Examlex
The Sun orbits the center of the galaxy about once every ____.
Q2: Supernovae are the main source of _
Q6: A medium-mass star evolves into a red
Q17: Many galaxies with erupting black holes are
Q28: Because of the period-luminosity relation for Cepheids
Q30: In the early universe, the electromagnetic and
Q33: Millisecond pulsars _.<br>A) are created in supernova
Q47: If luminosity depends on radius and temperature,
Q52: The laws of physics demand that a
Q63: Gravitational lensing is caused by _.<br>A) refraction
Q69: Outline the three steps to the solar