Hoping for some kind of warning sign before the sun spews forth a fiery ball of death aimed right at our favorite planet Earth? Science has just discovered that we may be out of luck.

NewScientist reports that scientists have discovered that, last year, the sun released a plasma bubble called a coronal mass ejection (or CME, for short) while still seeming otherwise tranquil:

The sun ordinarily gives some warning when it is about to let loose a CME. Plasma filaments, flares, dim areas, and bright S-shaped sigmoids are often associated with the events.

However, in the past decade or so, solar physicists have measured a number of mild magnetic storms around Earth that seemed to be associated with "stealth" CME's – eruptions that occur with no clear sign of where they might have originated on the sun.

The CME in question was a burst of 3 billion tonnes of solar material, a not-uncommon size that - if it were aimed at Earth - could affect migration patterns of birds and affect power grids, but NASA solar physicist Ron Moore isn't too concerned:

All the big dangerous things come from much more powerful explosions, which as far as we know are always strong enough to make some signature on the face of the sun.

Well, that's reassuring. At least we'll probably be able to see what caused us all that trouble. As far as we know.

Stealth storm erupts from the sun [New Scientist]