Why send a probe to the sun?

Chris Smith put this question to astronomer Matt Bothwell...

Matt - This is the Parker Solar Probe, which is going to be launched this summer - August 2018 it’s planned to go up. It’s basically going to let us answer loads of questions about our Sun that we don’t understand at the moment. It sounds a bit weird, right, that we might not not understand things about our Sun. We’ve been observing it for hundreds and hundreds of years, but there are quite a lot of mysteries about the Sun and there are things that we’d like to clear up.

One of the really big ones is what we call the Coronal Heating Effect. It’s one of the big unsolved mysteries in physics. The corona around the Sun - if you can think of it like the Sun’s atmosphere - it’s all this superheated plasma around the Sun. The weirdest thing is it’s much much hotter than the solar surface. The surface of the Sun is maybe a few thousand degrees, and the corona is millions of degrees, which seems to violate thermodynamics. You can’t have something cooler heating something hotter! So there has to be something quite weird going on, maybe involving magnetic fields that we don’t understand.

What the probe is: it’s going to be the first thing that’s actually going to visit the star. It’s actually going to go into the corona and take measurements, and let us solve these kinds of problems. It’s not, of course, just the coronal heating problem. It’s going to help us better understand the solar winds which is going to let us learn how to protect our satellites better and also is going to have implications for understanding how we can make spacecraft to launch humans into the distant solar system.

Chris - What’s the timescale over which this is all going to be happening?

Matt - It’s launching August this year. I think it will take a few years to get to the Sun. It’s going to do various flybys around the solar system to build up exactly the correct speeds to descend into the Sun, but it’s going to be a few years before it actually gets there...