What advantage do radio astronomers have over optical ones in mapping the entire Milky Way?
What will be an ideal response?
Dust clouds block our view of all but the nearest spiral arms, but 21-cm radio waves can map the hydrogen gas in spiral arms all around the galaxy.
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What do we mean by accretion in the context of planet formation?
A) the growth of planetesimals from smaller solid particles that collided and stuck together B) the formation of moons around planets C) the solidification of ices, rocks, and metal from the gas of the solar nebula D) the growth of the Sun as the density of gas increased in the center of the solar nebula
Which of the following is the best answer to the question, "Why does the Sun shine?"
A) As the Sun was forming, gravitational contraction increased the Sun's temperature until the core become hot enough for nuclear fusion, which ever since has generated the heat that makes the Sun shine. B) As the Sun was forming, nuclear fusion reactions in the shrinking clouds of gas slowly became stronger and stronger, until the Sun reached its current luminosity. C) The Sun initially began making energy through chemical reactions. These heated the interior enough to allow gravitational contraction and nuclear fusion to occur. D) The Sun initially began generating energy through nuclear fusion as it formed, but today it generates energy primarily through the sunspot cycle.
A rock is thrown upwards at an angle of 40° with respect to the horizontal. As the rock is rising in its trajectory, the horizontal component of its velocity
A) increases. B) decreases. C) remains the same. D) is zero. E) Cannot be determined without additional information.
Specific heat capacity of ice = 2,000 J/kg-°C latent heat of fusion of water = 334,000 J/kg specific heat capacity of water = 4,000 J/kg-°C As the ice is melting, the temperature of the ice-water mixture rises by __________
Fill in the blank(s) with correct word