events give...
on February 14, 2019 at 12:24 pm
The opportunity to measure the gravitational waves of two merging neutron stars could offer answers to some of the fundamental questions about the structure of matter. At the extremely high temperatures and densities in the merger, scientists have conjectured a phase transition in which neutrons dissolve into their constituent quarks and gluons. In the current issue of Physical Review Letters, two international research groups report on their calculations of what the signature of such a phase […]
North Korea exploring sanctions-proof energy...
on February 14, 2019 at 8:14 am
Power-strapped North Korea is exploring two ambitious alternative energy sources—tidal power and coal-based synthetic fuels—that could greatly improve living standards and reduce its reliance on oil imports and vulnerability to sanctions. […]
Engineers develop room temperature,...
on February 11, 2019 at 8:06 pm
Quantum computers promise to be a revolutionary technology because their elementary building blocks, qubits, can hold more information than the binary, 0-or-1 bits of classical computers. But to harness this capability, hardware must be developed that can access, measure and manipulate individual quantum states. […]
Researchers examine puzzling sizes of extremely...
on February 11, 2019 at 8:05 pm
Michigan State University researchers have measured for the first time the nuclei of three proton-rich calcium isotopes, according to a new paper published in Nature Physics. […]
To save the Earth someday, team builds spacecraft...
on February 8, 2019 at 2:40 pm
A team of scientists, astronomers and engineers meets weekly in a conference room on a Howard County, Md., research campus and plans to save the world. […]