The Sun (Earth, Moon and Sun)

Question 1

What is it from Earth to the sun?

Answer 1

150 million km or 1 Astronomical unit.

Question 2

What is the diameter of the Sun?

Answer 2

1.4 million km just over 100x diameter of the Earth.

Question 3

What gases make up the sun and how much?

Answer 3

Hydrogen (75%)

Helium (25%)

Question 4

Why is the sun so important?

Answer 4

Provides all the heat, light and energy requirements for life on Earth.

Question 5

What is the visible surface of the sun called?

Answer 5

The photosphere

Question 6

What is the temperature of the visible surface of the sun?

Answer 6

The photosphere’s temp is 5800K

Question 7

What the the relatively thin ‘sphere of colour’ above the photosphere?

Answer 7

The chromosphere

Question 8

What is the extensive outline which is the glowing region of ionised gas making up the Sun’s atmosphere?

Answer 8

The corona

Question 9

What is the thickness of the chromosphere?

Answer 9

2000km

Question 10

Why is the chromosphere not normally visible?

Answer 10

The light from the photosphere is too dominant. However it can be seen as a slender pink ring just before totality is reached during a solar eclipse.

Question 11

What is the temperature of the corona?

Answer 11

2 million K which is hot enough to emit X-rays.

Question 12

What is nuclear fusion?

Answer 12

The reactions that happen in the central core of the sun and is the sun’s source of energy. The heat of the core allows hydrogen nuclei (protons) to fuse to make helium nuclei in a series of reactions called the proton-proton chain.

Question 13

What is the temperature of the sun’s core?

Answer 13

15 million K

Question 14

How many tonnes of of matter is lost each second by the sun?

Answer 14

4 million tonnes.

Question 15

What is the total mass of the sun in tonnes?

Answer 15

2.0 x 10(to the power of)27

Question 16

What are sunspots?

Answer 16

Cooler areas of the photosphere that correspond to strong localised magnetic fields.

Question 17

How big are sunspots?

Answer 17

About the size of the earth.

Question 18

What is an umbra?

Answer 18

A central darker region, about 2000K cooler than the photosphere

Question 19

What is a penumbra?

Answer 19

A lighter (i.e. Less dark than umbra) surrounding area, with a temperature about 200K cooler than the photosphere.

Question 20

How does the sun rotate?

Answer 20

The sun does not rotate as a solid body. It’s rotation periods varies from 25 days at its equator to 36 days at its poles.

Question 21

How long is the solar cycle?

Answer 21

The regular pattern of 11 years for sunspots. During which number of sunspots increases to a maximum before falling again.

Question 22

What is a Butterfly diagram?

Answer 22

The chart which shows the general pattern of the positions of sunspots.

Question 23

What is the Maunder Minimum?

Answer 23

The period between the years of 1645 and 1715 when the sun was relatively inactive and very few sunspots were observed. This corresponds with a period of extremely cold winters in Europe.

Question 24

How can you find the rotation period of the sun?

Answer 24

You observe a group of sunspots, recording their position and timing how many days later the spots return to the same position. This would be the time of one rotation.

Question 25

What is the solar wind?

Answer 25

This is a steady stream of charged particles (mainly protons and electrons, but with trace of ions of helium and other elements) flowing outwards in all directions from the sun’s corona at speeds of typically 400km/s.

Question 26

What are coronal holes?

Answer 26

Cooler regions of the corona close to the sun’s magnetic poles where open magnetic field lines escape more easily at speeds as fast as 850 km/s. This is where fast solar wind is thought to have originated from.

Question 27

What are prominences?

Answer 27

Huge clouds of cooler gas in the Sun’s atmosphere.

Question 28

What are filaments?

Answer 28

Huge clouds of cooler gas in the Sun’s atmosphere that appear as dark silhouettes against the brighter photosphere.

Question 29

What are solar flares?

Answer 29

Sudden releases of energy

Question 30

What is a transit?

Answer 30

When a planet travels in front of the sun and it looked like a dark shadow.

Question 31

What type of radiation is emitted from exceptionally hot regions of the sun?

Answer 31

X-rays.