This morning, the European Space Agency and NASA have unveiled the next solar images ever taken by a spacecraft: high-resolution images taken by their newly launched Solar Orbiter spacecraft. The pictures already reveal strange phenomena on the sun that we have never seen in such detail.
“We didn’t really expect the first few pictures to be that great,” says Daniel Müller, ESA project scientist for the Solar Orbiter mission The edge. “Not only are they very sharp and perfectly exposed from a technical point of view, they also show things that we have never seen before.”
Thanks to these images, scientists have discovered that these are relatively “tiny” solar flares that are distributed over the surface of the sun. The scientists behind the mission called these small torches “campfires” because they are millions to billions of times smaller than the massive, energetic torches that regularly emanate from the sun. Dozens of these campfires can be seen at any time in the field of view of the Solar Orbiter camera. “It is fascinating that they seem to happen everywhere in the sun all the time,” says Müller.
It is unclear exactly what is causing these mini flares. Typical solar flares often occur when the sun is considered active – when dark spots of sun appear on the surface of the star and parts of the solar magnetic field rotate and turn. Such events cause tensions to build up, eventually breaking off the magnetic field near the sunspot, releasing a huge burst of high-energy particles emanating from the sun. However, these campfires do not appear to be near sunspots or places of intense sun activity. In fact, the sun has an 11-year cycle that alternates between periods of extreme solar activity and periods of rest – and things are pretty calm right now. “It’s really nothing special in an area where there are no sunspots, but it shows up everywhere,” says Müller.
The discovery of these campfires is only the first major find from Solar Orbiter, a joint mission between ESA and NASA, which was launched on February 9 from Florida. The spacecraft’s mission is to get an unprecedented view of the sun’s poles, a vantage point that we have never seen before with a spacecraft. It will take approximately two years for Solar Orbiter to enter orbit to observe the sun’s polar regions. In the meantime, the vehicle has tested its range of 10 scientific instruments – including its on-board cameras.
When Solar Orbiter took these pictures, it was only 77 million kilometers or nearly 48 million miles from the sun. That is about half the distance between the sun and the earth. No spaceship has ever taken pictures of the sun’s surface from such a short distance. This includes NASA’s other sun-colored spacecraft, the Parker Solar Probe, which was launched in August 2018 to study the scorching hot atmosphere of the sun. The Parker Solar Probe is already within 18.7 million kilometers or 11.6 million miles from the sun’s surface, making it the human-made vehicle that comes closest to our mother star. However, the Parker Solar Probe does not have a camera that directly images the sun’s surface, and this is where Solar Orbiter comes in handy.
The images collected by Solar Orbiter are approximately twice the spatial resolution of the images taken by NASA’s Solar Dynamics Observatory, which is currently in a very high orbit above Earth. This spaceship photographs the sun every day, while collecting images through Solar Orbiter is not that common.
Solar Orbiter will swing from Venus and Earth over the next year and a half to get closer to the sun. At some point it will be closest to the sun and will be within 42 million kilometers or 26.1 million miles. This means that the images only get better over time. “Since the camera itself does not have a zoom function, zooming takes place by approaching the sun,” says Müller.
Hopefully, scientists can learn more about these campfires and their drive. You are curious whether these mini-torches could explain a long-standing riddle: Why the atmosphere of the sun is so hot. Known as the corona, the atmosphere that surrounds it is incredibly hot, even hotter than the sun itself. A theory suggested by astrophysicist Eugene Parker – the namesake of NASA’s Parker Solar Probe – states that small solar flares on a small scale in the occur throughout the sun and warm the atmosphere. “A large number of small energy surges are released,” explains Müller. “Each of them almost invisible and insignificant, but overall they could add enough energy to heat the corona.”
It is far too early to say that these campfires are the source of the super hot atmosphere of the sun. Scientists also need to make more detailed observations to find out the temperature of these campfires and really make a connection. But the discovery is exciting and Müller is optimistic that the closer the solar orbiter gets to the sun and when the spaceship really starts to play its muscles, they will learn more. “What will be the key is to harness the power of the various Solar Orbiter instruments,” he says.