The Sun (Earth, Moon and Sun) Flashcards
(31 cards)
What is it from Earth to the sun?
150 million km or 1 Astronomical unit.
What is the diameter of the Sun?
1.4 million km just over 100x diameter of the Earth.
What gases make up the sun and how much?
Hydrogen (75%)
Helium (25%)
Why is the sun so important?
Provides all the heat, light and energy requirements for life on Earth.
What is the visible surface of the sun called?
The photosphere
What is the temperature of the visible surface of the sun?
The photosphere’s temp is 5800K
What the the relatively thin ‘sphere of colour’ above the photosphere?
The chromosphere
What is the extensive outline which is the glowing region of ionised gas making up the Sun’s atmosphere?
The corona
What is the thickness of the chromosphere?
2000km
Why is the chromosphere not normally visible?
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.
What is the temperature of the corona?
2 million K which is hot enough to emit X-rays.
What is nuclear fusion?
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.
What is the temperature of the sun’s core?
15 million K
How many tonnes of of matter is lost each second by the sun?
4 million tonnes.
What is the total mass of the sun in tonnes?
2.0 x 10(to the power of)27
What are sunspots?
Cooler areas of the photosphere that correspond to strong localised magnetic fields.
How big are sunspots?
About the size of the earth.
What is an umbra?
A central darker region, about 2000K cooler than the photosphere
What is a penumbra?
A lighter (i.e. Less dark than umbra) surrounding area, with a temperature about 200K cooler than the photosphere.
How does the sun rotate?
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.
How long is the solar cycle?
The regular pattern of 11 years for sunspots. During which number of sunspots increases to a maximum before falling again.
What is a Butterfly diagram?
The chart which shows the general pattern of the positions of sunspots.
What is the Maunder Minimum?
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.
How can you find the rotation period of the sun?
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.
