Astronomy Practice Exam

What is referred to as the surface of the sun?

1. Chromosphere

2. Photosphere

3. Corona

4. Geosynchronous Orbit

The correct answer is: Photosphere

The photosphere is indeed referred to as the surface of the sun. It is the layer from which sunlight is emitted and is the visible surface that we see when we look at the sun. The photosphere has a temperature of about 5,500 degrees Celsius (around 5,800 Kelvin) and consists of gas, primarily hydrogen and helium, with a relatively low density compared to the inner layers of the sun. It appears grainy when viewed through a telescope due to the presence of convection cells known as granules, which are caused by the rising and sinking of hot plasma. While the chromosphere and corona are important layers of the sun, they are located above the photosphere. The chromosphere lies above the photosphere and is often observed during solar eclipses as a reddish glow, while the corona is the sun's outer atmosphere, extending far into space and visible as a halo during total solar eclipses. Geosynchronous orbit does not relate to the sun but rather describes a specific orbit of satellites around Earth.