Unit 1 Sun

Question 1

Sun’s diameter

Answer 1

1,400,000km

Question 2

Corona

Answer 2

Top of the solar atmosphere. 2 million degrees K. Ionised gas that is hot enough to emit X-rays.

Question 3

Chromosphere

Answer 3

Lower part of the Sun’s atmosphere. Temperature ranges between 6000 degrees K to 2 million degrees K.

Question 4

Solar wind

Answer 4

Flow of charged particles from the Sun.

Question 5

Photosphere

Answer 5

Surface of the Sun. 5800 degrees K.

Question 6

Rotational period at equator

Answer 6

25 days

Question 7

Rotational period at poles

Answer 7

36 days

Question 8

Thermonuclear fusion

Answer 8

Binding of atomic nuclei to form new elements. In the Sun it is generally hydrogen colliding with hydrogen to make helium.

Question 9

Partial eclipse

Answer 9

Part of the Sun is blocked out due to the Moon.

Question 10

Full eclipse

Answer 10

The whole sun is blocked by the Moon giving complete darkness.

Question 11

Lunar eclipse

Answer 11

The Earth is between the Sun and the Moon making it red.

Question 12

Solar

Answer 12

The Moon gets in the way of the Sun and blocks the view of the Sun from the Earth.

Question 13

Distance to Sun: 1AU

Answer 13

150,000,000km

Question 14

What is the Sun made of?

Answer 14

75% hydrogen, 25% helium and small amounts of other elements.

Question 15

Sunspots

Answer 15

Sunspots are cooler areas of the photosphere that correspond to strong localised magnetic fields.

Question 16

Umbra (sunspot)

Answer 16

Central, darker, cooler region. About 2000 degrees K cooler than the photosphere.

Question 17

Penumbra (sunspot)

Answer 17

Lighter surrounding area with a temperature about 200 degrees K cooler than the photosphere.

Question 18

Solar cycle

Answer 18

The 11 year pattern which the total number of sunspots reaches it’s maximum before falling again.

Question 19

The Butterfly Diagram

Answer 19

The traditional way to plot sunspots with time(Y) on the x-axis and latitude(^o) on the y-axis.

Question 20

Solar Wind

Answer 20

Solar wind is a steady stream of particles (mainly protons and electrons) flowing outwards in all directions from the Sun’s corona at speeds of typically 400 km/s.

Question 21

Fast Solar Wind

Answer 21

This is thought to be from coronal holes (cooler areas of the corona nearer the Sun’s magnetic poles) where open magnetic field lines (as opposed to closed “loops”) permit charged particles from the photosphere to escape at speeds as fast a 850 km/s.

Question 22

Solar Eclipse

Answer 22

Moon between the Earth and Sun.

Question 23

Umbra (eclipse)

Answer 23

Area that experiences full solar eclipse during a solar eclipse. Appears as a darker shadow on the Earth from space.

Question 24

Penumbra (eclipse)

Answer 24

Area that experiences partial solar eclipse during a solar eclipse. Appears as a lighter shadow on the Earth from space.

Question 25

Diamond ring (eclipse)

Answer 25

At the beginning and end of totality in a solar eclipse when one bead of sunlight shines through a valley on the moon.

Question 26

Lunar eclipse

Answer 26

When the Moon is in full moon it is possible to have a lunar eclipse. This is when the Moon is behind the Earth and refraction of the Sun’s light makes the Moon appear an orange/red colour.

Question 27

Equation of Time

Answer 27

Eot= Apparent Solar Time - Mean Solar Time

Question 28

How many days of the year is the EoT 0?

Answer 28

4 days.

Question 29

What are the names of the two aurorae?

Answer 29

Aurorae Borealis and Aurorae Australis.

Question 30

What causes aurorae?

Answer 30

Electrons from the solar wind accelerate at high speeds into the atmosphere directed by the Earth’s magnetic field. As the atoms that the electrons have excited de-excite they emit certain colours of light.