Chapter 5 Flashcards
Ions
atoms with a positive or negative electrical charge
Atomic number
the number of protons in an atom
Wavelength
the distance between adjacent peaks of a wave
Protons
Particles with positive electrical charge found in atomic nuclei, built from three quarks
Thermal radiation
the spectrum of radiation produced by an opaque object that depends only on the object’s temperature
Visible light
the light our eyes can see, ranging in wavelength from about 400 to 700 nm
Angular resolution
the smallest angular separation that two pointlike objects can have and still be seen as distinct points of light
Redshift
a Doppler shift in which spectral features are shifted to longer wavelengths, observed when an object is moving away from the observer
Intensity
a measure of the amount of energy coming from light of specific wavelength in the spectrum of an object
Transmission
(of light) the process in which light passes through matter without being absorbed
Light-collecting area
the area of the primary mirror or lens that collects light in a telescope
Frequency
the rate at which peaks of a wave pass by a point, measured in units of 1/s
Continuous spectrum
a spectrum (of light) that spans a broad range of wavelengths without interruption by emission or absorption lines
Electrons
fundamental particles with negative electric change
Ultraviolet
light with wavelengths that fall in the portion of the electromagnetic spectrum between visible light and x-rays
Thermal radiation spectrum
an object that produces a thermal radiation spectrum
Electromagnetic spectrum
the complete spectrum of light, including radio waves, infrared light, visible light, ultraviolet light, x-rays, and gamma rays
Doppler effect
the effect that shifts the wavelengths of spectral features in objects that are moving toward or away from the observer
Elements
a substance made from individual atoms of a particular atomic number
Speed of light
the speed at which light travels, which is about 300,000 km/s
Adaptive optics
a technique in which telescope mirrors flex rapidly to compensate for the bending of starlight caused by atmospheric turbulence
Reflecting telescope
a telescope that uses mirrors to focus light
emission lines
a bright band of single color, superimposed on a fainter or completely absent rainbow of light, occurring when light viewed through a diffraction element such as a prism shows an excess of photons at or near a specific wavelength
energy levels
broadly speaking, what can make matter move
Gamma rays
light with very short wavelengths- shorter than those of x-rays
Isotopes
forms of an element that have the same number of protons but different numbers of neutrons
X-rays
light with wavelengths that fall in the portion of the electromagnetic spectrum between ultraviolet light and gamma rays
Infrared
light with wavelengths that fall in the portion of the electromagnetic spectrum between radio waves and visible light
Electrical charge
a fundamental property of matter that is described by its amount and as either positive or negative
Blueshift
a Doppler shift in which spectral features are shifted to shorter wavelengths, observed when an object is moving toward the observer
Rest wavelengths
the wavelength of a spectral feature in the absence of any Doppler shift or gravitational redshift
Electromagnetic radiation
another name for light of all types, from radio waves through gamma rays
Interferometry
a telescopic technique in which two or more telescopes are used in tandem to produce much better angular resolution than the telescopes could achieve individually
Radio waves
light with very long wavelengths- longer than those of infrared light
Refracting telescope
a telescope that uses lense to focus light
Light pollution
human-made light that hinders astronomical observations
Emission
the process by which matter emits energy in the form of light
Microwaves
light with wavelengths in the range of micrometers to millimeters
Turbulence
rapid and random motion
Neutrons
particles with no electrical charge found in atomic nuclei, built from three quarks
Absorption
(of light) the process by which matter absorbs radiative energy
Electromagnetic wave
a synonym for light, which consists of waves of electric and magnetic fields
Atomic mass number
the combined number of protons and neutrons in an atom
Reflection/scattering
the process by which matter changes the direction of light
Strong force
one of the four fundamental forces; it is the force that holds atomic nuclei together
Molecules
technically, the smallest unit of a chemical element or compound
Photons
an individual particle of light, characterized by a wavelength and a frequency
