Astro 1 Exam 3 | Q&A Latest 2024/2025 | 100% PASS

Astro 1 Exam 3 | Q&A Latest 2024/2025 | 100% PASS what is the sun comprised of? - Answer -73% hydrogen 25% helium why is the sun stable? - Answer -outward force of gas pressure; inward force of gravity Where does the gas pressure in the sun come from? - Answer -nuclear fusion reactions in the core at temperatures of 15 million degrees What is the diameter of the sun compared to earth? mass? luminosity (compared to 100W lightbulbs? - Answer -diameter-109x; mass- 333,000; luminosity- 4 x 10^24 What percent of mass in the solar system comes from the sun? - Answer -99.9% how long has the sun been shining? how much longer will it shine? - Answer -4.5 billion years; 5.5 billion years what are sunspots? - Answer -slightly cooler regions on the sun's surface what causes sunspots? how long are their cycles? - Answer -magnetic activity preventing hot material from rising to that region. they have 11 year cycles what comprises helium-4? What does it release? What is it called? - Answer -4 protons combine to make helium-4 (2 protons, 2 neutrons); produces gamma rays; it is called the proton-proton chainWhat is the first step in Nuclear fusion? - Answer -two protons stick together and one changes into a neutron to produce deuterium (1 proton and 1 neutron) What is the second step in Nuclear fusion? - Answer -deuterium plus proton makes helium-3 (2 protons and 1 neutron bound together) What is the third step in nuclear fusion? - Answer -two helium-3 molecules combine to make helium-4 and 2 protons When is energy created in