Astronomy At Play in the Cosmos Ch. 4 – Flashcards
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matter
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any substance made up of particles that mass that occupies space
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spectrograph
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a device for separating light from a source into its component wavelengths and measuring the energy at each wavelength
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wavelength
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the distance between successive peaks to troughs of a wave
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frequency
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the number of peaks or troughs of a wave that pass a point in space in a single second
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amplitude
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a measure of the wave's strength
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electromagnetic radiation
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oscillating electric and magnetic fields traveling through space
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visible light
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the form of light to which the human eye responds ranging from 400 to 700 nm
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electromagnetic spectrum
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the full range of electromagnetic radiation at different wavelengths running from gamma rays (very short) to radio waves (very long)
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radio wave
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an electromagnetic wave with a wavelength great than 0.1 meter
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microwave
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the shortest wavelength radio wave, with a wavelength of 1 millimeter to about 0.1 meter
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infrared wave
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an electromagnet wave with a wavelength of 700 nanometers to 1 millimeter, just longer than those of visible light
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ultraviolet wave
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an electromagnetic wave with a wavelength of 10-400 nanometers, just short of visible light
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x-ray
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an electromagnetic wave with a wavelength between 10^-11 and 10^-8 meter
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gamma ray
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a high energy electromagnetic wave with a wavelength leas than 10^-11 meter
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refraction
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the bending of light as it passes between two media, such as water and air
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spectrum (pl. spectra)
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the distribution of light intensity versus wavelength (or frequency)
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emission line
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a bright line at a particular wavelength in a spectrum. specific patterns of emission lines indicate the presence of a specific elect in the source
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absorption line
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a dark line in a continuous spectrum. specific patterns of absorption lines in a spectrum indicate a specific element in the soutce
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energy
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the ability to preform work. energy comes in many forms, such as kinetic, thermal, gravitational, and electromagnetic
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kinetic energy
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energy that is due to an object's bulk motion
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gravitational potential energy
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energy that an object possesses because of its position in a gravitational field
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thermal ebergy
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energy that is due to random motions pf atoms
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blackbody radiation
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electromagnetic radiation from a dense, opaque body, whose spectrum depends only on the temperature of the body
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photon
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a particle of light
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Wein's Law
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the mathematical relation between a blackbody's temperature and the wavelength at which it radiates with peak intensity
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luminosity
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the total energy output per time of light source
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Stefan-Boltzmann Law
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the mathematical relationship between a blackbody's luminosity and its surface area and temperature
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nebula
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an interstellar cloud of dust, hydrogen, helium, and other ionized gasses
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quantum mechanics or quantum physics
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a branch of physics dealing with physical phenomena at the level of molecular, atomic, and subatomic levels
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nucleus
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the dense region at the center of an atom consisting of protons and neutrons
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neutron
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a subatomic particle with no electric charge within an atomic nucleus
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proton
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a subatomic particle with a positive electric charge
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electron
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a subatomic particle with a negative electric charge
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Bohr atom
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a model of the atom, devised by Niels Bohr, in which electrons in discrete orbits surround positively charged nucleus. electron "jumps" between the discrete orbits determine omission or absorption of light
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emission
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the release of a photon of a specific wavelength when an electron jumps from a higher to lower energy level
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ground state
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the lowest energy state within an atom
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excited state
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any energy state within an atom that is higher than the ground state.
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absorption
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the capture of a photon of a specific wavelength, causing an electron to jump from a lower to a higher energy level
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energy level
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any one of the certain discrete values of orbital energy possible for an atom
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Lymann series
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emission or absorption lines of the hydrogen atom as an electron moves between the ground state and excited states
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Balmer Series
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emission or absorption lines of the hydrogen atom as an electron moves between the first excited state and higher energy states
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Doppler shift
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a change in wavelength that results because either a wave source or an observer moves relative to the other
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redshift
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an increase in the wavelength of light that results when the source of the light moves away from the observer or the observer moves away from the light source
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blueshift
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a decrese in the wavelength of light the results when the source of light moves towards the observer or the observer moves closer to the light source.
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standard candle
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an object with known luminosity that can be used to determine distance
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aperature
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the diameter of a telescope's main light-collecting lens or mirror
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angular resolutoin
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a measure of the ability of a telescope to separate or distinguish features in a distant object
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magnification
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the ability of a telescope to enlarge appearances of an image
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refractor
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an optical telescope that uses a lens to collect light and form an image
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objective
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in a refarator telescope, the largest lens that gathers light from the object being observed and focuses the light rays to form an image
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eyepeice
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the small lens of a telescope through which the observer looks through
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chromatic aberration
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the failure of a lens to focus all colors to the same point
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reflector
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an optical telescope that uses curved mirrors to collect light and form an image
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transmission
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the passing of light through matter without being absorbed
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opacity
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the degree to which light being absorbed when passing through a material
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turbulence
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the random jostling motion of moving air
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adaptive optics
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a telescope technology in which mirror segments are rapidly adjusted to account for atmospheric turbulence and produce higher resolution images
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interferometry
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the technique of combining the signal from many smaller telescopes to achieve the resolving power of a larger one
