Kepler originally proposed that the planets were spaced apart by ____.

Kepler originally proposed that the planets were spaced apart by ____.
 
  a. five spheres
 b. five regular solids
  c. six tetrahedrons
 d. five epicycles
 e. six regular solids

Question 2

Most of the energy emitted by a pulsar _____.
 
  a. is carried away as a pulsar wind' of high-speed atomic particles
 b. produces strong gravitational waves that radiate for several light years
 c. ionizes the supernova remnant around the pulsar
 d. is in the form of neutrinos
 e. is carried away by the high-energy beam emerging from the poles of the pulsar

Question 3

Kepler's first law of planetary motion defied what long-held belief with ancient astronomers?
 
  a. a heliocentric Universe
 b. a geocentric Universe
 c. uniform circular motion
  d. parallax of newborn stars
  e. perfection of the heavens

Question 4

The highest luminosity burst of radiation observed from a pulsar is the result of _____.
 
  a. the pulsation of a neutron star's surface
 b. a hot spot that rotates around the equator of a pulsar
 c. a spinning beam of radiation emerging from the pulsar's poles
 d. the rotation of an accretion disk transferring matter to the pulsar's surface
  e. the revolution of a binary companion that eclipses the pulsar, then reveals it