In the world of photography, lighting is extremely important! It really makes or breaks a picture. It's what makes the difference between an everyday snapshot and an awesome photo, and after today you'll know how to deal with it like a pro!
Front lighting would be as if you were looking at the sphere from the same direction as the light was coming. You would only see the highlighted areas, and the shadows are now lost from your view. This produces a flatter, two dimensional look. But this can be flattering because it tends to minimize the appearance of any imperfections such as blemishes or wrinkles (since they do not cast a shadow as they would with side lighting).
My favorite is back lighting! This would be as if you were looking at the sphere directly opposite from where the light was coming, so you would just see the shaded side of your subject. I love the soft hazy look that the light creates as it comes directly at the lens!
Remember that you are now on the shaded side of your subject, and in order for your subject to be properly exposed (not too dark), you'll need to over-expose the scene in general. You can see that the background is very bright and over-exposed, but the subject is perfectly exposed (with no harsh contrast) and that's what's important.
So go out and start experimenting with lighting! It's a really fun subject and it's so exciting when it all begins to make sense and your pictures begin to look amazing!