Material gravitationally captured from a normal
companion star, gas, nebula, or anything that
strays near a massive object that causes a
gravitational well (such as a black hole, neutron
star, etc.) will spiral down into or onto the
object. As it does, the material is heated by
compression (the internal friction) to
temperatures of up to 106K° centigrade,
or possibly more. Matter at such a temperature
will radiate strongly at the x-ray
wavelength.
Andromeda
Galaxy
The nearest spiral type galaxy similar to our own
Milky Way. The Andromeda Galaxy is 2 million light
years away (1.1749×1019 miles away.
That is 11,749,000,000,000,000,000 miles) so we
see it as it was 2 million years ago. Slightly
bigger than our own galaxy, Andromeda has about
300 billion stars, compared to our 100
billion.
Antimatter
The opposite of the basic unit of matter. Consists
of a nucleus (negatrons and neutrons) orbited by
positrons. The development of a theroy combining
the Special Theroy of relativity with Quantam
Mechanics led to the prediction of the existance
of antimatter, which has been proven since.
Antimatter behaves in almost all respects like
ordinary matter. In a striking demonstration of
the equivalence of restmass and energy, a particle
of matter and its antiparticle counterpart can be
simultaneously created from the pure energy of a
photon.
Black Holes
Any star over a value of 2-3 solar masses will
cause its remnant core to collapse indefinately,
becoming a black hole. The implosion takes perhaps
one ten-thousandth of a second (1/0.0001 of a
second). Perhaps the oddest thing about black
holes is what we call Time Dialation, where time
actually slows to a stop at the event horizon(depending upon
point of view).
Globular
Clusters
A dense symmetrical cluster of 105 to
106 stars. Generally found in the halo
of the galaxy. Globular clusters are generally
thought to represent remenants of the formation of
galaxies.
Parsec
1 parsec is the distance at which one Astronomical
Unit (the Earth orbit radius) subtends one
arcsecond. 1 pc = 3.086×1018cm = 3.26
light years.
Lagrangian
Points
Stable points in the orbit of a third body in a
binary system. (ex. A planet in a binary star
system. ex2. The third star ina trinary
system.)
Red Giant
Star
A star in which the helium core is fusing.
Subsequent to the Red Subgiant stage.
Chandracekhar
Mass
Maximum mass of a cold star that can support
itself by internal pressure against gravitational
collapse. Approx. 1.4 solar masses.
Event
Horizon
Surface of a black hole:
the boundry enclosing the region of spacetime that
cannot communicate with the external universe. A
one-way membrane accross which falling matteror
light is captured and can never on its own
escape.
Singularity
Region of infinate gravity, spacetime distortion,
and mass at the center of a black hole.
Inclination
Angle of tilt of the orbital plane with respect to
the fundamental plane.
Mesons
Elementary particles that decay within a short
lifetime.
Heliospere
The area of space around a star that is dominated
by the solar winds.
Absolute
Zero
Tempurature at which a gas has no thermal energy.
This is at 0ºK or at -459.69ºF.
Apogee
For an object in an elliptical orbit around
another object. The point in its orbit of greatest
enlongation.
Astronomical
Unit
The average distance between the sun and the
Earth; equal to 147,597,900 km.
Big Bang
The primordal explosion about 15 billion years ago
that launched the expansion of the Universe to its
present size.
Binary
Star
Two stars in orbit around their common center of
mass.
Cepheid
Variable
A giant pulsating star whos period of variation is
related to its absolute luminosity.
Corona
A mexican beer. Also the outermost portions of the
solar atmosphere reaching millions of kilometers
into space in the range of millions of
degrees.
Cosmic Microwave
Background
A relic radiation of the big bang. It now pervades
the entire Universe with a charactoristic temp of
2.7ºK.
Cosmic Ray
Mostly electrons, protons, and helium nuclei
moving through the galaxy at nearly the speed of
light.
Electron
An elementary particle with one unit of negatice
charge, and a mass of
9.1×10-20grams.
Fusion
Nuclear process that builds up heavier nuclei by
joining protons and neutrons with the release of
enormous amounts of energy.
Gamma Ray
Photons with the highest energies (in excess of 1
million electron volts) and highest frequencies
(above 1020Hz).
Gravity
Force of attraction that matter exerts on other
matter proportional to the product of the masses
of two objects and inversely proportional to the
square of their distance of
seperation.
Gravitational
Redshift
A decrease in the energy of a photon as it leaves
the surface of a massive object. The shift of the
wavelength to the red is proportional to the mass
of the object divided by the radius of its
surface.
Hertz
A unit of frequency equal to one cycle per
second.
Hubble's
Constant
The constant of proportionality that relates to
the velocities of recession of galaxies to their
distance.
Inverse-Square
Law
The apparent brightness of a source decreases in
proportion to the square of its distance. A star
100 light years away looks 1/4 as bright as the
same star at a distance of 50 light
years.
X-Rays
Photons of energies greater than that of gamma
rays with frquencies from 1017 to
1020 hertz.
Weak Force
A washed up Jedi Knight or one of the four
fundamental forces that acts only between certain
elementary particles in a nucleus.
Ultraviolet
Photons of higher frequencies than visible light
in the range of 1015 to 1016
hertz.
Strong Force
One of the four fundamental forces that is always
active and operates only at distances less than
10-13 centimeters to hold together the
nucleons inside an atomic nucleus.
Spectrum
The distribution of wavelength or frequency of the
number of photons emitted or absorbed by a
source.
Quark
Bar owner of DS9. Also an elementary particle that
comes in several forms. Three quarks make up a
proton or a neutron.
Plasma
An ionized gas in which the electrons that have
been removed are free to move about.
Photon
A quantam packet of electromagnetic raditation
with no mass and no electric charge, traveling at
the speed of light.
Neutrino
An elementary particle with zero or very small
rest mass and no electric charge that travels
close to the speed of light.
Microwaves
Radio photons with wavelengths between 1
millimeter and a few centimeters.
Acceleration
The rate at which the speed of an object is
changing.
Anthropic
Principle
We see the Universe as it is because if it were
different, we would not be here to observe
it.
Atom
The basic unit of matter. Consisting of a nucleus
(protons and neutrons) orbited by
electrons.
The Law of
Conservation of Energy
The law of science that states that energy (or its
equivilent in mass) can neither be created or
destroyed.
Coordinates
Numbers that specify the position of an object in
space and time.
