Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
167 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
Angstrom Ǻ
|
A unit of distance equaling 1-billionth of a meter (10-9); commonly used to measure wavelength (λ)
|
|
|
|
Angular diameter
|
The angle formed by lines extending from the observer to opposite sides of an object
|
|
|
|
Angular distance
|
The angle formed by lines extending from the observer to two locations
|
|
|
|
Apelion
|
Orbital point farthest from the Sun
|
|
|
|
AU
|
Astronomical unit: average distance from Earth to the Sun or approximately 1.5 x 10^8 km or 93 x 10^6miles
|
|
|
|
celestial equator
|
projection of the Earth's equator on the celestial sphere
|
|
|
|
Chromosphere
|
Bright gases just above the photosphere of the sun
|
|
|
|
closed orbit
|
an orbit that returns to the same starting point over and an over- either circular or elliptical
|
|
|
|
Constellation
|
One of the stellar patterns identified by name
|
|
|
|
Corona
|
The faint outer atmosphere of the sun, composed of low-density, high temperature gas
|
|
|
|
Diamond-ring effect
|
During total solar eclipse, the momentary appearance of a spot of photosphere at the edge of the moon producing a brilliant glare set in the silvery ring of the corona
|
|
|
|
ecliptic
|
apparent pathway of the Sun against the stars as seen from Earth - a projection of the Earth's orbit
|
|
|
|
ellipse
|
A closed curve around two points called foci such that the total distance from one focus to the curve and back to the other focus remains constant
|
|
|
|
epicycle
|
the small circle followed by a planet in the Ptolemaic theory. The center of the epicycle follows a larger circle (derant) around the Earth
|
|
|
|
equinox
|
day with equal amounts of sunlight / darkness
|
|
|
|
Evening star
|
any planet first visible in the evening (sunset) sky
|
|
|
|
eyepiece
|
a short forcal length lens used to enlarge the image in a telescope; lens nearest the eye
|
|
|
|
false-color image
|
A representation of graphical data with added or enhanced color added to reveal detail
|
|
|
|
Geocentric Universe
|
A model universe with Earth at the center. -i.e. Ptolemaic Universe
|
|
|
|
How is resolution determined?
|
wavelength / diameter of telescope
|
|
|
|
Intensity
|
A measure of the light energy from a star that hits one square meter in one second (m2/s)
|
|
|
|
Kepler's 2nd law
|
Speed of the planets varies depending on it's orbit; it covers equal areas in equal intervals of time
|
|
|
|
ly
|
Light year: a unit of distance that light travels in one year- approximately 10^13 km or 63,000 AU
|
|
|
|
Mars: distance / orbital period
|
1.5 AU from the Sun, Orbital period approximately 2 years
|
|
|
|
Minute of arc
|
An angular measure: 1/60th of a degree
|
|
|
|
Morning star
|
any planet visible shortly before sunrise
|
|
|
|
nanometer (nm)
|
|
|
|
|
Perihelion
|
Orbital point of closest approach to the sun
|
|
|
|
Photon
|
A quantum of electromagnetic energy; carries an amount of energy that depends inversely on its wavelength
|
|
|
|
Photosphere
|
The bright visible surface of the sun
|
|
|
|
Second of arc
|
An angular measure: 1/60th of a minute of arc
|
|
|
|
solar eclipse
|
An event that occurs when the moon passes directly between the Earth and the Sun, blocking our view of the sun
|
|
|
|
Spring tide
|
Ocean tide of high amplitude that occurs at full and new moon; at this point the moon is aligned with the Earth and Sun so the sun's gravity works with the moon'sand amplifies the tide
|
|
|
|
synodic period
|
The time a solar system body takes to orbit the sun once and return to the same orbital relationship with the Earth
|
|
|
|
Vernal equinox
|
The place on the celestial sphere where the sun crosses the celestial equator moving northward
|
March 20; Spring begins
|
|
|
Zodiac
|
band around the sky extending 9 degrees above and below the ecliptic
|
|
|
|
λ
|
symbol for wavelength
|
|
|
|
Geosynchronous satellite
|
A satellite that orbits eastward around the Earth with a period of 24 hours and remains in the same spot above the Earth's surface
|
|
|
|
center of mass
|
The balance point of a body or system of masses; the point about which a body or system of masses rotates in the absence of external forces
|
|
|
|
refracting telescope
|
A telescope that forms images by bending (refracting) light with a lens
|
|
|
|
Milankovitch hypothesis
|
Suggestions that Earth's climate is determined by slow periodic changes in the shape of it's orbit, the angle of it's axis and percession
|
|
|
|
reflecting telescope
|
A telescope that uses a concave mirror to focus light into an image
|
|
|
|
chromatic aberation
|
A distortion ofund in refracting telescopes because lenses focus different colors at slightly different distances. Consequently images are surrounded by color finges
|
|
|
|
achromatic lens
|
A telescope lens composed of 2 lenses ground from different kinds of glass and designed to bring 2 selected colors to the same focus and correct for chromatic abberation
|
|
|
|
light-gathering power
|
the ability of a telescope to collect light - proportional to the area of the telescope's objective lens or mirror
|
|
|
|
revolving power
|
The ability of a telescope to reveal fine detail - depends on the diameter of the telescope's objective
|
|
|
|
1 mile = ?km
|
1 mile = 1.609 km
|
|
|
|
diffaction fringe
|
blurred fringe surround any image, caused by the wave properties of light
|
|
|
|
north celestial pole
|
point on the celestial sphere directly above the Earth's north pole
|
|
|
|
Seeing
|
Atmospheric conditions on a given night
|
|
|
|
Magnifying power
|
The ability of a telescope to make an image larger
|
|
|
|
light pollution
|
The illumination of the night sky by wasted light from cities and outdoor lighting which prevents the observation of faint objects
|
|
|
|
prime focus
|
The point at which the objective mirror forms an image in a reflecting telescope
|
|
|
|
secondary mirror
|
In a reflecting telescope a mirror that directs the light from the primary mirror to a focal point
|
|
|
|
Cassegrain focus
|
The optical design in which the secondary mirror reflects light back down thruough a tube that lies in a hole in the center of the objective mirror
|
|
|
|
Newton's Law of Gravity- equation
|
F = (-G) * Mm/r² Mm: masses of 2 orbiting objects r²: distance between centers of objects -G: gravitational constant F: force of gravity between 2 objects
|
|
|
|
Umbra
|
The region of shadow that is totally shaded
|
|
|
|
Penumbra
|
The portion of a shadow that is only partially shaded
|
|
|
|
Newtonian focus
|
The optical design in which a diagonal mirror reflects light out the side of the telescope tube for easier access
|
|
|
|
Schmidt-Cassegrain focus
|
The optical design that uses a thin corrector plate at the entrance to the telescope tube - allows wide angle viewing
|
|
|
|
Sidereal drive
|
The motor and gears on a telescope that turn it westward to keep it pointed at a star
|
|
|
|
escape velocity
|
The initial velocity an object needs to escape from the surface of a celestial body
|
|
|
|
Asterism
|
A named grouping of stars that is not one of the recognized constellations
|
|
|
|
Node
|
The points where an object's orbit passes through the plane of the Earth's orbit
|
|
|
|
Prominence
|
Eruption on the solar surface; most visible during the total solar eclipse
|
|
|
|
Summer solstice
|
The point on the celestial sphere where the sun is at it's most northernly point
|
|
|
|
Objective lens or mirror
|
In a refracting telescope, the long-focal length lens that forms an image of the object viewed; lens closest to the object. In a reflecting telescope, the principal mirror that forms an image of the object viewed.
|
|
|
|
Primary lens or mirror
|
The largest lens or mirror in the telescope
|
|
|
|
Nadir
|
Point on the celestial sphere directly below the observer
|
|
|
|
wave length
|
The distance between successive peaks or troughs of a wave; represented by λ
|
|
|
|
electromagnetic radiation
|
Changing electric and magnetic fields that travel through space at the speed of light and transfer energy from one place to another
|
example: Lightwaves, radio waves
|
|
|
zenith
|
Point on the celestial sphere directly above the observer
|
|
|
|
circular velocity
|
The velocity an object needs to stay in orbit around another object
|
|
|
|
Neap tide
|
Ocean tide of low amplitude occuring in the 1st and 3rd quarters of the moon. Moon and sun's gravity work against each other, decreasing the size of the tides
|
|
|
|
Natural law
|
A theory that is almost universally accepted as true
|
|
|
|
Group 2A
|
Alkaline Earth metals: +2 charge
|
|
|
|
Paradigm
|
A commonly acceptd set of scientific ideas and assumptions
|
|
|
|
South celestial pole
|
Point on the celestial sphere directly above the Earth's south pole
|
|
|
|
This planet is slightly bigger than the moon and .39 AU from the Sun
|
Mercury
|
|
|
|
Atmospheric window
|
Wave length region in which our atmosphere is transparent - @ visual, infrared and radio wavelengths
|
|
|
|
Focal length
|
The focal length of a lens is the distance from the lens to the point where it focuses parallel rays (light rays from very great distances) of light
|
|
|
|
Beta particle
|
high speed electron
|
|
|
|
Mass
|
The measure of the amount of matter making up an object
|
|
|
|
Retrograde motion
|
The apparent backward (westward) motion of planetsas seen against the background of stars
|
|
|
|
Weight
|
Measure of gravitational forces acting on an object
|
|
|
|
achromatic lens
|
A telescope lens composed of two lenses ground from different kinds of glass and designed to bring two selected colors to the same focus and correct for chromatic abberation
|
|
|
|
Speed of light
|
300,000 km/s
|
|
|
|
Open orbit
|
An orbit that carries an object away, never to return to it's starting point
|
|
|
|
Horizon
|
Circular boundary between the sky and the earth
|
|
|
|
How to determine magnitude / intensity
|
Mb-Mb = 2.5 lgo (Ia/Ib) or Ia/Ib = 2.512^Mb-Ma
|
|
|
|
Morning start
|
any planet visible in the sky just before sunrise
|
|
|
|
Sidereal period
|
The time a celestial body takes to turn once on its axis or revolve once in its orbit relative to the stars
|
|
|
|
Celestial sphere
|
An imaginary sphere of very large radius surrounding the Earth and to which the planets, stars, sun and moon SEEM attached
|
|
|
|
Magnitude scale
|
astronomical brightness cale; the larger the number, the fainter the star
|
|
|
|
Scientific notation
|
System of recording very large or very small numbers by using powers of 10
|
|
|
|
Solar system
|
The sun, its planets, asteroids, comets and so on
|
|
|
|
Planet
|
A small nonluminous body that shines by reflected light
|
|
|
|
Star
|
A globe of gas held together by its own gravity and supported by the internal pressures of it's hot gases which genreate energy by nuclear fusion
|
|
|
|
Astronomical unit (AU)
|
The average distance from Earth to the Sun; 1.5 x 10^8 or 93 x 10^6
|
|
|
|
Circular velocity equation
|
Vc = sqrt of GM/r
Vc= velocity G=gravitational contant 6.67 x 10^-11 m^3/s^2kg m: mass of central body r: radius of the orbit in meters |
|
|
|
Comparison spectrum
|
a spectrum of known spectral lines used to identify unknown wavelengths in an objects spectrum
|
|
|
|
Adaptive optics
|
a computer controlled optical system used to partially correct for seeing in an astronomical telescope
|
|
|
|
Active optics
|
Thin telescope mirrors that are controlled by computers to maintain proper shape as the telescope moves
|
|
|
|
Density
|
Mass/Volume
|
|
|
|
Interferometry
|
The observing technique in which separate telescopes are combined to produce a virtual telescope with a resolution of a telescope of a much larger diameter
|
|
|
|
Alt-azimuth mounting
|
a telescope mounting that allows the telescope to move in altitude (perpendicular to the horizon) and azimuth (parallel to the horizon)
|
|
|
|
Equant
|
In Ptolemaic theory, the point off the center in the deferent from which the center of the epicycle appears to move uniformly
|
|
|
|
Uniform circular motion
|
The classic belief that the perfec heavens could only move by the combination of uniform motion along circular orbits
|
|
|
|
Winter solstice
|
Point on the celestial sphere where the sun is farthest south
|
|
|
|
Evening star
|
Any planet visible in the sky just after sunset
|
|
|
|
Precession
|
The slow change in the direction of Earth's axis of rotation
One cycle takes approximately 26,000 years |
|
|
|
Parallax
|
The apparent change in positoin of an object due to a change in the location of the observer
|
|
|
|
spectral line
|
A line a spectrum at a specific wavelength produced by the absorption or emission of light by certain atoms
|
|
|
|
nucleus
|
The central core of an atom containing protons and neutrons; carries a positive charge
|
|
|
|
proton
|
a positively charged atomic particle contained in the nucleus of an atom; sometimes refers to the nuceus of the hydrogen atom
|
|
|
|
neutron
|
an atomic particle with no charge and approximately the same mass as a proton
|
|
|
|
electron
|
low-mass atomic particle carrying a negative charge
|
|
|
|
Isotope
|
an atom that has the same number of protons but a different number of neutrons
|
|
|
|
Ionization
|
the process in which atoms gain or lose electrons
|
|
|
|
ion
|
an atom that has lost or gain electrons
|
|
|
|
molecule
|
two or more atoms bonded together
|
|
|
|
Coulomb forces
|
the electrostatic force of repulsion or attraction between charged bodies
|
|
|
|
Binding energy
|
the energy needed to pull an electron away from its atom
|
|
|
|
Quantum mechanics
|
the study of the behavoir of atoms and atomic particles
|
|
|
|
Permitted orbit
|
one of the energy levels in an atom that an electron may occupy
|
|
|
|
Energy level
|
one of the number of states an electron my occupy in an atom, depending on its binding energy
|
|
|
|
excited atom
|
an atom in which an electron has moved from a lower to a higher energy level
|
|
|
|
ground state
|
the lowest permitted electron energy level in an atom
|
|
|
|
heat
|
the flow of thermal energy
|
|
|
|
temperature
|
a measure of the agitation among the atoms and molecules of a material: aka the intensity of atomic motion
|
|
|
|
Kelvin temperature scale
|
a temperature scale using Celsius degrees and based on zero at absolute zero
|
|
|
|
absolute zero
|
the theoretical lowest possible temperature at which a material contains no extractable heat energy; established as zero onthe Kelvin temperature scale
|
|
|
|
black body radiation
|
radiation emitted by a hypothetical perfect radiator. The spectrum is continuous, and the wavelength of maximum emission depends on the body's temperature
|
|
|
|
Wavelength of maximum intensity
|
the wavelength at which a perfect radiator emits the maximum amount of energy. Depends only on the object's temperature
|
|
|
|
Joule
|
A unit of energy equivalent to the force of 1 newton acting over a distance of 1 meter: 1 joule per second equals 1 watt of power
|
|
|
|
continuous spectrum
|
a spectrum in which there are no absorption or emission lines
|
|
|
|
absorption spectrum
|
spectrum that contains absorption lines caused by photons being absorbed by atoms or molecules
|
|
|
|
emission spectrum
|
a spectrum containing emission lines
|
|
|
|
length of 1 light year (ly)
|
63, 000 AU
|
|
|
|
emission line
|
a bright line in a spectrum caused by the emissio of photons from atoms
|
|
|
|
spectrograph
|
a device that separates light by wavelengths to produce a spectrum - a fingerprint of the source of the light
|
|
|
|
absorption line
|
a dark line in a spectrum; is produced by the absence of photons absorbed by atoms or molecules
|
|
|
|
Kirchoff's laws
|
a set of laws that describe the absorption and emission of light by matter
|
|
|
|
transition
|
the movement of an electron from one atomic energy level to another
|
|
|
|
Lyman series
|
Spectral lines in the ultraviolet spectrum of hydrogen produced by transitions whose lowest energy level is the ground state
|
|
|
|
Balmer series
|
A series of spectral lines produced by hydrogen in the near-ultraviolet and visible parts of the spectrum
|
|
|
|
Paschen series
|
Spectral lines in the infrared spectrum of hydrogen produced by the transitions whose lowest energy level is third
|
|
|
|
spectral class or type
|
A star's positoin in the temperature classification OBAFGKM; is based on the appearance of the star's spectrum
|
|
|
|
Spectral sequence
|
the arrangement of spectral classes ranging from hot to cool
|
|
|
|
Celcius to Kelvin
|
K = C + 273.15
|
|
|
|
L dwarf
|
a main sequence star cooler than an M star
|
|
|
|
T dwarf
|
a very cool, low-mass star or brown dwarf located below the L stars on the main sequence
|
|
|
|
Doppler effect
|
the change in the wavelength of radiation due to the relative radial motion of source and observer
|
|
|
|
Blueshift
|
A Doppler shift twoard shorter wavelengths caused by a velocity of approach
|
|
|
|
Redshift
|
A Doppler shift toward longer wavelengths caused by a velocity of recession
|
|
|
|
radial velocity (Vr)
|
a component of an object's velocity directed away from or toward Earth
|
|
|
|
charged coupled device (CCD)`
|
an electronic device consisting of a large arrange of light-sensitive elements used to record very faint images
|
|
|
|
Absorption spectrum
|
Produced when radiation passes through a cooler gas: results in dark lines in a spectrum
|
|
|
|
Autumnal Equinox
|
The point on the celestial sphere where the sun crosses the celestial equator going southward.
Sept 22 Fall begins |
|
|
|
Ecliptic
|
The apparent path of the sun around the sky
|
|
|
|
Eccentricity
|
A number between 1 and 0 that describes the shape of an ellipse:
Distance of 1 focus to center of ellipse divided by semimajor axis In a circle: 0, while in an oval: close to 1 |
|
|
|
Saros cycle
|
An 18 year, 11.33 day period after which the pattern of lunar and solar eclipses repeats
|
|
|
|
Gamma particles
|
high energy light
|
|
|
|
Aphelion
|
Orbital point of greatest distance from the sun
|
|
|
|
Scientific model
|
a tentative description of a phenomenon for use as an aide to understanding
|
|
|
|
Sunspots
|
relatively dark spots on the sun that contain intense magnetic fields
|
|
|
|
Granulation
|
the fine structure of bright grains covering the sun's surface
|
|
