Why are my images so noisy?

[Fotografer]

Hey guys. So, I've just noticed that my images are more or less, grainy. I have no idea why, even in bright conditions, with ISO 100, I get loads of grain. It just doesn't come out smooth.</p>
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<p>My camera specs:</p>
<p>12.1 Megapixels</p>
<p>4/3rds sensor.</p>
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<p>Thanks!</p>
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<p>P.S. sometimes i take shots of the sun, mostly at sunset, but occasionally I point my camera directly at the Noon sun. Would it have damaged my sensor? but those are like f/22 with 1/4000 shutter speed, shouldn't be too bad, should it?</p>
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<p>Taken with 2 second shutter, f/5.6, ISO 100</p>
<p>Original Image:</p>
<p><img src="http://img209.imageshack.us/img209/6614/screenshot20101114at952.png" border="0" alt="" /></p>
<p>a section of the fullsize image, you can see the graininess:</p>
<p><img src="http://img264.imageshack.us/img264/6614/screenshot20101114at952.png" border="0" alt="" /></p>
<p>&n