|Credit: APOD, Juan Manuel Pérez Rayego|
Look very carefully at that sunset picture. Ignore the birds, the tree, and the bands due to the thin clouds in our own atmosphere. On the disk of the Sun itself, you can clearly see some spots. That's not a defective camera lens, those spots are actually on the Sun. The big one there is sunspot group 1429, which you can also see in this other APOD picture:
|Credit: APOD, Alan Friedman|
Sunspot group 1429 is a particularly large set of sunspots that was quite active a few weeks ago. You may have heard the news of a massive solar flare emanating from this region around March 7th or so. This increase in solar activity happens periodically as the Sun reaches solar maximum.
One last thing I want to point out is the scale of these sunspots. If you look at the first image you'll see a few smallish spots near the center. Each of those is larger than the planet Earth. The Sun is big, and yet it is an average star that's just one of a hundred billion or so stars in our own Galaxy.