Early this morning, while you were sleeping, or working, or reading Twitter, the Sun had different plans: it erupted, blasting an immense tower of plasma upward off its surface:
[Click to enheliosenate.]
This image was taken by NASA's Solar Dynamic Observatory at 08:15 UTC this morning. The scale of it is staggering. The Sun is 1.4 million kilometers across - 860,000 miles - so this plume was at least 400,000 km long. Going back through the images, it had been brewing for hours, but really got its start around 05:00, meaning it erupted upwards at well over 100,000 km per hour. That's fast enough to cross the face of our planet in less than 8 minutes.
By the way, did I mention the total mass of such a prominence is billions of tons? And the Sun does this kind of thing all the time.
We're in no real danger from an eruption like this, especially this one: it's on the Sun's limb, so it was heading away from us. But these events can trigger storms like coronal mass ejections, where billions of tons of material is sent hurtling across the solar system at mind-crushing speeds. Those can interact with our magnetic field, creating havoc with our satellites and causing power outages.
But that's why we keep an eye - many eyes, in fact - on our Sun. Never forget: our Sun is a star, with all the power and fury that implies. The better we understand it, the better we can protect ourselves from it when it gets angry.
Image credit: NASA/SDO. Tip o' the welder's glasses to Camilla SDO.