Explaining why the universe can be transparent
Two papers published by an assistant professor at the University of California, Riverside and several collaborators explain why the universe has enough energy to become transparent.
Two papers published by an assistant professor at the University of California, Riverside and several collaborators explain why the universe has enough energy to become transparent.
Astronomy
Sep 12, 2016
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1549
(PhysOrg.com) -- “For the first time, fields of study relating both to cold atoms and to the nanoscale have intersected,” Lene Vestergaard Hau tells PhysOrg.com. “Even though both have been active areas of research, ...
Aero/Astro engineer Ken Hara is developing computer models to help make a little-known, but widely-used thruster engine more suitable for long-distance missions.
Space Exploration
Feb 21, 2020
112
734
(PhysOrg.com) -- At very cold temperatures, in the absence of light, a photomultiplier will spontaneously emit single electrons. The phenomenon, which is called "cryogenic electron emission," was first observed nearly 50 ...
A study led by researchers from the U.S. Department of Energy's (DOE) SLAC National Accelerator Laboratory and the University of California, Los Angeles has demonstrated a new, efficient way to accelerate positrons, the antimatter ...
Plasma Physics
Aug 26, 2015
3
4267
The most luminous galaxy in the Universe - a so-called obscured quasar 12.4 billion light-years away - is so violently turbulent that it may eventually jettison its entire supply of star-forming gas, according to new observations ...
Astronomy
Jan 15, 2016
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1187
Lightning is a fascinating but dangerous atmospheric phenomenon. New research reveals that brief bursts of intense laser light can redirect these high-power electrical discharges.
General Physics
Mar 13, 2012
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An international team of scientists, including a University of York researcher, has carried out ground-breaking experiments to investigate the atomic structure of astatine (Z=85), the rarest naturally occurring element on ...
General Physics
May 14, 2013
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1
(Phys.org)—A team of researchers with member affiliations from across the globe has succeeded in conducting a measurement of the first ionization potential of lawrencium. In their paper published in the journal Nature, ...
(PhysOrg.com) -- NASA's Phoenix lander revealed water ice mere inches beneath the martian surface, and chemical evidence from the landing site strongly hints that the region is habitable. But learning whether there is life ...
Space Exploration
Jun 8, 2010
3
0
Ionization is the process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions. This is often confused with dissociation. A substance may dissociate without necessarily producing ions. As an example, the molecules of table sugar dissociate in water (sugar is dissolved) but exist as intact neutral entities. Another subtle event is the dissociation of sodium chloride (table salt) into sodium and chlorine ions. Although it may seem as a case of ionization, in reality the ions already exist within the crystal lattice. When salt is dissociated, its constituent ions are simply surrounded by water molecules and their effects are visible (e.g. the solution becomes electrolytic). However, no transfer or displacement of electrons occurs whatsoever. Actually, the chemical synthesis of salt involves ionization.
The process of ionization works slightly differently depending on whether an ion with a positive or a negative electric charge is being produced. A positively charged ion is produced when an electron bonded to an atom (or molecule) absorbs the proper amount of energy to escape from the electric potential barrier that originally confined it, thus breaking the bond and freeing it to move. The amount of energy required is called the ionization energy. A negatively charged ion is produced when a free electron collides with an atom and is subsequently caught inside the electric potential barrier, releasing any excess energy.
In general, ionization can be broken down into two types: sequential ionization and non-sequential ionization. In classical physics, only sequential ionization can take place; refer to the Classical ionization section for more information. Non-sequential ionization violates several laws of classical physics; refer to the Quantum ionization section.
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