The sun’s otherworldly landscape, including coronal fog, solar rain and 6,000-mile-tall gas towers, is revealed in footage from the Solar Orbiter spacecraft.
The observations, beamed back by the European Space Agency probe, reveals feathery, hair-like structures made of plasma and also captures bursts and showers of relatively cooler material falling to the surface.
Scientists say the observations of the sun’s complex surface dynamics could help solve the question of why the sun’s atmosphere is so much hotter than its surface – a long-standing paradox in solar physics.
The brightest regions are around 1,000,000 C, while cooler material, falling below 10,000 C, appears darker. The imagery was captured by the Extreme-Ultraviolet Imager (EUI) instrument on September 27, 2023, when the spacecraft was about a third of Earth’s distance from the sun.
The annotated video highlights delicate lace-like patterns across the sun, called coronal moss. These structures appear around the base of large coronal magnetic field loops. On the horizon, gas towers known as spicules rise from the Sun’s chromosphere to heights of about 6,000 miles (10,000 km).
In the center of the field of view, a small eruption is visible, with cooler material being lifted upwards before mostly falling back. Although small relative to the largest events, this eruption is still larger than Earth.
The imagery also reveals coronal rain, which at less than 10,000 C appears dark against the bright background of large coronal loops (about 1,000,000 C). The rain is made of higher-density clumps of plasma falling back towards the sun under the influence of gravity.
“It’s really beautiful when you see it happen,” said Dr David Long, a solar physicist at Dublin City University and Solar Orbiter scientist. “It kind of comes and goes — you see showers of it around solar flares.”
The observations may help explain why the sun’s outer atmosphere (known as the corona) is more than 150 times hotter than its surface at more than 1,000,000 C.
The corona is expected to be cooler because the sun’s energy comes from the nuclear furnace in its core, and things naturally get cooler the further away it is from a heat source. One explanation is that miniature flares, called campfires, pump energy into the atmosphere to cause coronal heating.
“It’s still a bit of an open question,” Long said. “These campfires that Orbiter observed for the first time just keep going off.
“It works out how much energy they produce and whether it is enough to heat the atmosphere to what we see. It’s the combination of all these different characteristics.”
The $1.3bn (£1bn) mission was launched in 2020 and next year will begin to climb out of the planetary plane to provide the first glimpses of the sun’s uncharted north and south poles.
