nuclear fusion
process of combining small nuclei to form larger nuclei releasing large amounts of energy, source of the sun's energy
core
made up of ionized gas due to the extremely high temperature which causes nuclear fusion to occur
radiative zone
surrounds the core, energy radiates outward in the form of electromagnetic waves
convective zone
surrounds the radiative zone, energy moves outwards towards the surface as the gases rise and sink due to convection
sun's atmosphere
made up of the photosphere, chromosphere, and corona
photosphere
energy given off in this layer of the atmosphere is in the form of visible light
sunspots
cool areas on the sun within the photosphere that appear dark in color
chromosphere
thin layer of gases that glows with reddish light
corona
outermost layer of the sun's atmosphere, only visible during a solar eclipse
solar wind
electrically charged ions and electrons that flow outward from the corona to the rest of the solar system
prominence
great clouds of glowing gases that form huge arches that reach high above the sun's surface following curved magnetic field lines
solar flare
sudden outward eruption of electrically charged particles which can lead to the formation of coronal loops
coronal mass ejection
parts of the corona that are thrown off the sun
magnetosphere
space around Earth that contains a magnetic field
aurora
bands of light created in the sky from the interaction between solar wind and Earth's magnetosphere
star
ball of gases that give off tremendous amounts of electromagnetic energy
spectrum of light
display of colors and lines produced when the light from a star is passed through a spectrograph determining its composition and temperature
red star
coolest star
blue star
hottest star
apparent motion
motion of stars as it appears from Earth caused by the movement of Earth
Doppler effect
apparent shift in the wavelength of light emitted by a light source moving toward or away from an observer
blue shift
light waves from a star appear to have shorter wavelengths as the star moves toward Earth
red shift
light waves from a star appear to have longer wavelengths as the star moves away from Earth
light-year
distance that light travels in one year, 9.46 trillion km
parallax
the apparent shift in a star's position when viewed from different locations
apparent magnitude
the brightness of a star as it appears to us on Earth
absolute magnitude
the true brightness of a star or how bright the star would appear if all the stars were at a standard, uniform distance from Earth
luminosity
total amount of energy a star gives off each second
Hertzsprung-Russell diagram
plots the surface temperatures of stars against their luminosity
main sequence
a band containing most stars that extends from cool, dim, red stars at the lower right to hot, bright, blue stars at the upper left on the HR diagram
nebula
a cloud of gas and dust from which a star is formed
law of universal gravitation
all objects in the universe attract each other with a force that increases as the mass of any object increases or as the distance between the objects decreases
protostar
the shrinking, spinning region begins to flatten into a disk that has a central concentration of matter
main sequence stage
the second and longest stage in the life of a star where hydrogen fuses into helium
giant
large, red star that forms as the star's shell of gases grows cooler and expands
white dwarf
gravity causes the remaining matter in the star to collapse inward forming a hot, extremely dense core
supernova
the star becomes so dense that the outler layers rebound and explode outward releasingenergy and stellar material into space
neutron star
formed after a supernova in large mass stars where the core contracts into a very small, dense ball of neutrons that emits pulses of radio waves
pulsar
a beam of radio waves emitted by a neutron star
black hole
a star continues to contract in its final stages due to its large mass crushing its core, gravity is so great that even light cannot escape
convection
The movement of matter due to differences in density that are caused by differences in temperature
radiation
the movement of energy in the form of electromagnetic waves through space, how energy travels from the sun to Earth
conduction
the movement of energy through a medium