A super-volcano in Yellowstone could ruin our whole day.
We'd have a better seat for the supernova explosion of Eta Carinae -- that would only fry the southern hemisphere with gamma rays, leaving those of us in North America relatively untouched.
Eta Carinae is one of the largest stars in our galaxy -- and one of the most unstable. It's also situated 8000 light years from us, "just down the street" in galactic terms.
It already puts out more than five million times the energy our Sun does. When it finally blows, it will for a time produce more energy than all the other stars in the galaxy combined. And we have a front row seat. Be sure to wear your 10,000,000 SPF sunscreen.
When will it go off? No way to tell, it's extremely unstable and unpredictable. But it has been growing strongly in intensity over the past ten years. If it keeps up, it'll be the second brightest star in the sky in just a few more years (right now it's quite dim in the sky due to its distance). The last time this happened (1841) it threw off a huge blast of matter that formed the "dumbbell" shaped nebula you see in the Hubbel photo above.
To give you an idea of the scale of that blast, the smallest features visible in that photo are each about the size of our entire solar system.
But there's no guarantee it'll only sputter this time. All we know is that it's definitely ramping up for another "event".