NASA solar scientist Holly Gilbert explains a computer model of the sun’s magnetic field. Grasping what drives that magnetic system is crucial for understanding the nature of space throughout the solar system: The sun's invisible magnetic field is responsible for everything from the solar explosions that cause space weather on Earth to the interplanetary magnetic field and radiation through which our spacecraft journeying around the solar system must travel.
HOLLY GILBERT, NASA SOLAR SCIENTIST: The sun is a beautifully magnetically driven star, but we can't actually see magnetic field lines. They are essentially invisible, and so we have to turn to models in order for us to see the global magnetic structure of the sun.
What we're looking at here is one such model. And the colour colour coding represents what we call open magnetic field lines, which means that they extend from within the sun all the way out to really, really far out in space. The green and the purple have a north and a south polarity. The white lines are closed magnetic field lines, so they come out from the surface of the sun, and then they loop around and close near the solar surface.
You can see how beautifully dynamic the sun is, as well. Magnetic field lines interact with each other, they cause big explosions to occur on the sun, and that's one reason it's extremely important to study the magnetic structure of the sun, especially on a global scale. And again, models are one way we can do this, because they allow us to model where the field lines are, how they're going to interact with each other when the sun rotates, and then how that causes solar storms like coronal mass ejections and solar flares.
Sometimes the sun is quiet, sometimes the magnetic field lines aren't doing a whole lot, but other times you see these bright regions on the sun, where you have closed loops. And that's where activity can occur, where the flares can occur.