YosemiteSam
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If you find space cool, but don't read Philip Plait's Bad Astronomy blog. You're really missing out.
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The Wonderful
The image above is substantially cool. But it’ll take a moment to explain why. Stick with this; you’ll like it.
In the constellation of Cetus, the whale, is what appears to be a run of the mill red star. At a distance of about 400 light years, the fact that you can see it with your unaided eye at all means it’s an intrinsically luminous star: at that distance the Sun would be completely invisible.
The star is a red giant, a star that was once much like the Sun but is now terminally ill. Stars make energy in their core through the fusion of light elements into heavier ones; the Sun is currently fusing hydrogen into helium. Eventually it will run out of hydrogen, and will begin to fuse helium into carbon and oxygen. In 7 billion years or so the helium in the core will run out as well. The carbon and oxygen ash from the process will form a ball about the size of the Earth. It will contract and get incredibly hot. Helium outside the core, previously unavailable for fusion (like having a spare can of gasoline in the trunk of your car) will start to fuse in a thin shell surrounding the core. This will dump vast amounts of heat into the outer part of the Sun, which will respond like any gas will when heated: it will expand and cool.
Complete Blog Post
===============================
The Wonderful
The image above is substantially cool. But it’ll take a moment to explain why. Stick with this; you’ll like it.
In the constellation of Cetus, the whale, is what appears to be a run of the mill red star. At a distance of about 400 light years, the fact that you can see it with your unaided eye at all means it’s an intrinsically luminous star: at that distance the Sun would be completely invisible.
The star is a red giant, a star that was once much like the Sun but is now terminally ill. Stars make energy in their core through the fusion of light elements into heavier ones; the Sun is currently fusing hydrogen into helium. Eventually it will run out of hydrogen, and will begin to fuse helium into carbon and oxygen. In 7 billion years or so the helium in the core will run out as well. The carbon and oxygen ash from the process will form a ball about the size of the Earth. It will contract and get incredibly hot. Helium outside the core, previously unavailable for fusion (like having a spare can of gasoline in the trunk of your car) will start to fuse in a thin shell surrounding the core. This will dump vast amounts of heat into the outer part of the Sun, which will respond like any gas will when heated: it will expand and cool.
Complete Blog Post
