The uppermost layers of the Sun’s atmosphere are thousands of times hotter than its surface, and a new study suggests that this mysterious temperature difference can be explained by weak but persistent waves propagating through the region.

The “surface” of the Sun (the photosphere, or the visible part of the Sun) has a temperature of about 10,000 degrees Fahrenheit (5,500 degrees Celsius). Oddly enough, despite being farther from the Sun’s core, the uppermost part of the Sun’s atmosphere (known as the corona) is much hotter, regularly reaching temperatures around 1.8 million to 3.6 million degrees F (1 million to 2 million degrees F). reaches million degrees C). . The temperature of the corona sometimes even reaches 72 million degrees F (40 million degrees C), according to NASA.

The corona, which consists of hot ionized gas called plasma, is also where extreme space weather events such as solar flares occur. However, it is still unclear how the corona got so hot.

In the new study, researchers investigated widespread solar-related oscillations known as low-amplitude undamped oscillations. These are oscillations in coronal loops, or arc-like plasma structures, that start in the photosphere and propagate to the lower corona. These waves are relatively weak, but their strength does not weaken over several cycles of oscillation. Therefore, it has the potential to provide large amounts of energy to the corona over time.

Scientists focused on how these waves oscillated up and down, left and right, or any angle in between; This property is known as polarization. Being able to analyze this aspect of the waves’ three-dimensional geometry can shed light on the origin of the waves and how much energy they have. But scientists have not previously found a way to examine these waves under multiple viewing angles and thus detect the polarization of the event.

In the new study, researchers used data from the European Space Agency Solar Orbiter and NASA’s Solar Dynamics Observatory will analyze the solar corona from multiple vantage points. They successfully detected a 4-minute undamped end-to-end oscillation of the coronal ring.

Scientists discovered that almost all of these waves vibrate in the same direction. This suggests that these are “probably related to long-term flows on the Sun’s surface,” study co-author Valery Nakaryakov, a solar physicist at the University of Warwick in Coventry, England, told Space.com. This discovery shows that energy from the Sun’s surface can reach the corona and heat it. “Our discovery provides important information to answer the age-old question of what heats the Sun’s corona,” Nakaryakov said. said. Source