Best way to study mid terms is do assignments on mastering astronomy, and quiz your
self. on mastering astronomy theres a menu on side that says self study area, hundred of
question and little activities to do on your own to prepare for the best, to give you extra
boost closer to mid term, oct 18 and 21 were offering review sessions. note those days.
end of last class we were talking about how the sun powers it self
we went through whats called pro ton proton change nuclear reactions sun uses to convert
hydrogen and turn it into helium and inso doing it changes what kind of thing it to
another kind of thing, it changes matter or mass in to energy. sun takes matter and
converts it into energy, does it through wants called a fusion reaction.
-centre of sun is 15million degrees hot, had to be that hot so it can stick protons together,
hydrogen atoms, if you stick protons together what do they normal do. its to repel similar
electric chares repel. in order to get them to fuse, they have to move at incredible speeds,
so they can push through mutual repulsion. temperature is the description of how fast
particles are moving around in physics.
sun its core particles moving fast enough they can smash in to each other and stick.
approximately how hot is the sun all of the above, the temperature changes at different
points of the sun.
this is the temperature of the core 15000000
from the surface going into the core you pass through all these temperatures, sun has
many, many temperatures.
-The SOLAR THERMOSTAT stabilizes energy production in the core.
-sun is a giant ball of plasma own gravity wants to squish it and turn it into a black hole,
it hasn't happened. sun produces tremendous amount of heat, it produces outward
pressure that balances force of gravity. sun its a gas everything around it moving around
really quickly, sun can get hotter inside, or a little colder, depending on how stuff moves
around, for 5 billion years its managed to maintain its temperatures through what is called
the solar thermostat if a temperature gets to high air condition go in to low heater kick up.
-im showing you half of a diagram written in your textbook, you can work with solar
thermostat working with an increase or decrease in temperature, lets say for whatever
reason in the core of the sun the temperature starts to fall , the protons in the core of the
sun start to slow down, and they need to move quickly so they can stick to one another,
so they can fuse, if their is a cooling the rate of protons stick together slows down, the
more protons that encounter each others and don't stick is the less energy you get, the less
energy you get, the less outward pressure in the sun, the less outward pressure you have,
the more gravity starts to win, if gravity starts to win, it compresses the sun again,
compressing the sun drives proton closer and closer together, makes it more likely they
stick and it produces more energy and drives sun back to original configuration, with out
which life would be impossible in the universe. complicated sequence of steps core temperature stops protons slow down fusion rate drops energy production go down, the
pressure go down, and everything starts to collapse gravity starts to win, as gravity
collapse things, bring protons closer together energy generation rate go up and sun re
expands to original size, expan