NASA, NOAA, and the International Solar Cycle Prediction Panel have confirmed the Sun has reached solar maximum, slightly earlier than expected in its 11-year cycle. Thanks to the solar probes, telescopes, and missions currently studying our star, this is not the solar maximum of 2014, we can now study it in detail in ways never seen before. 

The solar maximum is the moment the Sun reaches peak activity in the solar cycle, with an impressive number of sunspots on its surface and releasing more radiation, solar flares, coronal mass ejections, and other explosive events that are all happening with increased power and frequency right now.

This is the current maximum of Solar Cycle 25 – the 25th since 1755, when the extensive recording of solar sunspot activity began – which started in December 2019. It is expected to last until 2030. We will only know when the cycle actually peaked after it has passed but this is going to be the best-studied maximum of any other on record. We have space- and Earth-based telescopes and spacecraft that are looking at the Sun in unprecedented ways, and they are already delivering revolutionary insights into our star and what happens during its most violent period.

The big players studying the Sun

There are three big players in this cutting-edge work. On Earth, the National Science Foundation’s Daniel K. Inouye Solar Telescope in Hawaii is the world’s largest solar telescope and has already taken the highest-resolution images of the Sun. In space, NASA’s Parker Solar Probe – the fastest human-made object in space – is documenting and capturing incredible images and footage as it orbits the Sun, while the European Space Agency’s Solar Orbitor – the most complex scientific laboratory ever sent to our star – is capturing detailed views never seen before. 

It was only when Parker Solar Probe became a reality that we got very close and personal with the Sun.

Dr Nour Rawafi

The two spacecraft have complementary but independent goals. Parker’s goal is to “touch the Sun”. The craft is the closest object we have ever sent near the Sun and it flies through its atmosphere collecting measurements as it goes. From December this year, it will get even closer, passing just 6.9 million kilometers (4.2 million miles) from the Sun’s surface. 

“Until recently we have been observing the Sun from afar – we couldn’t get as close – and there are some key measurements that we need in particular of this explosive activity of the Sun, like flares and coronal mass ejections. We want to make these measurements as close as possible to the Sun,” Dr Nour Rawafi, project scientist for Parker Solar Probe, told IFLScience. “This has not been possible since the dawn of the space age. It was only when Parker Solar Probe became a reality that we got very close and personal with the Sun.”

Parker has no cameras looking directly at the Sun. A camera looking at the Sun at those distances would cause the spacecraft to cook from the inside out. But for pictures, that’s where Solar Orbiter shines. The ESA spacecraft at its closest is still several times farther away from the Sun than Parker but it can deliver incredible images thanks to its suite of cameras.

“The key uniqueness of Solar Orbiter is two things: First, we get in very close to the Sun, and so we get to study the relationship between the Sun itself and the so-called pristine solar wind. The second thing is that, starting from next year, we actually get to look at the magnetic field of the poles of the Sun,” Dr David Williams, Instrument Operations Scientist for Solar Orbiter, told IFLScience.

In fact, Solar Orbiter will go where no spacecraft has gone before by moving farther and farther away from the ecliptic plane. Basically, the spacecraft’s orbit will be slanted compared to the orbit of Earth, and that will allow it to see and study the poles of the Sun for the first time.

That is certainly a unique perspective of the Sun but also of the explosive events that the Sun releases such as coronal mass ejections, which, if they are very strong and hit Earth, cause the spectacular auroras we have been seeing this year. Solar Orbiter was instrumental in measuring how the sunspot responsible for the global May auroral event behaved when it was on the far side of the Sun from Earth’s point of view. It recorded one of the most powerful flares in 20 years, which messed with even the robots on Mars.

When we’re out of the ecliptic plane, starting from 2025, we are going to get another vantage point to look at the solar storms that come out of those active regions. This is not the same as looking at those CMEs from the ecliptic plane.

Dr Miho Janvier

“That measurement was made thanks to our hard X-ray spectrometer on board the spacecraft. It gives us a view of solar max from another vantage point, depending on where we are in the orbit,” Dr Miho Janvier, solar and space physicist at the European Space Agency, told IFLScience. 

“When we’re out of the ecliptic plane, starting from 2025, we are going to get another vantage point to look at the solar storms that can come out of those active regions, something that is quite dear to my heart. This is not the same as looking at those coronal mass ejections from the ecliptic plane.”

The incredible capabilities of these spacecraft shouldn’t make us underestimate how we can observe the Sun from the ground. The US National Science Foundation Daniel K. Inouye Solar Telescope, with its 4m-diameter aperture, has already delivered incredible images of the Sun, including a sunspot larger than Earth. And just like in space, the approach on Earth is multiwavelength. From radio to hard X-rays, the Sun is being kept under close observation.  

“The Inouye Solar Telescope is the largest solar telescope by some margin, providing observations of the Sun in unprecedented high resolution. Capacities at radio and microwave wavelengths have also come a long way, from improvements across multiple facilities – including the Expanded Owens Valley Solar Array and Low-Frequency Array,” Dr Ryan French, from the National Solar Observatory who previously featured in our The Big Questions podcast episode on the next big solar flare, told IFLScience.

Revolutionary Observations For Solar Science

All the teams we spoke to stressed that these spacecraft and telescopes are not designed with the specific goal of studying the solar maximum in mind, but they are equipped with the right tools to make the most of this exciting, active period. Parker and Solar Orbiter were launched at either side of the last solar minimum, and the Inouye telescope had its first light right between them.

“When the sun is quiet was the perfect time to launch Parker Solar Probe. The reason for this is that by its nature, the environment of the Sun is so complex that it is best to start from the basic state of that environment. When solar activity builds up, more complexity will come with it, and then we will build our understanding as we go,” Dr Rawafi explained.

“Solar Orbiter is not aimed to look at solar maximum, as some specific solar activity missions are but it is bringing some unique things to the table,” Dr Williams explained.

“It does have a lot of instruments on board that have the capability to look at this maximum activity, whether it’s imaging the hard X-rays or the particles that are traveling from the Sun,” Dr Janvier agreed.

The data that has been collected since these instruments have come online has been nothing short of revolutionary. We are getting close to solving long-standing mysteries such as the coronal heating problem, especially when they work together, and solar scientists continue to pour over the data collected over the last five years. Imagine what we will learn from the solar maximum observations from all three.

“Although most solar missions will have lifespans extending beyond the solar cycle, the data obtained during this solar maximum will be pivotal in starting to answer these fundamental questions about our local star,” Dr French brilliantly summarized.

The next several months will be extremely exciting. Huge flares, coronal mass ejections, and more spectacular aurorae will be a continuous presence in the news. Lucky us to live in a time where we are studying this fascinating period of the solar cycle like never before in the history of our species.