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30 Cards in this Set

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Galileos telescopic discoveries of mountains on the moon and spots on the sun were contraversial because the sugested that the sun and moon
were not perfect spheres
the force due to gravity depends on
the mass of each object and the distance betweeen the 2 objects
hallys comethas an orbital period of 76 yrs what is the average distance of 65 AU what is the approximate orbital period of this object
524 yrs
ultravoilet radiation from a star
will not penetrate earths atmosphere and reach the ground
long wavelentgh visible light
will appear red in color to the average to the average human eye
which electromagnetic radiation has smallest frequency
radio
which electromagnetic radiation has lowest energy
infrared radiation
increasing the diameter of a telescope
increases its light gathering power and resolving power
what is the magnification of a telescope and eyepeice has a focal length of 2.0cm
100 times
an atom can be excited
if it collides with another atom or electron and if it absorbs a photon
why dont we see hydrogen balmer lines in the spectra of stars with temperatures of 3200k
these stars are so cool that nearly all of the hydrogen atoms are in the ground state.
the radiation emitted from a star has a maximim intensity at a wavelength of 300nm. what is the temp of this star?
10000k
most of the light we see coming from the sun originates in the
photosphere
sunspots are known to be magnetic phenomena because
the Zeeman effect is observed in sunspots
which is evidence that convection occurs in the layers just below the sun's photosphere
the centers of granules are hot and moving away from the center of the sun
A_____ is belived to occur when energy, stored in a twist in the solar magnetic field above a sunspot, is suddenly released
solar flare
absolute visual magnitude is
the apparent magnitude of a star observed from a distance of 10 pc
in the H-R diagram 90 percent of all stars are
on the main sequence
the _____ of a star is a measure of hte total energy radiated by the star in one second
luminosity
an elcipsing binary will
always be a spectroscopic binary
which of the following must obey the mass-luminosity relation
the main sequence stars
protostars are difficult to observe because
short,cocoons of stars and gas, radiate infrared
nuclear reactions in a stars core remain under control so long as
pressure depends on temp
interstellar gas clouds may collapse to form stars if they
encounter a shock wave
the main sequence has a limit ar the lower end because
there is a minimum temp for hydrogen fusion
there is a mass-luminosity realtion because
stars support their weight by making energy
the lowest mass object that can initiate thermonuclear fusion of hydrogen has a mass of about
0.08M
absorbtion lines due to the interstellar medium indicate that some components of the interstellar medium are cold and of very low density because
the lines are extremly narrow
in ad 1054 chinese atronomers observed the appearence of a new star whose location is now occupied by
a pulsar, a neutron star, supernova remnant
an isolated black hole in space would be difficult to detect because
very little matter would be falling into it