What Is The Sun Doing?

Front 1

Naive expectations of the sun are:

Back 1

1. If it has no source of internal energy generation, it will loose heat
2.if has internal engine supplying fresh energy, able to maintain itself, eventually run out of fuel

Front 2

Why are the naive expectations wrong?

Back 2

GRAVITY CHANGES EVERYTHING, the sun cannot cool down

Front 3

What happens when the sun losses radiant energy (heat or light)?

Back 3

SUN GETS EVEN HOTTER AS IT'S FUEL SUPLY DIMINISHES (inner parts)

Front 4

How does the sun get even hotter then the fuel supply diminishes?

Back 4

shrinking a little, converting gravitational potential energy to heart

Front 5

What is the internal engine for the sun and other planets?

Back 5

NUCLEAR REACTIONS

Front 6

Why can't the sun cool down?

Back 6

1.if too lose internal heat energy, particles rushing less rapidly and provide less sustaining pressure to support weight
2. the act of contraction of the sun would lead to conversion of gravitational potential energy into heat
3.some converted energy gets radiated away, the rest stays in sun and raises temperature

Front 7

How is the outward-flowing energy constantly replenished?

Back 7

INTERNAL SOURCE, permits the sun to maintain equilibrium

Front 8

Kelvin contraction

Back 8

source of outflowing energy while the sun was actually forming

Front 9

How did the sun start?

Back 9

low-density cloud of gas widely distributed in space

Front 10

What happened to low-density cloud of gas?

Back 10

condensed, under effects of gravity, to form denser lump, got hotter by releasing gravitational potential energy

Front 11

Why didn't the sun not collapse down to a very dense, much smaller body?

Back 11

LUMP eventually got so dense that it become opaque: the heat energy within it could not easily be radiated away to empty space since each emitted photon had a good chance of running into another atom

Front 12

What brought the lump to a haut?

Back 12

PRESSURE from random rapid motions of atoms whizzing around

Front 13

What was an argument against Kelvin contractions?

Back 13

Theory of natural selection proposed by Charles Darwin

Front 14

What did theory natural selection suggest about the age of the earth?

Back 14

the earth has to be much older than ten million years, observed diversity of species

Front 15

How else can we prove that there are hardly any changes in the size of the sun?

Back 15

elipses, since in the past they did not see total eclipses, then sun has not shrunk very significantly in size over the last few thousand years at least

Front 16

How was the sun made hot? (important)

Back 16

the sun's contractions under self-gravity and the consequent release of gravitational potential energy, THIS WOULD HAVE BEEN THE CASE IF THERE WERE NO NUCLEAR REACTIONS AT ALL

Front 17

What allowed the nuclear reactions to occur within the sun?

Back 17

extreme heat

Front 18

What maintains the sun's heat?

Back 18

NUCLEAR REACTIONS, but didn't originally produce it

Front 19

What would happen if there was no nuclear reactions within the planets?

Back 19

the universe will still be full of hot star-sized lumps with contractions just as Kelvin hypothesized BUT WILL NOT BE VERY LONG-LIVED

Front 20

What are the factors that do not explain sun's longevity?

Back 20

1. gravitational contractions
2. chemical reactions