Sun

Question 1

sun size

Answer 1

1 AU, angular size 0.5 degrees

Question 2

sun radius, mass, density, temperature

Answer 2

700,000 km radius (110 earths), 300,000x earths mass (1000 jupiters), avg. denisty = 1.4, 55000 C (determined by light spectrum).

Question 3

sun rotation

Answer 3

differential; 25 days at equator, 35 at poles.

Question 4

sun energy

Answer 4

as it travels towards surface, it is continuously absorbed and reemitted at decreasing temperatures.

Question 5

sun structure under surface

Answer 5

core, radiation zone, convection zone

Question 6

radiation zone

Answer 6

300,000 km wide, not so ionized, transparent to radiation, temperature decreases.

Question 7

convection zone

Answer 7

200,000 km wide, not so ionized, photons absorbed and energy moves very slow.

Question 8

sun structure on surface (what we see)

Answer 8

photosphere; transparent, visible edge, 500km height, 0.2 density, 6000 K.

Question 9

sun structure above surface

Answer 9

chromosphere, transition zone, corona

Question 10

chromosphere

Answer 10

2000 km, dimmer, cooler-reddish

Question 11

transition zone

Answer 11

8500 km, temperature increases.

Question 12

corona

Answer 12

thin, hot, transparent, highly ionized, emission spectrum and x-rays, temperature above 10^6 K.

Question 13

solar wind

Answer 13

particles at 500km/second out to more than 50 AU, 10^6 tons/second.

Question 14

solar weather

Answer 14

coronal activity, mass ejections, potentially dangerous for power and communications especially near solar maximum activity years.

Question 15

sun elements

Answer 15

91% hydrogen, 9% helium, some carbon, nitrogen, oxygen, etc. partially ionized.

Question 16

what is energy production in suns core

Answer 16

hydrogen undergoes nuclear fusion into helium

4H -> 1He + energy

Question 17

requirements for energy production in sun

Answer 17

high temp. (15 million K) and high pressur (200 billion atm) to overcome repulsion between protons (H nuclei).

Question 18

activity caused by suns magnetism

Answer 18

sunspots: dark spots (10k to 100k km, last for days)

prominences: looks like fire going up (100k km high, last for hours-weeks)

flares: looks like fire curving like an ocean wave (lasts minutes to hours).

Question 19

why does suns magnetism cause flares, spots, etc.

Answer 19

its differential rotation causes magnetic field lines to become intertwined after several rotations, creating regions of intense magnetic fields and thus, spots, flares, etc.

Question 20

solar cycle

Answer 20

annual change in number of sunspots and flares, approx. 11 years