‘Expotition’ to the south pole (of the sun)

This week we've been treated to images of the sun's south pole for the first time! As a child learning to read, a particular favourite story of mine was Winnie-the-Pooh's 'expotition to the north pole' with Christopher Robin and his pals, so as soon as I saw this polar news story it brought back happy memories and a chuckle.

This year, the Solar Orbiter probe explores the sun’s south pole for the first time. Credit: ESA

Five years ago ESA and NASA launched the Solar Orbiter probe to observe our closest star in detail and explore its previously unseen regions. The spacecraft travels at speeds of up to 33km/s (or 118,000 km/h), has a pricetag of £1.3 billion and will observe the sun from around 26 million miles away, just over a quarter of the distance between Earth and our host star. Even at this distance, temperatures can reach a sweltering 500 Celcius, so the delicate instruments are protected from the heat by a titanium shield.

The sun plays a huge role in our everyday lives, not just providing the luminosity that allows us to see, but giving the energy and warmth that allows almost everything on Earth to live. What most people aren't aware of is that solar activity can cause disruptive 'space weather', resulting in extensive damage to satellites and communication systems on which much of modern business life depends. For this reason, one of the aims of the Solar Orbiter will be to observe the sun to improve current models of solar activity, so that we can predict and be better prepared for such events in future. Another mission aim is to analyse the sun's magnetic field, which becomes increasingly active every 11 years, producing more sunspots and solar flares. These intense energy bursts are caused by the rapid release of magnetic energy, sending charged particles zooming towards Earth, which can be fun if it causes beauitful auroras, but less so if power grids and communications are knocked out. At the peak of this solar activity cycle, the sun's magnetic field flips, with the north pole effectively becoming the south and vice versa. How this crazy process occurs exactly is not fully understood, but given the potential consequences, it is important the science behind this is better understood.

A video zooming in on the solar south pole can be accessed on the ESA website here.

There is another puzzle about the sun, which is that the upper atmosphere is several million degrees hotter than the surface. In order to understand how the sun operates in full, the whole surface needs to be observed, and the polar regions have until recently remained unseen. The surface layer we see with our eyes is called the photosphere and has a temperature of around 5600 Celcius, while the upper atmosphere (corona) reaches millions of degrees.

I would be lying if I didn't say the pretty pictures (lots of those in astrophysics!) weren't also one of the reasons to write this article, however it seems to me that when studying astrophysics, our own solar system and local star are often overlooked in favour of exotic systems further away. This seems a shame, since we would not exist without our sun, in most other aspects a fairly ordinary star, but one on which our lives all depend, so it seemed only fair to devote an article to the beating heart of our solar system!

In other news, yesterday I completed my last university exams(!!!) and am in the process of wrapping up my masters course with the last pieces of coursework due this summer, followed by more physics themed adventures afterwards! I'll also be interning in a patent attorney office for a week, so am looking forward to meeting more physicists there and learning about how scientific devices are patented. The next articles may cover topics including but not limited to: planet formation, the origins of life on Earth, the history of amateur radio astronomy, the physics of sailing boats, and anything else cool and sciencey that pops up. In the meantime dear reader, open your eyes and take a look at the incredible world around us, from the twinkling stars in the sky to the liquid crystal display in the screen you're reading this on, there really is fascinating science all around us, and you definitely don't need to be a nerd to appreciate it. :))