Why do astronomers speak in terms of redshifts rather than distances to faraway objects?
What will be an ideal response?
Distance is an uncertain quantity: do you mean current or distance when the light was emitted? Redshift is a measured quantity, whereas distance must be cycled through the Hubble Law with its inherent uncertainties.
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Which of the following does not provide evidence that Mars once had abundant liquid water on its surface?
A) the presence of features that look like dried up river beds B) the presence of what looks like sedimentary layers in some crater bottoms C) the presence of very old craters that appear to have been eroded by rain D) the presence of canali, discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell
What is the mass of a solid sphere that has a density 15.0 × 103 kg/m3 and a radius 10.0 cm?
A) 62.8 kg B) 4.56 kg C) 298 kg D) 3.58 × 106 kg E) 15.0 kg
It was the newly developed ________ theory which allowed Adams and Leverrier to predict the position of Neptune from the motions of Uranus
Fill in the blank(s) with correct word
The southern highlands of Mars date to which geological era?
A) Amazonian B) Hesperian C) Cenozoic D) Noachian