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47 terms

science ch 4 test

STUDY
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visible light
light you can see
elecromagnetic radiation
energy that can travel through space in the from of waves
wavelength
distance between the crest of one wave and the crest of the next wave
spectrum
range of different colors with different wavelengths that you can see if you shine white light through a prism
electromagnetic spectrum
radio waves, infrared radiation, visible light, ultraviolet radiation, x-rays, gamma rays
telescope
instrument that collects and focuses light and other forms of electromagnetic radiation
optical telescope
telescope that uses lenses or mirrors to collect and focus visible light
refracting telescope
uses convex lenses to gather and focus light
convex lens
piece of transparent glass, curved so that the middle is thicker than the edges
reflecting telescope
uses a curved mirror to collect and focus light
radio telescope
used to detect radio waves from objects in space
observatory
building that contains one or more telescopes
constellations
imaginary patterns of stars
star characteristics
color, temperature, size, compostition, brightness
spectograph
device that breaks light into colors and produces and image of the resulting spectrum
size and temperature
what the brightness of a star depends on
apparent brightness
a star's brightness as seen from earth
absolute brightness
brightness the star would have if it were at a standard distance from Earth
light year
the way scientists use to measure distances between stars
parallax
apparent change in position of an object when you look at it from different places
H-R diagram
diagram used to classify stars and to understand how stars change over time
main sequence
diagonal area in H-R diagram
protostar
earliest stage of a star's life
nebula
large cloud of gas and dust that spread out in an immense volume
mass
depends on how long a star lives
white dwarf
blue-white core of the star that is left behind and cooled, from a low-medium mass star
supernova
explosion of a high mass star
neutron stars
remains of high-mass stars
pulsars
spinning neutron stars
black hole
object with gravity so strong that nothing, not even light, can escape
binary stars
star systems that have two stars
eclipsing binary
a system where one star periodically blocks the light from another, dim star revolves around bright star
open clusters
cluster with loose, disorganized appearance, no more than a few thousand stars
globular clusters
large groupings of older stars, round, densely packed
spiral galaxies
galaxy that appears to have a bulge in the middle and arms that spiral outward
galaxy
huge group of single stars, star sytems, star clusters, dust, and gas bound together by gravity
elliptical galaxies
look like circles, old stars, contain billions of stars, little gas and dust between stars
irregular galaxies
irregular shapes, new stars, smaller than other galaxies
quasars
active young galaxies with giant black holes at their centers
scientific notation
way that scientist use to write really long numbers
big bang theory
theory that the universe formed in an instant, billions of years ago, in an enormous explosion
hubble's law
states that the farther away a galaxy is, the faster it is moving away from us
cosmic background radiation
leftover thermal energy from the big bang
solar nebula
large cloud of gas and dust such as the one that formed our solar system
planetesimals
small, asteroid-like, comet-like bodies
dark matter
matter that does not give off electromagnetic radiation
dark energy
mysterious new force that is causing the expansion of the universe to accelerate