If you post this in the forum - the Picture Feedback Forum would be best - folk may answer you.

This section is not for queries but for folk to post tutorials.

As long as it's here I throw in my two penny worth. It's probably what is known as  Digital Noise in digital photos and was grain in film pics. Rather than trying to explain it, here is an excerpt from an explanation I have copied from;-

http://www.cambridgeincolour.com/tutorials/image-noise.htm

"Image noise" is the digital equivalent of film grain for analogue cameras. Alternatively, one can think of it as analogous to the subtle background hiss you may hear from your audio system at full volume. For digital images, this noise appears as random speckles on an otherwise smooth surface and can significantly degrade image quality. Although noise often detracts from an image, it is sometimes desirable since it can add an old-fashioned, grainy look which is reminiscent of early film. Some noise can also increase the apparent sharpness of an image. Noise increases with the sensitivity setting in the camera, length of the exposure, temperature, and even varies amongst different camera models.

PS Did you try the pro low light mode. In this instance it may just have been too dark for that, also I would add, that if you had used a larger apature  you could have possibly got the shutter speed dowwn to 5 sec which would also help to reduce noise

Hope this helps