Space and time are interconnected according to special relativity. Because of that, coordinates
have four components (three position coordinates x, y, z, one time coordinate t ) and can be ex-
pressed as a vector with four rows as such:
ct
x
y
z
The spaceship from problem A.4 (Special Relativity - Part I) travels away from the Earth into the
deep space outside of our Milky Way. The Milky Way has a very circular shape and can be ex-
pressed as all vectors of the following form (for all 0 ≤ ϕ < 2π):
ct
sin ϕ
cos ϕ
(a) How does the shape of the Milky Way look like for the astronauts in the fast-moving space-
ship? To answer this question, apply the Lorentz transformation matrix (see A.4) on the circular
shape to get the vectors (ct0
, x0
, y0
, z0
) of the shape from the perspective of the moving spaceship.
(b) Draw the shape of the Milky Way for a spaceship with a velocity of 20%, 50%, and 90% of the
speed of light in the figure below (Note: The ring shape for a resting spaceship is already drawn.):
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