Problem 1: In
a system. The volume outside the boundary is called the surroundings of the system. The sum of
the system and its surroundings is called the universe, which is an isolated system.
In astrophysics, on the other hand, universe is all of space and time (space-time) and its contents
including planets, moons, minor planets, stars, galaxies, and all known and unknown matters and
energy. Today, we know that the universe is expanding at an increasing rate, which is one of the
most fascinating scientific discoveries. With today’s advanced technology, such as Hubble Space
Telescope, we can measure this expansion rate very accurately.
Now, assume that our universe is an isolated, single-phase system:
A) How do you explain this expansion by the 2nd Law of Thermodynamics? What is the entropy
balance of our universe?
B) When do you think this phenomenon will stop? And what will be the entropy balance then?
C) What will be the temperature and pressure profiles across the universe when the expansion
stops?
D) Once the expansion stops, would you able to generate electric energy from the sun using a
solar system? Explain why.
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