What do we mean by length contraction in relativity?
A) It is the idea that if you measure the size of an object moving relative to you, you will find that it is shorter in every direction than it would be at rest. That is, length, width, and height are all shorter for an object when it is moving by you.
B) It is the idea that moving objects look smaller than nonmoving objects, but their sizes have not really changed.
C) It is the idea that if you measure the size of an object moving relative to you, you will find that in the direction of motion it is shorter than it would be at rest, while its size in other directions is unchanged.
D) It is the idea that if you travel very fast, you'll notice yourself getting shorter.
Question 2
According to observations, what type of galaxy was much more common when the universe was 2 billion years old?
A) elliptical galaxies
B) spiral galaxies
C) irregular galaxies
D) We can't say, because we are living at a time when the universe is 14 billion years old, not 2 billion years.
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