What is the sun made of and why is it so hot? Nasa mission helps unravel the mysteries

The whole world literally revolves around it, yet it still remains one of the most puzzling bodies in our galaxy.

 

When it comes to the sun, many questions remain unanswered, such as how it manages to generate such intense heat, what causes solar wind, and how solar flares are caused. 

 

But a mission launched by Nasa has brought scientists a step closer to gaining a clearer understanding of how our nearest star transfers energy through its atmosphere, and has helped them track the dynamic solar activity that can impact technological infrastructure in space and on Earth.

 

Using its Interface Region Imaging Spectograph (Iris), the US government space agency studied the sun's surface in detail, paying particular attention to its extremely hot atmosphere. 

 

"The results focus on a lot of things that have been puzzling for a long time and they also offer some complete surprises," said De Pontieu, one of the lead researchers in the study. The discoveries are published in the journal Science.

 

The scientists gained insight into the heating mechanisms throughout the solar atmosphere by identifying heat pockets at a temperature of 200,000 degrees Fahrenheit. These pockets were lower in the solar atmosphere than observed by any spacecraft before, and have been described as “solar heat bombs” because of the intense energy they release in a short period of time. 

 

A particular surprise to researchers was the discovery of structures resembling mini-tornadoes in solar active regions of the sun. These move at speeds as fast as 12 miles per second, and are scattered throughout the chromosphere – the layer of the sun in the interface region just above the surface. 

 

These tornados were found to transfer energy to power the sun's atmosphere, shedding light on how this region reaches often million-degree temperatures.

 

The mission also uncovered evidence of high-speed jets at the root of the solar wind. The jets are fountains of plasma that shoot out of coronal holes, areas of less dense material in the solar atmosphere and are typically thought to be a source of the solar wind.

 

"These findings reveal a region of the sun more complicated than previously thought," said Jeff Newmark, interim director for the heliophysics division at Nasa headquarters in Washington.

 

"Combining Iris data with observations from other heliophysics missions is enabling breakthroughs in our understanding of the sun and its interactions with the solar system."