Top Ten Astronomy Pictures of 2009

By Phil Plait | December 15, 2009 6:00 am




#9: A Computer’s Spot in the Sun

Dark blemishes on the Sun have been known since antiquity; when the setting Sun’s disk is dimmed by dust in the air, you can sometimes see sunspots against its reddened face. Those are monster spots, and very rare, but even the normal run-of-the-mill sunspots aren’t well understood.

But that’s changing. In the 1850s came the first hints that sunspots were magnetic in nature, and over the past 15 decades we’ve made quite a bit of progress. We now know that sunspots are manifestations of the Sun’s seething and complex magnetic field. Where the field lines erupt from the surface, the hot solar gas is constrained like a prisoner in a cell. The gas cools, but cannot sink back down beneath the surface. It stays put, looking dark against the Sun’s otherwise blinding light.

Magnetic fields are incredibly difficult to model mathematically, but as computers improve, so does our ability to understand magnetic behavior. That picture above looks just like a sunspot, but it isn’t: it’s a computer-generated simulation of the flow of gas on the Sun as it is squeezed by the solar magnetic fields. It’s the first time a sunspot has been modeled in three-dimensions, and is a breakthrough for scientists studying how the Sun works. It’s also a first for my Top Ten posts: a picture that’s not of a real object! But how could I leave it off? It’s so awesome!

And this affects you too. In 1989 a giant magnetically-driven ejection of material from the Sun caused a massive power outage in Quebec in winter, and did billions of dollars of damage. Understanding how the Sun works in this way can help us predict when these events are likely to happen. That’ll save money and lives. And we’re expecting the Sun to start ramping up on sunspots again in just a few years…

Original news story

BA Blog post

Credit: Matthias Rempel, NCAR



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