Close up on THE SUN

Together, Solar Orbiter and the Parker Solar Probe are giving us our closest ever look at the Sun. With both now in their science phases, Ezzy Pearson updates us on what we've already learned and what's still to come

- Ezzy Pearson

Although the star at the heart of our Solar System outshines everything else, its very brightness defies attempts to better understand it. Its light blinds any who look at it, while its heat scorches craft that venture too close. Despite this, specialised observatories have allowed solar astronomers to look on from afar over the years.

But now there are two telescopes giving an up-close view of the Sun. On 26 March, the European Space Agency's Solar Orbiter probe sailed past the Sun on its closest approach yet, coming within a third of the Earth-Sun distance to our star. And last year, its observing cousin, NASA's Parker Solar Probe, passed so near to the Sun that it flew through the outer layers of its atmosphere, sniffing out the pristine particles near the solar surface. But despite the pair being closer to the Sun than any other mission, they are looking at the star in two very different ways.

Big plasma bubble

"Solar Orbiter is a mission to explore the Sun and the surrounding heliosphere - the big plasma bubble that the solar wind blows into the interstellar medium," says Daniel Müller, project scientist for Solar Orbiter at the European Space Agency. "The driving rationale for Solar Orbiter is to establish the connections between what our home star does in terms of activity and how that manifests itself in the surrounding heliosphere, including the near-Earth environment. We combine measurements of the plasma at the location of the spacecraft with images of the Sun."

The mission launched on 10 February 2020, and has spent the last two years looping around our star. It spends much of its orbit at a distance to protect itself from the searing heat, only swooping in every five to six months for a close pass known as perihelion. Using flybys of Earth and Venus to pull its orbit close to the Sun, it now passes just 48.3 million km from our star.