MCQ Detailed View

The Sun, being the central star of our solar system, consists of multiple layers, each with unique properties. The visible surface of the Sun, the part we see from Earth with the naked eye, is called the photosphere. The term "photosphere" comes from the Greek words "photo" meaning light and "sphere" meaning ball or layer, which together mean "the sphere of light." This is the layer that emits the sunlight that reaches our planet.

The photosphere is not a solid surface but a layer of hot, glowing gases, mainly hydrogen and helium. It has an average temperature of about 5,500°C (9,932°F). The light from this region takes around 8 minutes and 20 seconds to reach Earth. The photosphere is where sunspots are observed, appearing as darker areas caused by strong magnetic fields and relatively cooler temperatures.

Above the photosphere is the chromosphere, a thin layer that appears reddish during solar eclipses due to hydrogen gas emission. Beyond that lies the corona, the Sun's outer atmosphere, which extends millions of kilometers into space and can be seen during a total solar eclipse.

Other terms like thermosphere and leutosphere do not refer to any actual solar layers. The thermosphere is a layer of Earth's atmosphere, while "leutosphere" is not a recognized scientific term in astronomy.

The photosphere is essential for understanding solar phenomena such as solar flares, sunspots, and solar radiation, which directly affect space weather and Earth's climate. Studying this layer allows scientists to learn more about the Sun's magnetic field and its influence on the solar system.

The correct answer is Option D: Photosphere, as it is the official name of the Sun’s visible surface from which sunlight and most solar radiation are emitted.