53.____________________ the resistance of a gas to the flow of : 1777241
53.____________________ is the resistance of a gas to the flow of radiation.
54.The condition of ____________________ means that the force due to gravity pushing down on a layer is exactly equal to the pressure pushing outward on that layer.
55.Stars with masses greater than 1.1 solar masses use the ____________________ to convert hydrogen into helium and produce energy
56.Energy transport by ____________________ is important when photons cannot readily travel through a gas.
57.____________________ appear reddish in color due to the light emitted by the Balmer series of the hydrogen atom.
58.The pressure of an interstellar gas cloud depends on the cloud's ____________________ and ____________________.
59.A(n) ____________________ is a cool, dense cloud of dust and gas that is undergoing gravitational contraction.
60.A star on the ____________________ generates enough energy from nuclear fusion to halt gravitational collapse.
61.A(n) ____________________ is a subatomic particle produced in nuclear fusion that can travel through the sun and escape to space without interacting with any particles in the sun.
62.If energy is carried by the bulk motion of matter, that is called ____________________.