Edexcel GCSE Astronomy Topic 10 Solar astronomy: a complete overview of the Sun's structure, fusion, sunspots and the solar wind

What Topic 10 actually demands

Solar astronomy is a structure-and-process topic: how the Sun is built, how it makes energy, and how its activity reaches the Earth. It rewards ordered description (the internal regions) and clear explanation (fusion, sunspots, the solar wind).

This guide walks through the dot points of the topic, then sets out the exam patterns Pearson repeats. Each dot point has a matching page with practice questions; this overview ties them together.

Structure and energy production

Observe the Sun safely by telescopic projection or an H-alpha filter. From the centre out: the core (fusion), radiative zone (radiation), convective zone (convection) and photosphere (the visible surface, about 5800 K). Energy comes from the proton-proton chain (hydrogen to helium, with the mass lost converted into energy). The atmosphere above is the chromosphere and the very hot, tenuous corona.

Sunspots, the solar wind and the magnetosphere

Sunspots are cooler, darker magnetic regions; tracking them gives the solar rotation period (about 25 to 27 days), and their number follows an 11 year cycle. The solar wind (charged particles from the corona) causes aurorae, geomagnetic storms and shapes comet tails. The Earth's magnetosphere deflects most of it, trapping particles in the Van Allen Belts.

How Topic 10 is examined

A typical Edexcel profile for solar astronomy:

• Description. The internal regions and their energy transfer, and the proton-proton chain.
• Explanation. Sunspots as cooler magnetic regions, and the solar wind's effects.
• Calculation and graphs. The solar rotation period and the 11 year cycle from sunspot data.
• Recall. Safe observation, the corona, and the magnetosphere.

Check your knowledge

A mix of description and explanation questions covering Topic 10. Attempt them under timed conditions, then check against the solutions.

1. State the Sun's internal regions in order from the centre. (1 mark)
2. State what is fused into what in the proton-proton chain, and where the energy comes from. (2 marks)
3. State a safe method of observing the Sun with a telescope. (1 mark)
4. Explain why sunspots appear darker than the surrounding surface. (2 marks)
5. State the approximate length of the solar cycle. (1 mark)
6. State what the solar wind is and one effect it has at the Earth. (2 marks)
7. State the role of the Earth's magnetosphere. (1 mark)