14 December 2010


Well, not on Earth. But if you lived on the surface of the Sun (assuming you could survive the 10,000 dF / 5500 dC incandescent temperatures -- core temperatures are orders of magnitude hotter, up to 7,600,000 dF / 13,600,000 dC), your sky would definitely be falling. In Global Eruption Rocks the Sun, NASA's Science News website reports that "On August 1, 2010, an entire hemisphere of the sun erupted. Filaments of magnetism snapped and exploded, shock waves raced across the solar surface, billion-ton clouds of hot gas billowed into space. Astronomers knew they were witnessing something big. It was so big, it may have shattered old ideas about solar activity .... Explosions on the sun are not localized or isolated events. Instead, solar activity is interconnected by magnetism over breathtaking distances. Solar flares, tsunamis, coronal mass ejections -- they can all go off at once, hundreds of thousands of miles apart, in a dizzyingly-complex concert of mayhem."

Above is an image of an isolated solar flare, a million or more miles long. Below is an image using extreme ultraviolet light, showing the global solar eruption, with magnetic fields delineated by white lines.

The sheer scale of astronomical objects, and the events linking them, boggles the mind. Consider the sun -- if you lined up 109 Earths in a row, you would have roughly the diameter of the Sun. Its surface area is 11,990 times that of Earth. Its volume is 1,300,000 times that of Earth. Its mass (not the same as weight, but think weight for convenience's sake) is 333,000 times that of Earth. And, given all that mass, the Sun's escape velocity, the speed you have to be traveling upward to break free from the Sun's gravitational field, is 55 times that of Earth.

So you can see that a true global eruption, i.e. one that affects the entire surface of the globe of the Sun, is a very big deal. The amounts of matter and energy involved are beyond comprehension. And to think that our sun is only a medium-sized, medium-hot star among the ten billion others in our Milky Way galaxy alone. And our galaxy is but one of (as Carl Sagan would have famously intoned) billions and billions of galaxies in the universe.

Here's a fun way of wrapping your mind around the vast distances involved -- a brief video called Powers of Ten -- the unimaginable size of our universe.

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