Question 01/04
ISOTROPIC UNIVERSE
Observer O is located in an infinite space and is bombarded
by particles (shown in blue) coming from infinity and moving
along straight lines in
random directions. This "rain" of particles is isotropic in its directions.
At large distance from the observer there is a region of scatterers S
shown in red. The region contains many scatterers of the
blue particles. The scatterers are not isotropic.
However, their orientation is random. Can the observer O detect
the presence of the region S in the space by simply observing
the distribution of particles arriving at O from different directions?
Note: You may assume that the scatterers are "dilute", i.e. a
particle is not scattered more than once.
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