How can the Sun be observed safely?
Through a pinhole camera or a special solar filter.
The Sun's diameter and its distance from Earth
The Sun's diameter is 1.4million km and it is 150million km from Earth.
The temperature of the Sun
At the photosphere the temperature is 5800K, but the Sun is a lot hotter at the corona, with a temperature of 2million K.
Sunspots can be seen as dark spots on the Sun through a telescope. This is because they are cooler than the rest of the Sun. Sunspots can be used to observe the Sun's rotational period, as they appear to move.
The Sun's rotational period
At the equator of the Sun, the rotational period is 25 days, but at the poles the rotational period is 36 days.
How the Sun's energy is generated
The Sun's energy is generated by nuclear fusion reactions at its core, converting hydrogen into helium.
How the aurorae/Northern lights are formed
Sometimes the Sun blows out some charged particles into the Solar System. This is the solar wind. This solar wind once reached the Earth and the charged particles were let off into the Earth's atmosphere, exciting the air particles and creating light. This light can be seen at the North Pole and is therefore known as the Northern lights. The scientific name for the Northern lights is 'aurorae'.