1.3 The Sun Flashcards
What is the diameter of the sun?
1.4 million km (about 100 times the diameter of the Earth).
What are the two main gases that the sun is made of and their percentages?
Hydrogen (75%) and helium (25%).
What is the temperature of the suns photosphere?
5800 K.
How thick is the suns chromosphere?
2000 km.
What reaction happens in the core of the sun to make the suns energy?
Nuclear fusion reactions where hydrogen nuclei (protons) are able to fuse together to make helium nuclei in a series of reactions called the proton-proton chain. A burst of energy is released when they fuse.
What are sunspots?
They are cooler areas of the photosphere. They appear as small dark patches on the photosphere but they are actually about the same size as Earth!
What’s an umbra?
A central darker region, about 2000 K cooler than the photosphere.
What’s a penumbra?
A lighter surrounding area with a temperature about 200 K cooler than the photosphere.
What is the suns rotational period?
It varies from 25 days at its equator to 36 days at its poles
What is the temperature of the corona?
2,000,000 K.
What is the photosphere?
The suns visible surface.
What is the chromosphere?
A sphere of colour above the photosphere.
What is the corona?
It’s the ‘crown’ which makes up the suns atmosphere.
Describe two methods we can use to observe the sun?
- Project an image of the sun on paper.
2. Use a H-alpha or Mylar filter on a telescope.
What is the solar cycle?
The relative number of sunspots follows a regular 11 year pattern called the Solar Cycle.
