Astronomy

Choose the Correct Answer

Correct Answer : Option a

Explanation
Statement 1 is correct: The Chromosphere is the second layer of the Sun’s atmosphere, located above the Photosphere and below the Corona.

Statement 2 is not correct: The Photosphere is denser than the Chromosphere and as we move outward from the Sun’s core, density decreases. The Chromosphere is a thin layer with lower density compared to the Photosphere.
Structure of the Sun

The solar interior, from the inside out, is made up of the core, radiative zone and convective zone. The solar atmosphere above consists of the photosphere, chromosphere, and the corona (solar wind is an outflow of gas from the corona).
Core: The Sun’s energy source, where nuclear fusion occurs. It is extremely hot (~15 million°C) and dense due to high pressure. It converts hydrogen into helium, releasing vast amounts of energy.

Radiative Zone: It Surrounds the core and extends about 70% of the way to the surface. Energy is transferred outward by radiation, taking thousands of years to escape. It is slightly cooler than the core, allowing some atoms to absorb and re-emit energy.
Convective Zone: The outermost layer of the Sun’s interior. The energy moves through convection, where hot gases rise and cooler gases sink. This motion creates the granulated appearance of the Sun’s surface.

Photosphere: The photosphere is also named the apparent surface of the Sun. Since the Sun is wholly made of gas, there is no solid surface (like there is on Earth). However, when we observe the Sun, there is a depth past which the density of the gas becomes so high that we cannot see through it. This region is called the photosphere, or as mentioned the apparent surface. This is the disk that one sees in the sky when one looks at the Sun through a telescope that has a filter, or as a projection on, for example, a sheet of paper.

Chromosphere: The chromosphere is the layer above the photosphere and is thicker than it. With a very low density, it's impossible to observe it without narrowband filters or during a total solar eclipse due to the brightness of the photosphere behind it. Furthermore it’s less dense than the photosphere.

Corona: The Sun's corona is its outermost layer, made of extremely hot plasma. It extends millions of kilometers into space and is much hotter than the Sun’s surface. The corona is usually hidden by the Sun’s brightness but becomes visible during a total solar eclipse as a glowing halo around the Sun. It plays a crucial role in solar wind and space weather.