Connecting Quarks with the Cosmos Eleven Science Questions for the New Century (2003) / Chapter Skim
Currently Skimming:
Appendix D: Glossary and Acronyms
Appendix D: Glossary and Acronyms
Pages 191-206
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 191... ...
The distribution of galaxies in space is not uniform, whereas the intensity of the cosmic background radiation from the big bang is highly uniform in all directions i.e., it is almost isotropic. Astronomers are using sensitive telescopes to study the small anisotropies in the cosmic background radiation that should be present given the nonuniform distribution of galaxies.
|
From page 192... ...
The boundary of this region is called the black hole's event horizon (q.v.~. Black holes can form when a massive star undergoes gravitational collapse (q.v.~.
|
From page 193... ...
compact object: compact objects are the remnants of stars that have burned all of their nuclear fuel, forming white dwarfs, neutron stars, or black holes. The extreme gravitational fields near the stars make them valuable as physical laboratories for studying the gravitational force itself.
|
From page 194... ...
When used by particle physicists, it describes the lowest energy state of a system when it is not empty, but rather is filled with a particular nonzero value for some field. cosmic microwave background (CMB)
|
From page 195... ...
, to visible and ultraviolet light; and extremely short wavelengths, to x rays and gamma rays. Most astronomical observations measure some form of electromagnetic radiation.
|
From page 196... ...
Department of Energy's Fermi National Accelerator Laboratory, located in Batavia, Illinois. fermion: particles with the property that only one can occupy a quantum state (the Pauli exclusion principle)
|
From page 197... ...
exerting a gravitational pull on the surrounding galaxies, including the Milky Way, proposed to explain the observed movement of these galaxies toward the Hydra-Centaurus superclusters in the southern sky with velocities significantly different from those predicted by Hubble law expansion. hadron: a strongly interacting particle such as a proton or neutron.
|
From page 198... ...
The energy associated with the quarks and/or gluons ultimately manifests itself in streams of elementary particles which can be detected. jet, astrophysical: stream of fast-moving material flowing outward from an object such as a young star or a massive central black hole in a galaxy.
|
From page 199... ...
magnetars: neutron stars with the largest known magnetic fields in the universe. MAP satellite: NASA's Microwave Anisotropy Probe, launched in June 2001 designed to accurately map the microwave sky with an angular resolution of 0.2 degrees.
|
From page 200... ...
Phase transitions can occur by altering such variables as temperature and pressure. photon: quantum of electromagnetic energy; a unique massless particle that carries the electromagnetic force.
|
From page 201... ...
The sweeping action of the beam causes the object to pulse regularly when viewed by an observer, just as with a lighthouse. QCD: quantum chromodynamics, the theory that describes the strong force among quarks in a manner analogous to the description of the electromagnetic force by quantum electrodynamics.
|
From page 202... ...
Schwarzschild radius: the location of the "surface" of a black hole, from whose interior it is impossible to escape. shock waves: a very narrow region of high pressure and temperature formed in a fluid when the fluid flows supersonically over a stationary object or when a projectile flying supersonically passes through a stationary fluid.
|
From page 203... ...
It includes three generations of quarks and leptons, the electroweak theory of weak and electromagnetic forces, and the quantum chromodynamic theory of the strong force. It does not include answers to some basic questions such as how to unify electroweak forces with the strong or gravitational forces.
|
From page 204... ...
synchrotron radiation: electromagnetic radiation that is emitted by charged particles moving at relativistic speeds in circular orbits in a magnetic field. Much of the microwave radiation from celestial radio sources outside the galaxy is believed to originate from electrons moving in curved paths in celestial magnetic fields; it is also called synchrotron radiation.
|
From page 205... ...
A perfect vacuum would contain no atoms or molecules but is unobtainable, as all the materials that surround such a space have a finite vapor pressure and give off atoms into the void. vacuum energy (sometimes called "Einstein's cosmological constantly: quantum physics requires "empty space" to be filled with particles and antiparticles being continually created and annihilated.
|
From page 206... ...
White dwarfs are typically composed primarily of carbon, have about the radius of Earth, and do not significantly evolve further. x-ray binary: a double star in which one of the stars accretes matter from its binary companion (q.v.)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.