6. Betelgeuse: The star Betelgeuse in the constellation Orion might go supernova any day now.
\ldots or perhaps it already has! Since it is 600 lightyears away, the light from the explosion
would not be expected to reach us until 600 years after the explosion happened. In
astrophysics, we will learn to say that we are currently \textquotedbl{}outside the lightcone of the
explosion\textquotedbl{}.
a) If Betelgeuse went supernova 599 years ago, releasing energy $E_{\text{Betelgeuse supernova}}$ Joules of
energy, what maximum energy should we expect to hit a square meter of Earth next year,
when the shockwave reaches us? Express your answer in terms of the distance to Betelgeuse,
$r_{\text{Betelgeuse}}$
b) Your expression in Part A gives the maximum energy per square meter. Why might some
parts of the planet receive more or less energy than others when the shockwave reaches us?
c) Now, plug in the numbers with their units. The distance to Betelgeuse is about 600 lightyears.
Each lightyear is $9.46 \times 10^{15}$m. The energy that might be released by the supernova is $10^{44}$
Joules.
