The Temperature Conundrum of the Sun Solved

In News

Researchers along with an Indian scientist from the Indian Institute of Astrophysics have solved the sun conundrum that has puzzled solar physicists for a long time.

In-Detail

• The temperature of the sun at its core is 15 million degrees Celsius.
• At the surface layer called the photosphere, it is merely 5,700 degrees C.
• While it is natural to expect from any heating body without an external source to heat it, the temperature tends to decrease as it goes outside.
• But, the sun’s atmosphere, known as the Corona has a higher temperature than the photosphere.
• From outward of photosphere temperature increases to one million degrees C or more in the Corona. This stretches to over a million kilometres.
• This conundrum has puzzled solar physicists.

Spicules

• The Sun has many geyser-like jets known as Spicules.
• These appear as hairs in a photograph, but these are 200-400 km wide and rise to a height of about 5000km above the solar surface.
• These spicules are key to answering the puzzle.
• Researchers have suspected that these spicules act as conduits for heat and energy to get transferred from the lower atmosphere, bypassing the photosphere and reaching the upper atmosphere.
• The current research shows how these Spicules are formed and act as conduits through which hot plasma is transferred to the Corona.
• As per the researchers, the observations revealed that the hot plasma heats up these spicules making them attain Coronal temperature.
• The hot plasma consists of a mixture of negative and positive ions that are electrically charged.
• They further found that the plasma emits extreme ultraviolet light and the coronal intensity increases as the spicule propagates upwards.
• 1.6-metre Goode Solar Telescope at the Big Bear Solar Observatory (BBSO), the world’s largest solar telescope, was used for making the observations.
• The researchers matched these observations with the Atmospheric Imaging Assembly in NASA’s Solar Dynamic Observatory spacecraft.

Key Findings

• The burst of spicules originates from a web-like network of magnetic structures on the surface of the Sun.
• At the footprints of the spicules, magnetic elements with opposite polarity to the magnetic network emerges.
• Researchers also observed that opposing polarity cancels out on meeting each other, at the exact same time spicules that heat up the upper atmosphere appeared.