1. a) Assume we live in a Universe that is NOT expanding, but is static (staying
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Question
1. a) Assume we live in a Universe that is NOT expanding, but is static (staying the same size). Three galaxies (Galaxy Hubble, Galaxy Rubin, and Galaxy Einstein) are illustrated below. Galaxy Hubble and Galaxy Rubin are separated by 10 billion lightyears. Galaxy Einstein is located between Galaxy Hubble and Galaxy Rubin, at a distance of 4 billion lightyears from Galaxy Hubble. When the Universe was 2 billion years old, could Galaxy Hubble see Galaxy Einstein? Could Galaxy Rubin see Galaxy Einstein? Explain.
b) When the Universe was 9 billion years old, the supermassive black hole at the center of Galaxy Einstein began accreting gas and shining as a quasar. The quasar has continued shining to present day. At present day (when the age of the Universe is 14 billion years), does Galaxy Hubble see Galaxy Einstein? If so, does Galaxy Hubble see Galaxy Einstein as a galaxy with a quasar or a galaxy without a quasar? Does Galaxy Rubin see Galaxy Einstein? If so, does Galaxy Rubin see Galaxy Einstein as a galaxy with a quasar or a galaxy without a quasar?
Explanation / Answer
When the Universe was 2 billion years old, could Galaxy Hubble see Galaxy Einstein?
No, when Universe was 2 billion years old the Galaxy Einstein was young, in gaseous matter form, not so bright, so Galaxy Hubble could not have seen Galaxy Einstein
Could Galaxy Rubin see Galaxy Einstein? Explain.
Similar case like Galaxy Hubble unable to see dark gaseous Einstein. Galaxy Robin is far away from Einstein than Hubble, so it is difficult to see Galaxy Einstein by Galaxy Rubin.
a) When the Universe was 9 billion years old, the supermassive black hole at the centre of Galaxy Einstein began accreting gas and shining as a quasar. The quasar has continued shining to present day. At present day (when the age of the Universe is 14 billion years),
does Galaxy Hubble see Galaxy Einstein? If so, does Galaxy Hubble see Galaxy Einstein as a galaxy with a quasar or a galaxy without a quasar?
Yes, Galaxy Hubble see the Galaxy Einstein now. The Galaxy Hubble see Galaxy Einstein as galaxy with quasar because of its bright color.
Does Galaxy Rubin see Galaxy Einstein? If so, does Galaxy Rubin see Galaxy Einstein as a galaxy with a quasar or a galaxy without a quasar?
Yes, Galaxy Rubin see the Galaxy Einstein now, Galaxy Rubin see the Galaxy Einstein as a galaxy with a quasar.
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